Citation: Christian M. Julien, Alain Mauger. Functional behavior of AlF3 coatings for high-performance cathode materials for lithium-ion batteries[J]. AIMS Materials Science, 2019, 6(3): 406-440. doi: 10.3934/matersci.2019.3.406
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Current membrane technologies are important in many industrial separation processes, especially in water purification and desalination. However, the large operating pressure gradient that is required for conventional reverse osmosis filtration makes water purification a very expensive process [1,2,3,4]. The discovery of aquaporin proteins has provided us with a revolutionary alternative to current membranes used in water purification.
Aquaporins (Aqp) are transmembrane proteins that are present in the biological membranes of organisms such as plants, mammals and bacteria [5,6]. They form pores that act as water channels, which play key roles in selectively allowing only water molecules to move across the plasma membrane while rejecting protons, charged particles and other solutes [7,8]. Aquaporin Z (AqpZ) is of special interest in water purification and seawater desalination. This is because AqpZhas been successfully expressed in Escherichia coli as reported by Soupene et al. [9], and has been purified in high concentrations to be used for integration into biomimetic membranes for water filtration [10,11]. Furthermore, AqpZ is the smallest, simplest and most robust aquaporin in the Aqp family and it can retain its properties after reconstitution in polymeric bilayer membrane vesicles [12].
Similar to other aquaporins, AqpZ naturally exists as a tetramer made up of 4 equal sub-units (or monomers) [13], with each aquaporin monomer having six transmembrane α-helical structuresand five connecting loops named A to E [12]. Each aquaporin monomer contains an individual pore, or water channel, that allows the transport of water bi-directionally withwater transport rates of up to 109 molecules per second. Loops B and E contain the most highly conserved residues, including the asparagine-proline-alanine (NPA) signature motif of Aqp, which are directly involved in the water channel function of Aqp. Loops B and E fold into the membrane from opposite sides of the bilayer, overlapping midway through the bilayer where they are surrounded by six transmembrane helices, forming the “hour-glass” model of the water channel. Owing to its unique hour-glass configuration with the NPA motif, AqpZ iscapable of achieving high water selectivity and 100% salt rejection. Three features of the water channel contribute to this high selectivity for water, which are size restriction, electrostatic repulsion and water dipole re-orientation [13]. Firstly, the narrowest constriction of the pore has a diameter of 2.8 Å [13], which is approximately the diameter of a water molecule. Hence, water molecules are physically sieved through and allowed to penetrate while other ions and solutes are rejected due to this selective property. Another feature contributing to the high water selectivity of aquaporin is the electrostatic repulsion induced by one of the conserved residue, Arg-195, located at the narrowest pore constriction [13,14,15,16]. This residue carries a strong positive charge which repels cations including protonated water, H3O+, hence preventing the passage of positively-charged ions. The third feature is that the hemipore loops carrying the NPA motifs—Loops B and E—form helices that meet midway of the channel, producing positively charged dipoles that reorient water molecules. This water dipole reorientation results in the opposite alignment of water molecules, which disrupts hydrogen bonding between neighbouring water molecules. Hence, the conductance of H+ ions is eliminated [17].
In most Aqp, the hydrophobic channels function as open channels, but some plant aquaporins, such as the spinach Aqp, have been described by Chaumont et al. (2005) to exhibit a form of gating mechanism. These Aqp are able to close up their channels under extreme conditions in order to stop water exchange altogether, which lends credence to the basis that AqpZ permeability is likely to vary with external conditions, eventhough they may or may not exhibit the same form of gating mechanisms observed [18]. However, the water filtration mechanisms by which these Aqp function are not fully understood. The protein will be influenced by external factors such as pH and temperature, which can cause a disruption to its structure and affect the protein’s functionality and properties [19]. The different external conditions can induce structural changes of the Aqp proteins and may lead to an adverse or favorable effect on the water transport and selection mechanism. Hence, it may result in a change to the osmotic permeability of AqpZ.
In addition, the thickness of the phospholipid bilayer may regulate transmembrane proteins funcationalities due to the hydrophobic mismatch between the hydrophobic length of the transmembrane proteins and the hydrophobic thickness of the bilayers [20,21,22,23,24,25,26]. To counteract the hydrophobic mismatch, either the surrounding bilayer thickness or the protein conformation will change, for example resulting in an activity change of melibiose tranporters or mechanosensitive ion channels [20,21,22,23,24,25,26]. To date, it remains unclear how the osmotic permeability of AqpZ will be affected by the hydrophobic thickness of the surrounding bialyer membrane.
Compared to phospholipids, amphiphilic block copolymers are more suitable in the fabrication of AqpZ reconstituted biomimetic membranes for the purpose of water filtration because block copolymers possess higher chemical and mechanical stability due to their chemical structures and flexible functional designs. ABA block copolymer, such as poly(2-methyloxazoline)-b-poly(dimethylsiloxane)-b-poly(2-methyloxazoline) (PMOXA-PDMS-PMOXA), has been widely used in fabrication of AqpZ-based biomimetic membrane for water purification [1,27,28,29,30,31]. It has been reported that the permeability of an AqpZ-reconstitutedPMOXA-PDMS-PMOXA membrane is 167 mm/s/bar, which is by two orders of magnitude greater than commercial polymeric membranes [1]. Therefore, we chose the amphiphilic block copolymer of PMOXA-PDMS-PMOXAs as the bilayer matrix for AqpZ reconstitution in this work.
The rationale of the present study is to gain further insight into the regulation of AqpZ permeability through environmental conditions, including the protein-bilayer hydrophobic mismatch, pH and temperature. We reconstituted AqpZ into vesicles that are made from a series of amphiphilic block copolymers of PMOXA-PDMS-PMOXA with various hydrophobic molecular weights. The osmotic permeability of AqpZ in these vesicles is determined by stopped-flow spectroscopy. In addition, the temperature and pH of the vesicle solutions were adjusted within wide ranges to investigate the regulation of osmotic permeability of the AqpZ at different external conditions.
Aquaporin Z has been prepared as reported by Calamita et al. [6] and in our previous studies [27,28,29,30,31]. Briefly, E. coli genomic DNA was extracted and the aqpZ gene was amplified and cloned into the pCR-4 vector using the TOPO cloning kit (Invitrogen, USA). The positive clones were sequenced and further subcloned into a modified expression vector, the pQE-30 Xa expression vector, with ampicillin selection and an amino-terminal 10x His-affinity tag (Qiagen, USA). The E. coli strain TOP10F was transformed and grown to 0.6-1OD at 600 nm in LB with 100 mg/l of ampicillin and subsequently induced with 1 mM of isopropyl-D-thiogalactoside. The harvested cells were resuspended in one 1/50 culture volume of ice-cold lysis buffer containing 100 mM of K2HPO4, 1 mM of MgSO4, 1 mM of phenylmethylsulfonylfluoride (PMSF), and 0.1 mg/ml of deoxyribonuclease I (pH 7.0). Cells were subjected to 4 lysis cycles in a French press (115 × 106 Pa at 4 °C). The unbroken cells and debris were separated from the cell lysate by centrifugation at 10, 000 g and discarded. Membrane fractions were recovered from the supernatant by centrifugation at 100, 000 g. AqpZ was solubilized from pellets by agitation in 1% dodecyl maltoside and PBS [12]. The solubilized protein was purified through Ni-NTA resin (Qiagen, USA), washed, and eluted with PBS (pH 7.4) and 250 mM of imidazole. The imidazole was removed using a Bio-Rad (Hercules, California, United States) Econo-Pac DG10 desalting column [32]. The resulting recombinant Aquaporin Z protein contained the 10 His-tag at the protein’s N-terminus and was utilized for embedding into membranes and vesicles.
A series of ABA triblock copolymers, poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyloxazoline) (PMOXA-PDMS-PMOXA, Polymer Source Inc.), with various hydrophobic/hydrophilic compositionsare used for AqpZ reconstitution, as shown in Table 1.
Name | ABA triblock copolymers | Hydrophobic molecular weight of the polymer (Da.) | fhydrophilic (Hydrophilic mass ratio) |
P2500 [a] | PMOXA500-PDMS2500-PMOXA500 [c] | 2500 | 28.57 % |
P4000 [b] | PMOXA1000-PDMS4000-PMOXA1000 [c] | 4000 | 33.33 % |
P5000 [b] | PMOXA1300-PDMS5000-PMOXA1300 [c] | 5000 | 34.21 % |
P8500 [a] | PMOXA1300-PDMS8500-PMOXA1300 [c] | 8500 | 23.40 % |
P8800 [a] | PMOXA2000-PDMS8800-PMOXA2000 [c] | 8800 | 31.25% |
[a] tri-block copolymers P2500, P8500 and P8800 are with hydroxyl end groups; [b] tri-block copolymers P4000 and P5000 are with methacrylate end groups which allow for a UV light induced polymerization; [c] In “PMOXAxxx-PDMSxxxx-PMOXAxxx”, the number after each block represents the molecular weight (Da.) of each block. |
The blankcopolymer vesicles were prepared using the film rehydration method shown in Figure 1. Each kind of polymer (3 mg) was dissolved in chloroform (5 ml)in a round bottomed flask. Chloroform was then evaporated slowly in a rotary vacuum evaporator at -10°C and at a vacuum of 400 mbar, to form an even andthin film of polymer at the bottom of the flask. Theresidual chloroform was further removed using a vacuum pump. The film was then rehydrated by the respective pH buffer(prepared from sodium chloride with hydrogen chloride or sodium hydroxide, with total ion concentration of 0.2 mol/L) solutions or deionized water, forming suspension with polymer concentration of 1 mg/ml. The mixture was left at room temperature with stirring for 10 h. The resultant polymersome suspension was extruded 21 times with a polycarbonate membrane with pore diameter of 200 nm to achieve unilamellar vesicles with a narrow size distribution.
The preparation procedure for proteopolymersomes was similar as above. The only difference was in the reconstitution experiments, where an appropriate amount of AqpZ solution (1 mg/ml in 2% DDM (dodecyl maltoside) wasadded to the samples duringrehydration. The detergent was removed by adding bio-beads into the mixture. The bio-beads were added every 4 h for 5 times, to allow for the adsorption process to reach equilibrium each time before the next batch of bio-beads adding into the suspension. Bio-beads were added in 5-fold excess in the last batch to ensure that the remaining detergent molecules will be adsorbed and removed entirely.The proteopolymersomes were then extruded with the same method as in the preparation of the blank polymersomes.
The extruded P4000 and P11500 polymersome suspensions were purged with argon for 10 min and further crosslinked under UV irradiation (254 nm, 6 mW cm-2) for 15 min using a BLX-E254 crosslinker (Vilber Lourtmat, France). The polymer vesicles before and after UV irradiation were freeze-dried and characterized using a Fourier transform infrared spectrometer (FTIR-8400 Shimadzu Corp., Japan) to determine the crosslinking reaction between the methacrylate groups.
Vesicle size was measured by a dynamic light scattering unit (Zetasizer 3000 HAS equipped with a He-Ne laser beam at 658 nm, Malvern Instruments Ltd., Malvern, UK; scattering angle: 90°). Vesicle suspensions were diluted to 0.01 mg/ml with DI water or respective buffer solution for the dynamic light scattering tests. An average value was obtained from three measurements.
Vesicle morphologies were measured using field emission transmission electron microscopy (FETEM), whereby the vesicles were stained on plasma-treated copper grids using 1% trifluoroacetic acid.
The permeability coefficients of various polymer vesicles with or without AqpZ reconstitution were characterized using the stopped-flow (Chirascan Circular Dichroism Spectrometer, Applied Photophysics, UK) method. For each individual stopped-flow test, 0.13 ml extruded polymersome or proteopolymersome solution with polymer concentration of 1 mg/ml was quickly mixed with 0.13 ml sucrose buffer (0.6 osmol/L), which caused water efflux from vesicles that resulted in vesicle shrinkage. At least 6 tests were performed for each sample. The dead time for the mixing of stopped flow injection was 4 ms. The vesicle size changes were monitored and recorded in the form of an increasing signal in the light scattering analysis. The initialrise of the signal curve was fitted to equation (1).
|
(1) |
Where Y is the signal intensity, A is the negative constant, k is the initial rate constant (s-1), and t is the recording time. The osmotic water permeability was calculated using Equation (2).
|
(2) |
Where Pf is the osmotic water permeability (m/s), S is the vesicle surface area (m2), V0 is the initial vesicle volume (m3), Vw is the partial molar volume of water (0.018 L/mol), and Δosm is the osmolarity difference that drives the shrinkage of the vesicles (osmol/L).
Single AqpZ channel permeability was calculated using Equation (3) [33].
|
(3) |
Pf, proteopolymersome is the permeability of the AqpZ-vesicles, Pf, polymersome is the permeability of the polymersomes without AqpZ reconstitution, and Mon/A is the number of AqpZ monomers per unit area in the proteopolymersomes.
To measure the Arrhenius activation energy of water molecules across polymer vesicles, Stopped-flow experiments were carried out at different temperatures (5, 10, 15, 20, 25 and 30 °C) for both blank polymer vesicles and AqpZ-reconstituted polymer vesicles. The exponential increase rates (k) calculated from the light scattering signals were plotted against the inverse of temperature for calculation of the Arrhenius activation energies. The comparative experiments were all tested at room temperature.
All the data presented in this study represent the mean ± standard deviation values of three experiments, unless stated otherwise. Statistical differences between groups were found using a Student’s t-test.
In this study, detailed investigation was carried out on the mechanism of water transport through AqpZ reconstituted polymer bilayers. Our aim was to establish a relationship between membrane matrix properties and the AqpZ functionality, as well as the relationship between the AqpZ permeability and the environmental conditions. Triblock copolymer PMOXA-PDMS-PMOXA is the most commonly used membrane matrix for AqpZ incorporation. The molecular structure including molecular weight, hydrophilic-lipophilic balance, functional end group and crosslinking capability, has to be considered carefully to ensure the successful incorporation of aquaporins into the vesicles to maintain its structure and function. We incorporated AqpZ into a series of PMOXA-PDMS-PMOXA block copolymers, adjusted the pH value of vesicle solutions, and controlled the temperature during stopped flow measurement, in order to investigate the influence of molecular structure of the membrane matrixand the external conditions onthe osmotic permeability of the reconstituted AqpZ.
Amphiphilic block copolymers have similar behaviour as lipids, which are also amphiphilic. In aqueoussolutions, amphiphilic block copolymers will self-assemble into various ordered morphologies, such as micelles, vesicles and lamellar phases. Three parameters of block copolymers play important roles in the phase transition between these morphologies, including the molecular weight of the polymer, the mass fraction (f) of each block, and the effective interaction energy between the repeating units in the blocks [34]. PMOXA-PDMS-PMOXA has been widely adopted to form vesicle bilayers for the reconstitution of transmembrane proteins [1,27,29] through self-assembly. In this section, we systematically investigated how the polymer molecular weight and the mass fraction of each block influence the self-assembly, and how the molecular weight of the hydrophobic block effects the AqpZ permeability.
A series of block copolymers PMOXA-PDMS-PMOXA with various molecular weight andhydrophobic/hydrophilic ratio were chosen to prepare proteopolymersomes, as listed in Table 1. The hydrophilic ratio (fhydrophilic) of these polymers ranges from 23.4 to 34.2% in the sequence of P8500 < P2500 < P8800 < P4000 < P5000. Figure 2 shows the morphologies of the self-assemblies without extrusion. It can be seen that all of them form vesicles except for P8500. This result is consistent with previous report in that the fhydrophilic range of block copolymer to form vesicles is between 25 to 40% [35]. With increasing fhydrophilic, vesicle size decreases sequentially as P2500 > P8800 > P4000 > P5000. According to the simulation results from our previous work, larger vesicles are preferable since larger vesicles will generate higher water flux as compared to smaller ones in an AqpZ-incorporated-vesicular membrane [27]. Therefore, block copolymers with fhydrophilic ranging from 25 to 30% are preferable for preparation of AqpZ-incorporated-vesicular membrane.
The vesicle wall thickness is greatly influenced by the molecular weight of the hydrophobic block of PDMS in the PMOXA-PDMS-PMOXA. Figure 3 shows the correlation between the molecular weight of the hydrophobic block and the vesicle wall thickness measured from TEM. It can be seen that, vesicle wall thickness increases from 5.2 nm to 11.6 nm when the molecular weight of the hydrophobic block PDMS increases from 2500 to 8800. A longer hydrophobic chain length leads to a thicker membrane wall and a higher packing density due to chain entanglement, which is consistent with other reports [34]. In addition, the triblock copolymers P4000 and P5000 have methacrylate end groups thatallow for a UV light-induced polymerization. After UV light exposure, the methacrylate end groups distributed at the vesicle surface will be polymerized with neighbouring methacrylate end groups and form a covalent bond shell on the vesicle surface, which will enhance the mechanical stability of vesicles. In Figure 3, the red points refer to the wall thickness of vesicles that are formed from methacrylate-copolymers after UV exposure. It is noted that for vesicles prepared from methacrylate-copolymers, P4000 and P5000, vesicle wall thickness increases after UV polymerization of the methacrylate end groups as compared to vesicles without or before polymerization.
The hydrophobic thickness of the polymer vesicles, as shown in Figure 3,is thicker than that of lipid bilayers, which is 3 nm [36]. When AqpZ is reconstituted into polymer vesicles, there is hydrophobic mismatch between the hydrophobic length of the AqpZ and the hydrophobic thickness of the membrane, as shown in Figure 4. It has been reported that the membrane protein with hydrophobic mismatch towards the neighbouring bilayer will distort the bilayer at the interface, resulting in the bilayer morphology not being aligned correctly with the protein [37]. It has also been reported that the elastic lipid chain distortions are insufficient to compensate fully for the mismatch [38], and the structure and dynamics of protein might change due to this hydrophobic mismatch [39,40]. The stretched or compressed structure of AqpZ might affect water transport behavior of the water channels. In this work, the permeability of AqpZ that reconstituted in these polymers was therefore investigated through the vesicle permeability using stopped-flow spectroscopy.
Figure 5 shows examples of the light scattering intensity curves for blank polymersomes (Figure 5a) and proteopolymersomes (Figure 5b). It can be observed from Figure 5a that with increasing hydrophobic chain length, vesicle size responds slower to the osmotic pressure. When the hydrophobic chain length is above 5000 Da, vesicle size almost does not respond to the osmotic pressure, indicating an extremely slow water diffusion speed across the thick hydrophobic wall and a negligible water permeability of the blank polymersomes. From Figure 5b,it can be observed that all AqpZ reconstituted vesicles shrink more quickly than the blank vesicles under the osmotic pressure. This proves that AqpZ has been successfully reconstituted to maintain its water transport functionality in these polymer vesicles. According to Figure 3,vesicle wall thickness ranges from 5.2 to 11.6 nm, which is much thicker than the lipid bilayer. The stopped-flow results gave us confidence that the hydrophobic mismatch, which is less than 9 nm, will not lead to AqpZ misfolding or denaturation.
Figure 6 shows permeabilities for both types of vesicles (Figure 6a) and each AqpZ unit in proteopolymersomes (Figure 6b). In this work, the molecular weight of the hydrophobic block PDMS ranges from 2500 to 8800 Da. Correspondingly, vesicle wall thickness ranges from 5.2 nm to 11.6 nm. A stretched AqpZ structure might take place due to the hydrophobic mismatch between the AqpZ protein and a thick hydrophobic layer of the vesicle membrane. In order to investigate whether the stretched structure of AqpZ affected the water transport behavior of the water channels, we calculated the water permeability of each AqpZ unit (Pa) in these vesicles. The Pa value ranges from 6.9 to 14 × 10-14 cm3 s-1 which is consistent with Verkman’s results (from 6 to 24 × 10-14 cm3 s-1) [41], indicating that the hydrophobic mismatch, in our experiment range, will not lead to AqpZ misfolding or denaturation. Moreover, from Figure 6b,we find that a thicker vesicle wall leads to a larger Pa value, indicating that the hydrophobic mismatch in our experiment range enhances the water permeability of the AqpZ channel. The reason could be due to the water channel being distortedand expanded to a small extent, forming a “stretched structure” of AqpZ. Further evidence will be needed to confirm this hypothesis of a stretched AqpZ structure in the polymer bilayers.
To investigate the activation energies for water transport in both the polymer bilayers and the AqpZ channels, stopped-flow spectroscopy and light scattering analysis were performed at various temperatures ranging from 278 K to 303 K. Figure 7 was plotted using the derived ln k values against the inverse temperature values, 1/T, where k is the initial rate constant (s-1) of the light scattering intensity signal, and T is the temperature. The observed trends for the ln k values of the blank polymer vesicles and AqpZ-reconstituted polymer vesicles to the variation in experimental temperatures were consistent for all the ABA copolymers used, and exhibited similar linearly decreasing trends. When temperature increases, more heat energy is provided to the water molecules present. The heat energy gained by the water molecules gets converted to kinetic energy, leading to an increase in the rate of transport of the water molecules across the membrane through the AqpZ channels. In addition, higher temperature provides higher kinetic energy to the water molecules, leading to greater frequency and impact of the water molecules against the bilayer structure. Therefore, this gives rise to a greater number of water molecules passing through the bilayer structure through the pores present between the polymers, without going through AqpZ proteins.
As shown in Figure 8,the calculated Arrhenius activation energies for blank polymer bilayers ranges from 6.4 to 52.8 kcal/mol, which is consistent with the reported activation values for water transport across polymer membranes [42]. The high Arrhenius activation energies of blank polymer vesicles indicate that the water transport through polymer bilayers is based on a diffusion-driven mechanism. It can also be observed that higher Arrhenius activation energies were obtained from the polymer vesicles with higher hydrophobic molecular weight, compared to those polymer vesicles with lower hydrophobic molecular weight. The denser packing of the longer hydrophobic chain and the thicker membrane hydrophobic thickness form a larger barrier for diffusion, requiring higher activation energies for water molecules passing through. Arrhenius activation energies for AqpZ reconstituted polymer vesicles range from 2.1 to 6.1 kcal/mol. These lower Arrhenius activation energies indicate that water transport across the AqpZ reconstituted vesicles is channel-mediated. Borgnia et al. reported that the activation energy for AqpZ channel is 3.7 kcal/mol in proteoliposomes [12] and thus our results are comparable to the reported value. In addition, when AqpZ were reconstituted into block copolymers with longer hydrophobic chains, a lower Arrhenius activation energy was required for water molecules to pass through the AqpZ channel. It again implies that the structure of AqpZ channel might be stretched to some extent due to the hydrophobic mismatch, leading to a wider channel for the water molecule to pass through. To confirm this hypothesis, further investigations using x-ray crystallography, NMR spectroscopy and molecular dynamics simulation will be needed.
Figure 9a shows the permeability coefficients of the AqpZ-reconstituted P4000 vesicle in buffer solutions with different pH values. The highest Pf appears near neutral conditions when the pH is 7.5. With increasing concentration of H+, the Pf greatly decreased at pH of 5.5, and increased again in the strongly acidic environment with pH less than 3.5. On the other hand, with increasing concentration of OH- in the vesicle solution, the Pf value also greatly decreased at pH of 8.9 and followed by a slight increase at the strongly basic environment with a pH of more than 10. Further, we calculated the osmotic permeability of AqpZ channel (Pa) based on the Pf value. As shown in Figure 9b,the Pa versus the pH shows the same trend as the vesicle permeability coefficient (Pf). This shows that thewater filtration mechanism of AqpZ is significantly affected by the ions of H+ and OH-.
The observed trends for the regulation in the osmotic permeability of the AqpZ-ABA vesicles (Figure 9a) and the individual AqpZ proteins (Figure 9b) are similar with respect to the variation in pH. The tendency of the osmotic permeability to decrease with increasing pH values may be attributed to the structure of AqpZ. Near the constriction of the AqpZ hydrophobic channel, there are histidine (H) and arginine (R) residues present in the AqpZ monomer loops at positions H180 and R195 respectively that provide the positive charges required in the water transport mechanism of AqpZ [14,15]. Histidine has an overall pI value of 7.6 with their imidazole side chains having a pKa of about 6.0, while arginine has an overall pI value of 10.8 with their guanidinium side chains having a pKa of 12.5. Hence, the positive charges present on the residues will change with pH due to the effects of protonation.
The change in the protonation status of the -COOH terminal group of the amino acid residues as pH changes, may have an effect on the water-pore interaction and the formation of the single file configuration of water molecules passing through the AqpZ channel. Thus AqpZ water transport efficiency was affected since the separation capabilities of AqpZ stems from the formation of thesingle file of water molecule, which prohibits proton translocation and is dependent on the positive charges present at positions H180 and R195 [14,15].
There is an increasing pressure to innovate cheaper forms of membrane technologies to address the issue of water scarcity. Biomimetic membrane technologies utilizing aquaporin is an attractive alternative that can carry out filtration at high capacities using a lower pressure gradient. For AqpZ to be exploited successfully in membrane filtration, an understanding of the factors that influence the osmotic permeability of AqpZ is critical. This study investigated the influences of factors such as pH, temperature, crosslinking and the molecular structure of the ABA tri-block copolymers (PMOXA-PDMS-PMOXA) in which the AqpZ was incorporated, on the osmotic permeability of AqpZ. Results show that the molecular structure of PMOXA-PDMS-PMOXA significantly alters the vesicle morphology and aquaporin functionality. Block copolymers with longer hydrophobic chains form vesicles with thicker hydrophobic walls, resulting in larger hydrophobic mismatch between the protein and the bilayer membrane. The stopped flow results show that the osmotic permeability of AqpZ has improved when reconstituted in a bilayer with a larger hydrophobic thickness. The Arrhenius activation energies for water transport across the AqpZ channel showa decreasing trend with increasing hydrophobic thickness of the bilayers, indicating a “stretched structure” of the AqpZ when encountering a lengthening hydrophobic mismatch. In addition, we found that the water filtration mechanism of the AqpZ protein is significantly affected by the ionic concentrations of H+ and OH-. The individual AqpZ exhibits the highest osmotic permeability in neutral solution. The ApqZ osmotic permeability decreased with eitherincreasing concentrations of H+, or increasing concentrations of OH-.
This work was financially supported by Singapore's National Research Foundation (NRF) through the Environment and Water Industry Programme Office (EWIPO) EWI projects, 1102-IRIS-13-01 and 1102-IRIS-13-02 as well as the NUS grant R706000022279. The authors would like to thank Prof. T. S. Chung, Drs Q. Lin, H. Wang, H. Zhou, L. Wang for their suggestions and help with this work.
All authors declare no conflicts of interest in this paper.
[1] | Julien CM, Mauger A, Vijh A, et al. (2016) Lithium Batteries, Switzerland: Springer, Cham. |
[2] |
Vetter J, Novák P, Wagner MR, et al. (2005) Ageing mechanisms in lithium-ion batteries. J Power Sources 147: 269–281. doi: 10.1016/j.jpowsour.2005.01.006
![]() |
[3] |
Tröltzsch U, Kanoun O, Tränkler HR (2006) Characterizing aging effects of lithium ion batteries by impedance spectroscopy. Electrochim Acta 51: 1664–1672. doi: 10.1016/j.electacta.2005.02.148
![]() |
[4] |
Kiziltas-Yavuz N, Herklotz M, Hashem AM, et al. (2013) Synthesis, structural, magnetic and electrochemical properties of LiNi1/3Mn1/3Co1/3O2 prepared by a sol-gel method using table sugar as chelating agent. Electrochim Acta 113: 313–321. doi: 10.1016/j.electacta.2013.09.065
![]() |
[5] |
Birkl CR, Roberts MR, McTurk E, et al. (2017) Degradation diagnostics for lithium ion cells. J Power Sources 341: 373–386. doi: 10.1016/j.jpowsour.2016.12.011
![]() |
[6] |
Cabana J, Kwon BJ, Hu L (2018) Mechanisms of degradation and strategies for the stabilization of cathode–electrolyte interfaces in Li-ion batteries. Accounts Chem Res 51: 299–308. doi: 10.1021/acs.accounts.7b00482
![]() |
[7] |
Xu Z, Rahman MM, Mu L, et al. (2018) Chemomechanical behaviors of layered cathode materials in alkali metal ion batteries. J Mater Chem A 6: 21859–21884. doi: 10.1039/C8TA06875E
![]() |
[8] |
Zheng JM, Gu M, Xiao J, et al. (2014) Functioning mechanism of AlF3 coating on the Li- and Mn-rich cathode materials. Chem Mater 26: 6320–6327. doi: 10.1021/cm502071h
![]() |
[9] |
Tasaki K, Kanda K, Nakamura S, et al. (2003) Decomposition of LiPF6 and stability of PF5 in Li-ion battery electrolytes. J Electrochem Soc 150: A1628–A1636. doi: 10.1149/1.1622406
![]() |
[10] |
Myung ST, Izumi K, Komaba S, et al. (2005) Role of alumina coating on Li-Ni-Co-Mn-O particles as positive electrode material for lithium-ion batteries. Chem Mater 17: 3695–3704. doi: 10.1021/cm050566s
![]() |
[11] |
Chen Z, Qin Y, Amine K, et al. (2010) Role of surface coating on cathode materials for lithium-ion batteries. J Mater Chem 20: 7606–7612. doi: 10.1039/c0jm00154f
![]() |
[12] |
Mauger A, Julien CM (2014) Surface modifications of electrode materials for lithium-ion batteries: status and trends. Ionics 20: 751–787. doi: 10.1007/s11581-014-1131-2
![]() |
[13] | Jin X, Xu Q, Liu H, et al. (2014) Excellent rate capability of Mg doped Li[Li0.2Ni0.13Co0.13Mn0.54]O2 cathode material for lithium-ion battery. Electrochim Acta 136: 19–26. |
[14] | Zheng J, Wu X, Yang Y (2013) Improved electrochemical performance of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode material by fluorine incorporation. Electrochim Acta 105: 200–208. |
[15] |
Zhang SS (2006) A review on electrolyte additives for lithium-ion batteries. J Power Sources 162: 1379–1394. doi: 10.1016/j.jpowsour.2006.07.074
![]() |
[16] |
Li M, Zhou Y, Wu X, et al. (2018) The combined effect of CaF2 coating and La-doping on electrochemical performance of layered lithium-rich cathode material. Electrochim Acta 275: 18–24. doi: 10.1016/j.electacta.2018.04.077
![]() |
[17] | Lu Y, Shi S, Yang F, et al. (2018) Mo-doping for improving the ZrF4 coated-Li[Li0.2Mn0.54Ni0.13Co0.13]O2 as high performance cathode materials in lithium-ion batteries. J Alloy Compd 767: 23–33. |
[18] |
Hashem AMA, Abdel-Ghany AE, Eid AE, et al. (2011) Study of the surface modification of LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion battery. J Power Sources 196: 8632–8637. doi: 10.1016/j.jpowsour.2011.06.039
![]() |
[19] |
Yang ZX, Qiao QD, Yang WS (2011) Improvement of structural and electrochemical properties of commercial LiCoO2 by coating with LaF3. Electrochim Acta 56: 4791–4796. doi: 10.1016/j.electacta.2011.03.017
![]() |
[20] | Sun SH, Kim SB, Park YJ (2009) The effects of LaF3 coating on the electrochemical property of Li[Ni0.3Co0.4Mn0.3]O2 cathode material. B Korean Chem Soc 30: 2584–2588. |
[21] | Xie QL, Hu ZB, Zhao CH, et al. (2015) LaF3-coated Li[Li0.2Mn0.56Ni0.16Co0.08]O2 as cathode material with improved electrochemical performance for lithium ion batteries. RSC Adv 5: 50859–50864. |
[22] |
Lee HJ, Park YJ (2013) Interface characterization of MgF2-coated LiCoO2 thin films. Solid State Ionics 230: 86–91. doi: 10.1016/j.ssi.2012.08.003
![]() |
[23] |
Shi SJ, Tu JP, Mai YJ, et al. (2012) Structure and electrochemical performance of CaF2 coated LiMn1/3Ni1/3Co1/3O2 cathode material for Li-ion batteries. Electrochim Acta 83: 105–112. doi: 10.1016/j.electacta.2012.08.029
![]() |
[24] | Liu X, Liu J, Huang T, et al. (2013) CaF2-coated Li1.2Mn0.54Ni0.13Co0.13O2 as cathode materials for Li-ion batteries. Electrochim Acta 109: 52–58. |
[25] | Zhang X, Yang Y, Sun S, et al. (2016) Multifunctional ZrF4 nanocoating for improving lithium storage performances in layered Li[Li0.2Ni0.17Co0.07Mn0.56]O2. Solid State Ionics 284: 7–13. |
[26] |
Li JG, Wang L, Zhang Q, et al. (2009) Electrochemical performance of SrF2-coated LiMn1/3Ni1/3Co1/3O2 cathode materials for Li-ion batteries. J Power Sources 190: 149–153. doi: 10.1016/j.jpowsour.2008.08.011
![]() |
[27] | Liu BL, Zhang Z, Wan J, et al. (2017) Improved electrochemical properties of YF3-coated Li1.2Mn0.54Ni0.13Co0.13O2 as cathode for Li-ion batteries. Ionics 23: 1365–1374. |
[28] |
Sun YK, Cho SW, Myung ST, et al. (2007) Effect of AlF3 coating amount on high voltage cycling performance of LiCoO2. Electrochim Acta 53: 1013–1019. doi: 10.1016/j.electacta.2007.08.032
![]() |
[29] |
Wang Z, Wang Z, Guo H, et al. (2014) Enhanced high-voltage electrochemical performance of LiCoO2 coated with ZrOxFy. Mater Lett 123: 93–96. doi: 10.1016/j.matlet.2014.03.021
![]() |
[30] | Lee KS, Myung ST, Amine K, et al. (2009) Dual functioned BiOF-coated Li[Li0.1Al0.05Mn1.85]O4 for lithium batteries. J Mater Chem 19: 1995–2005. |
[31] | Hao Y, Yand F, Luo D, et al. (2018) Improved electrochemical performances of yttrium oxyfluoride-coated Li[Li0.2Mn0.54Ni0.13Co0.13]O2 for lithium ion batteries. J Energy Chem 27: 1239–1246. |
[32] |
Bai Y, Jiang K, Sun S, et al. (2014) Performance improvement of LiCoO2 by MgF2 surface modification and mechanism exploration. Electrochim Acta 134: 347–354. doi: 10.1016/j.electacta.2014.04.155
![]() |
[33] |
Shi SJ, Tu JP, Tang YY, et al. (2013) Enhanced electrochemical performance of LiF-modified LiMn1/3Ni1/3Co1/3O2 cathode materials for Li-ion batteries. J Power Sources 225: 338–346. doi: 10.1016/j.jpowsour.2012.10.065
![]() |
[34] |
Chen Q, Wang Y, Zhang T, et al. (2012) Electrochemical performance of LaF3-coated LiMn2O4 cathode materials for lithium ion batteries. Electrochim Acta 83: 65–72. doi: 10.1016/j.electacta.2012.08.025
![]() |
[35] |
Amatucci GG, Pereira N (2007) Fluoride based electrode materials for advanced energy storage devices. J Fluorine Chem 128: 243–262. doi: 10.1016/j.jfluchem.2006.11.016
![]() |
[36] |
Cabana J, Monconduit L, Larcher D, et al. (2010) Beyond intercalation-based Li-ion batteries: The state of the art and challenges of electrode materials reacting through conversion reactions. Adv Mater 22: E170–E192. doi: 10.1002/adma.201000717
![]() |
[37] |
Badway F, Cosandey F, Pereira N, et al. (2003) Carbon metal fluoride nanocomposites: High-capacity reversible metal fluoride conversion materials as rechargeable positive electrodes for Li batteries. J Electrochem Soc 150: A1318–A1327. doi: 10.1149/1.1602454
![]() |
[38] |
Bervas M, Badway F, Klein LC, et al. (2005) Bismuth fluoride nanocomposite as a positive electrode material for rechargeable lithium batteries. Electrochem Solid-State Lett 8: A179–A183. doi: 10.1149/1.1861040
![]() |
[39] |
Owen N, Zhang Q (2017) Investigations of aluminum fluoride as a new cathode material for lithium-ion batteries. J Appl Electrochem 47: 417–431. doi: 10.1007/s10800-017-1049-2
![]() |
[40] | Le Bail A, Calvayrac F (2006) Hypothetical AlF3 crystal structures. J Solid State Chem 179: 3159–3166. |
[41] |
Navarro JL, Albanesi E, Vidal RA, et al. (2016) A study on the structural, electronic and optical properties of the α-AlF3 compound. Mater Res Bull 83: 615–622. doi: 10.1016/j.materresbull.2016.07.007
![]() |
[42] |
Bridou F, Cuniot-Ponsard M, Desvignes JM, et al. (2010) Experimental determination of optical constants of MgF2 and AlF3 thin films in the vacuum ultra-violet wavelength region (60–124 nm), and its application to optical designs. Opt Commun 283: 1351–1358. doi: 10.1016/j.optcom.2009.11.062
![]() |
[43] | Myung ST, Lee KS, Yoon CS, et al. (2010) Effect of AlF3 coating on thermal behavior of chemically delithiated Li0.35[Ni1/3Co1/3Mn1/3]O2. J Phys Chem C 114: 4710–4718. |
[44] |
Kemnitz E, Menz DH (1998) Fluorinated metal oxides and metal fluorides as heterogeneous catalysts. Prog Solid State Ch 26: 97–153. doi: 10.1016/S0079-6786(98)00003-X
![]() |
[45] |
Sun YK, Lee MJ, Yoon CS, et al. (2012) The role of AlF3 coatings in improving electrochemical cycling of Li-enriched nickel-manganese oxide electrodes for Li-ion batteries. Adv Mater 24: 1192–1196. doi: 10.1002/adma.201104106
![]() |
[46] |
Kanamura K, Okagawa T, Takehara ZI (1995) Electrochemical oxidation of propylene carbonate (containing various salts) on aluminum electrodes. J Power Sources 57: 119–123. doi: 10.1016/0378-7753(95)02265-1
![]() |
[47] |
Morita M, Shibata T, Yoshimoto N, et al. (2002) Anodic behavior of aluminum in organic solutions with different electrolytic salts for lithium ion batteries. Electrochim Acta 47: 2787–2793. doi: 10.1016/S0013-4686(02)00164-0
![]() |
[48] |
Ma T, Xu GL, Li Y, et al. (2017) Revisiting the corrosion of the aluminum current collector in lithium-ion batteries. J Phys Chem Lett 8: 1072–1077. doi: 10.1021/acs.jpclett.6b02933
![]() |
[49] |
Kawamura T, Tanaka T, Egashira M, et al. (2005) Methyl difluoroacetate inhibits corrosion of aluminum cathode current collector for lithium ion cells. Electrochem Solid-State Lett 8: A459–A463. doi: 10.1149/1.1993367
![]() |
[50] | Hennessy J, Jewell AD, Balasubramanian K, et al. (2016) Ultraviolet optical properties of aluminum fluoride thin films deposited by atomic layer deposition. J Vac Sci Technol A 34: 01A120. |
[51] |
Lee Y, DuMont JW, Cavanagh AS, et al. (2015) Atomic layer deposition of AlF3 using trimethylaluminum and hydrogen fluoride. J Phys Chem C 119: 14185–14194. doi: 10.1021/acs.jpcc.5b02625
![]() |
[52] | Mane AU, Elam JW, Park JS, et al. (2016) Metal fluoride passivation coatings prepared by atomic layer deposition on LiCoO2 for Li-ion batteries. US Patent 2016/0260962A1. |
[53] |
Zhou Y, Lee Y, Sun H, et al. (2017) Coating solution for high-voltage cathode: AlF3 atomic layer deposition for freestanding LiCoO2 electrodes with high energy density and excellent flexibility. ACS Appl Mater Inter 9: 9614–9619. doi: 10.1021/acsami.6b15628
![]() |
[54] |
Pang S, Wang Y, Chen T, et al. (2016) The effect of AlF3 modification on the physicochemical and electrochemical properties of Li-rich layered oxide. Ceram Int 42: 5397–5402. doi: 10.1016/j.ceramint.2015.12.076
![]() |
[55] |
Jackson DHK (2016) Optimizing AlF3 atomic layer deposition using trimethylaluminum and TaF5: Application to high voltage Li-ion battery cathodes. J Vac Sci Technol A 34: 031503. doi: 10.1116/1.4943385
![]() |
[56] |
Lee HJ, Kim SB, Park YJ (2012) Enhanced electrochemical properties of fluoride-coated LiCoO2 thin films. Nanoscale Res Lett 7: 16. doi: 10.1186/1556-276X-7-16
![]() |
[57] |
Hao S, Wolverton C (2013) Lithium transport in amorphous Al2O3 and AlF3 for discovery of battery coatings. J Phys Chem C 117: 8009–8013. doi: 10.1021/jp311982d
![]() |
[58] |
Jung SC, Han YK (2013) How do Li atoms pass through the Al2O3 coating layer during lithiation in Li-ion batteries? J Phys Chem Lett 4: 2681–2685. doi: 10.1021/jz401231e
![]() |
[59] |
Xu S, Jacobs RM, Nguyen HM, et al. (2015) Lithium transport through lithium-ion battery cathode coatings. J Mater Chem A 3: 17248–17272. doi: 10.1039/C5TA01664A
![]() |
[60] |
Riley LA, Van Atta S, Cavanagh AS, et al. (2011) Electrochemical effects of ALD surface modification on combustion synthesized LiNi1/3Mn1/3Co1/3O2 as a layered-cathode material. J Power Sources 196: 3317–3324. doi: 10.1016/j.jpowsour.2010.11.124
![]() |
[61] | Cheng HM, Wang FM, Chu JP, et al. (2012) Enhanced cyclability in lithium ion batteries: resulting from atomic layer deposition of Al2O3 or TiO2 on LiCoO2 electrodes. J Phys Chem C 116: 7629–7637. |
[62] |
Li X, Liu J, Meng X, et al. (2014) Significant impact on cathode performance of lithium-ion batteries by precisely controlled metal oxide nanocoatings via atomic layer deposition. J Power Sources 247: 57–69. doi: 10.1016/j.jpowsour.2013.08.042
![]() |
[63] | Kim JH, Park MH, Song JH, et al. (2012) Effect of aluminum fluoride coating on the electrochemical and thermal properties of 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 composite material. J Alloy Compd 517: 20–25. |
[64] |
Oi T, Miyauchi K, Uehara K (1982) Electrochromism of WO3/LiAlF4/LiIn thin-film overlayers. J Appl Phys 53: 1823. doi: 10.1063/1.330597
![]() |
[65] |
Stechert TR, Rushton MJD, Grimes RW, et al. (2012) Predicted structure, thermo-mechanical properties and Li ion transport in LiAlF4 glass. J Non-Cryst Solids 358: 1917–1923. doi: 10.1016/j.jnoncrysol.2012.05.044
![]() |
[66] |
Xie J, Sendek AD, Cubuk ED, et al. (2017) Atomic layer deposition of stable LiAlF4 lithium ion conductive interfacial layer for stable cathode cycling. ACS Nano 11: 7019–7027. doi: 10.1021/acsnano.7b02561
![]() |
[67] |
Oi T (1984) Ionic conductivity of LiF thin films containing di- and trivalent metal fluorides. Mater Res Bull 19: 451–457. doi: 10.1016/0025-5408(84)90105-3
![]() |
[68] | Goodenough JB, Kim Y (2010) Challenges for rechargeable Li batteries. Chem Mater 22: 587–603. |
[69] |
Goodenough JB, Park KS (2013) The Li-ion rechargeable battery: A perspective. J Am Chem Soc 135: 1167–1176. doi: 10.1021/ja3091438
![]() |
[70] |
Goodenough JB (2014) Electrochemical energy storage in a sustainable modern society. Energ Environ Sci 7: 14–18. doi: 10.1039/C3EE42613K
![]() |
[71] |
Sun YK, Han JM, Myung ST, et al. (2006) Significant improvement of high voltage cycling behavior AlF3-coated LiCoO2 cathode. Electrochem Commun 8: 821–826. doi: 10.1016/j.elecom.2006.03.040
![]() |
[72] |
Sun YK, Yoon CS, Myung ST, et al. (2009) Role of AlF3 coating on LiCoO2 particles during cycling to cutoff voltage above 4.5 V. J Electrochem Soc 156: A1005–A1010. doi: 10.1149/1.3236501
![]() |
[73] |
Aboulaich A, Ouzaoult K, Faqir H, et al. (2016) Improving thermal and electrochemical performances of LiCoO2 cathode at high cut-off charge potentials by MF3 (M = Ce, Al) coating. Mater Res Bull 73: 362–368. doi: 10.1016/j.materresbull.2015.09.020
![]() |
[74] | Sun YK, Park BC, Yashiro H (2008) Improvement of the electrochemical properties of Li[Ni0.5Mn0.5]O2 by AlF3 coating. J Electrochem Soc 155: A705–A710. |
[75] | Abdel-Ghany A, El-Tawil RS, Hashem AM, et al. (2019) Improved electrochemical performance of LiNi0.5Mn0.5O2 by Li-enrichment and AlF3 coating. Materialia 5: 100207. |
[76] | Woo SU, Yoon CS, Amine K, et al. (2007) Significant improvement of electrochemical performance of AlF3-coated Li[Ni0.8Co0.1Mn0.1]O2 cathode materials. J Electrochem Soc 154: A1005–A1009. |
[77] |
Sun YK, Cho SW, Lee SW, et al. (2007) AlF3-coating to improve high voltage cycling performance of Li[Ni1 ∕ 3Co1 ∕ 3Mn1 ∕ 3]O2 cathode materials for lithium secondary batteries. J Electrochem Soc 154: A168–A172. doi: 10.1149/1.2422890
![]() |
[78] |
Lee KS, Myung ST, Kim DW, et al. (2011) AlF3-coated LiCoO2 and Li[Ni1/3Co1/3Mn1/3]O2 blend composite cathode for lithium ion batteries. J Power Sources 196: 6974–6977. doi: 10.1016/j.jpowsour.2010.11.014
![]() |
[79] |
Park BC, Kim HB, Myung ST, et al. (2008) Improvement of structural and electrochemical properties of AlF3-coated Li[Ni1/3Co1/3Mn1/3]O2 cathode materials on high voltage region. J Power Sources 178: 826–831. doi: 10.1016/j.jpowsour.2007.08.034
![]() |
[80] | Wang HY, Tang AD, Huang KL, et al. (2010) Uniform AlF3 thin layer to improve rate capability of LiNi1/3Co1/3 Mn1/3O2 material for Li-ion batteries. T Nonferr Metal Soc 20: 803–808. |
[81] |
Shi SJ, Tu JP, Tang YY, et al. (2013) Enhanced electrochemical performance of LiF-modified LiMn1/3Ni1/3Co1/3O2 cathode materials for Li-ion batteries. J Power Sources 225: 338–346. doi: 10.1016/j.jpowsour.2012.10.065
![]() |
[82] | Lin H, Yang Y (2009) Structural characterization and electrochemical performance of AlF3-coated LiNi0.45Mn0.45Co0.10O2 as cathode materials for lithium ion batteries. Acta Chim Sinica 67: 104–108. |
[83] | Myung ST, Lee KS, Yoon CS, et al. (2010) Effect of AlF3 coating on thermal behavior of chemically delithiated Li0.35[Ni1/3Co1/3Mn1/3]O2. J Phys Chem C 114: 4710–4718. |
[84] | Song HG, Park YJ (2012) LiLaPO4-coated Li[Ni0.5Co0.2Mn0.3]O2 and AlF3-coated Li[Ni0.5Co0.2Mn0.3]O2 blend composite for lithium ion batteries. Mater Res Bull 47: 2843–2846. |
[85] | Yang K, Fan LZ, Guo J, et al. (2012) Significant improvement of electrochemical properties of AlF3-coated LiNi0.5Co0.2Mn0.3O2 cathode materials. Electrochim Acta 63: 363–368. |
[86] | Amalraj F, Talianker M, Markovsky B, et al. (2013) Studies of Li and Mn-rich Lix[MnNiCo]O2 electrodes: electrochemical performance, structure, and the effect of the aluminum fluoride coating. J Electrochem Soc 160: A2220–A2233. |
[87] | Sun S, Yin Y, Wan N, et al. (2015) AlF3 surface‐coated Li[Li0.2Ni0.17Co0.07Mn0.56]O2 nanoparticles with superior electrochemical performance for lithium‐ion batteries. ChemSusChem 8: 2544–2550. |
[88] | Xiao QC, Sun KL, Zhang HL, et al. (2014) High performance Li1.2(Mn0.54Co0.13Ni0.13)O2 with AlF3/carbon hybrid shell for lithium ion batteries. Mater Technol 29: A70–A76. |
[89] | Deng H, Belharouak I, Yoon CS, et al. (2010) High temperature performance of surface-treated Li1.1(Ni0.15Co0.1Mn0.55)O1.95 layered oxide. J Electrochem Soc 157: A1035–A1039. |
[90] | Zhao T, Chen S, Chen R, et al. (2014) The positive roles of integrated layered-spinel structures combined with nanocoating in low-cost Li-rich cathode Li[Li0.2Fe0.1Ni0.15Mn0.55]O2 for lithium-ion batteries. ACS Appl Mater Inter 6: 21711–21720. |
[91] | Li GR, Feng X, Ding Y, et al. (2012) AlF3-coated Li(Li0.17Ni0.25Mn0.58)O2 as cathode material for Li-ion batteries. Electrochim Acta 78: 308–315. |
[92] | Ding J, Lu Z, Wu M, et al. (2017) Preparation and performance characterization of AlF3 as interface stabilizer coated Li1.24Ni0.12Co0.12Mn0.56O2 cathode for lithium-ion batteries. Appl Surf Sci 406: 21–29. |
[93] |
Rosina KJ, Jiang M, Zeng D, et al. (2012) Structure of aluminum fluoride coated Li[Li1/9Ni1/3Mn5/9]O2 cathodes for secondary lithium-ion batteries. J Mater Chem 22: 20602–20610. doi: 10.1039/c2jm34114j
![]() |
[94] | Wang XY, Ye XH, Zhi XK, et al. (2013) Effects of AlF3 coating on the electrochemical performance of Li1.2Mn0.52Ni0.2Co0.08O2 cathode materials. Chinese J Inorg Chem 29: 774–778. |
[95] | Li Y, Liu KY, Lü MY, et al. (2014) Synthesis, characterization and electrochemical performance of AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 as cathode for Li-ion battery. T Nonferr Metal Soc 24: 3534–3540. |
[96] |
Park K, Park JH, Hong SG, et al. (2016) Induced AlF3 segregation for the generation of reciprocal Al2O3 and LiF coating layer on self-generated LiMn2O4 surface of over-lithiated oxide based Li-ion battery. Electrochim Acta 222: 830–837. doi: 10.1016/j.electacta.2016.11.044
![]() |
[97] |
Zhao S, Sun B, Yan K, et al. (2018) Aegis of lithium-rich cathode materials via heterostructured LiAlF4 coating for high-performance lithium-ion batteries. ACS Appl Mater Inter 10: 33260–33268. doi: 10.1021/acsami.8b11471
![]() |
[98] |
Chen D, Tu W, Chen M, et al. (2016) Synthesis and performances of Li-rich@AlF3@graphene as cathode of lithium ion battery. Electrochim Acta 193: 45–53. doi: 10.1016/j.electacta.2016.02.043
![]() |
[99] | Zhu L, Liu Y, Wu W, et al. (2015) Surface fluorinated LiNi0.8Co0.15Al0.05O2 as a positive electrode material for lithium ion batteries. J Mater Chem A 3: 151456–15162. |
[100] | Kim HB, Park BC, Myung ST, et al. (2008) Electrochemical and thermal characterization of AlF3-coated Li[Ni0.8Co0.15Al0.05]O2 cathode in lithium-ion cells. J Power Sources 179: 347–350. |
[101] | Park BC, Kim HB, Bang HJ, et al. (2008) Improvement of electrochemical performance of Li[Ni0.8Co0.15Al0.05]O2 cathode materials by AlF3 coating at various temperatures. Ind Eng Chem Res 47: 3876–3882. |
[102] | Zhang L, Luo F, Wang J, et al. (2014) Surface coating and electrochemical properties of LiNi0.8Co0.15Al0.05O2 cathode in lithium-ion cells. Adv Mater Res 1058: 317–320. |
[103] | Lee SH, Yoon CS, Amine K, et al. (2013) Improvement of long-term cycling performance of Li[Ni0.8Co0.15Al0.05]O2 by AlF3 coating. J Power Sources 234: 201–207. |
[104] | Lee DJ, Lee KS, Myung ST, et al. (2011) Improvement of electrochemical properties of Li1.1Mn1.85Al0.05O4 achieved by an AlF3 coating. J Power Sources 196: 1353–1357. |
[105] |
Liu H, Tang D (2009) The effect of nanolayer AlF3 coating on LiMn2O4 cycle life in high temperature for lithium secondary batteries. Russ J Electrochem 45: 762–764. doi: 10.1134/S1023193509070088
![]() |
[106] |
Tron A, Park YD, Mun J (2016) AlF3-coated LiMn2O4 as cathode material for aqueous rechargeable lithium battery with improved cycling stability. J Power Sources 325: 360–364. doi: 10.1016/j.jpowsour.2016.06.049
![]() |
[107] |
Liu Y, Lv J, Fei Y, et al. (2013) Improvement of storage performance of LiMn2O4/graphite battery with AlF3-coated LiMn2O4. Ionics 19: 1241–1246. doi: 10.1007/s11581-013-0853-x
![]() |
[108] |
Wang MS, Wang J, Zhang J, et al. (2015) Improving electrochemical performance of spherical LiMn2O4 cathode materials for lithium ion batteries by Al-F codoping and AlF3 surface coating. Ionics 21: 27–35. doi: 10.1007/s11581-014-1164-6
![]() |
[109] | Zhu Z, Cai F, Yu J (2016) Improvement of electrochemical performance for AlF3-coated Li1.3Mn4/6Ni1/6Co1/6O2.40 cathode materials for Li-ion batteries. Ionics 22: 1353–1359. |
[110] | Wu Q, Yin Y, Sun S, et al. (2015) Novel AlF3 surface modified spinel LiMn1.5Ni0.5O4 for lithium-ion batteries: performance characterization and mechanism exploration. Electrochim Acta 158: 73–80. |
[111] | Li J, Zhang Y, Li J, et al. (2011) AlF3 coating of LiNi0.5Mn1.5O4 for high-performance Li-ion batteries. |
[112] |
Ke X, Zhao Z, Liu J, et al. (2016) Spinel oxide cathode material for high power lithium ion batteries for electrical vehicles. Energy Procedia 88: 689–692. doi: 10.1016/j.egypro.2016.06.099
![]() |
[113] | Ochsner A, Murch GE, Shokuhfar A, et al. (2009) Improvement of the electrochemical properties in nano-sized Al2O3 and AlF3-coated LiFePO4 cathode materials. Defect Diffusion Forum 297–301: 906–911. |
[114] |
Song GM, Wu Y, Liu G, et al. (2009) Influence of AlF3 coating on the electrochemical properties of LiFePO4/graphite Li-ion batteries. J Alloy Compd 487: 214–217. doi: 10.1016/j.jallcom.2009.06.153
![]() |
[115] |
Tron A, Jo YN, Oh SH, et al. (2017) Surface modification of the LiFePO4 cathode for the aqueous rechargeable lithium ion battery. ACS Appl Mater Inter 9: 12391–12399. doi: 10.1021/acsami.6b16675
![]() |
[116] |
Wang Y, Qiu J, Yu Z, et al. (2018) AlF3-modified LiCoPO4 for an advanced cathode towards high energy lithium-ion battery. Ceram Int 44: 1312–1320. doi: 10.1016/j.ceramint.2017.08.084
![]() |
[117] |
Ding F, Xu W, Choi D, et al. (2012) Enhanced performance of graphite anode materials by AlF3 coating for lithium-ion batteries. J Mater Chem 22: 12745–12751. doi: 10.1039/c2jm31015e
![]() |
[118] |
Xu W, Chen X, Wang W, et al. (2013) Simply AlF3-treated Li4Ti5O12 composite anode materials for stable and ultrahigh power lithium-ion batteries. J Power Sources 236: 169–174. doi: 10.1016/j.jpowsour.2013.02.055
![]() |
[119] |
Li W, Li X, Chen M, et al. (2014) AlF3 modification to suppress the gas generation of Li4Ti5O12 composite anode battery. Electrochim Acta 139: 104–110. doi: 10.1016/j.electacta.2014.07.017
![]() |
[120] | Liang G, Pillai AS, Peterson VK, et al. (2018) Effect of AlF3-coated Li4Ti5O12 on the performance and function of the LiNi0.5Mn1.5O4||Li4Ti5O12 full battery-An in operando neutron powder diffraction study. Front Energy Res 6: 89. |
[121] | Kim JW, Kim DH, Oh DY, et al. (2015) Surface chemistry of LiNi0.5Mn1.5O4 particles coated by Al2O3 using atomic layer deposition for lithium-ion batteries. J Power Sources 274: 1254–1262. |
[122] | Han JM, Myung ST, Cho SW, et al. (2006) Significant of AlF3-coated LiCoO2 cathode in high voltage cycling. Extended Abstract of the 210th ECS Meeting, Cancun, Mexico. |
[123] | Makimura Y, Ohzuku T (2003) Lithium insertion material of LiNi1/2Mn1/2O2 for advanced lithium-ion batteries. J Power Sources 119–121: 156–160. |
[124] | Lin H, Zheng J, Yang Y (2010) The effects of quenching treatment and AlF3 coating on LiNi0.5Mn0.5O2 cathode materials for lithium-ion battery. Mater Chem Phys 119: 519–523. |
[125] |
Amalraj F, Sclar H, Shilina Y, et al. (2018) Horizons for Li-ion batteries relevant to electro-mobility: high-specific-energy cathodes and chemically active separators. Adv Mater 30: 1801348. doi: 10.1002/adma.201801348
![]() |
[126] | Zhao F, Mu D, Hou X, et al. (2015) Co-effect of AlF3 and MgF2 on the electrochemical performance of LiNi0.5Mn0.3Co0.2O2 cathode material under high voltage. Adv Mater Res 1088: 327–331. |
[127] |
Nayak PK, Erickson EM, Schipper F, et al. (2018) Review on challenges and recent advances in the electrochemical performance of high capacity Li- and Mn-rich cathode materials for Li-ion batteries. Adv Energy Mater 8: 1702397. doi: 10.1002/aenm.201702397
![]() |
[128] |
Schipper F, Nayak PK, Erickson EM, et al. (2017) Studies of cathode materials for lithium-ion batteries: recent progress and new challenges. Inorganics 5: 32. doi: 10.3390/inorganics5020032
![]() |
[129] |
Li H, Cormier M, Zhang N, et al. (2019) Is cobalt needed in Ni-rich positive electrode materials for lithium ion batteries? J Electrochem Soc 166: A429–A439. doi: 10.1149/2.1381902jes
![]() |
[130] | Park J, Seo JH, Plett G, et al. (1993) Numerical simulation of the effect of the dissolution of LiMn2O4 particles on Li-ion battery performance. Electrochem Solid-State Lett 14: A14–A18. |
[131] |
Oh RG, Hong JE, Yang WG, et al. (2015) Effects of Al2O3 and AlF3 coating on the electrochemical performance of Li3V2(PO4)3/C cathode material in lithium ion batteries. Solid State Ionics 283: 131–136. doi: 10.1016/j.ssi.2015.10.004
![]() |
[132] | Hovington P, Lagacé M, Guerfi A, et al. (2015) New lithium metal polymer solid state battery for an ultrahigh energy: nano C-LiFePO4 versus nano Li1.2V3O8. Nano Lett 15: 2671–2678. |
[133] |
Wang H, Yu Y, Jin G, et al. (2013) AlF3 coated LiV3O8 nanosheets with significantly improved cycling stability as cathode material for Li-ion battery. Solid State Ionics 236: 37–42. doi: 10.1016/j.ssi.2013.01.021
![]() |
[134] |
Julien CM, Mauger A (2018) In situ Raman analyses of electrode materials for Li-ion batteries. AIMS Mater Sci 5: 650–698. doi: 10.3934/matersci.2018.4.650
![]() |
[135] |
Julien CM (2000) 4-volt cathode materials for rechargeable lithium batteries wet-chemistry synthesis, structure and electrochemistry. Ionics 6: 30–46. doi: 10.1007/BF02375545
![]() |
[136] | Julien CM, Massot M (2003) Lattice vibrations of materials for lithium rechargeable batteries III. Lithium manganese oxides. Mat Sci Eng B-Adv 100: 69–78. |
[137] |
Gross U, Rüdiger S, Kemnitz E, et al. (2007) Vibrational analysis study of aluminum trifluoride phases. J Phys Chem A 111: 5813–5819. doi: 10.1021/jp072388r
![]() |
[138] |
Boulard B, Jacoboni C, Rousseau M (1989) Raman spectroscopy vibrational analysis of octahedrally coordinated fluorides: Application to transition metal fluoride glasses. J Solid State Chem 80: 17–31. doi: 10.1016/0022-4596(89)90027-3
![]() |
[139] |
Makarowicz A, Bailey CL, Weiher N, et al. (2009) Electronic structure of Lewis acid sites on high surface area aluminium fluorides: a combined XPS and ab initio investigation. Phys Chem Chem Phys 11: 5664–5673. doi: 10.1039/b821484k
![]() |
[140] |
Tatara R, Karayaylali P, Yu Y, et al. (2019) The effect of electrode-electrolyte interface on the electrochemical impedance spectra for positive electrode in Li-ion battery. J Electrochem Soc 166: A5090–A5098. doi: 10.1149/2.0121903jes
![]() |
[141] |
Kendig M, Scully J (1990) Basic aspects of electrochemical impedance application for the life prediction of organic coatings on metals. Corrosion 46: 22–29. doi: 10.5006/1.3585061
![]() |
[142] |
Fletcher S (1994) Tables of degenerate electrical networks for use in the equivalent-circuit analysis of electrochemical systems. J Electrochem Soc 141: 1823–1826. doi: 10.1149/1.2055011
![]() |
[143] | Zheng JM, Zhang ZR, Wu XB, et al. (2008) The effects of AlF3 coating on the performance of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 positive electrode material for lithium-ion battery. J Electrochem Soc 155: A775–A782. |
[144] |
Li D, Sasaki Y, Kobayakawa K, et al. (2006) Preparation and electrochemical characteristics of LiNi1/3Mn1/3Co1/3O2 coated with metal oxides coating. J Power Sources 160: 1342–1348. doi: 10.1016/j.jpowsour.2006.02.080
![]() |
[145] | Kang SH, Amine K (2007) Layered cathode materials for lithium ion rechargeable batteries. US Patent 7,205,072B2. |
[146] |
Gallagher KG, Nelson PA, Dees DW (2011) Simplified calculation of the area specific impedance for battery design. J Power Sources 196: 2289–2297. doi: 10.1016/j.jpowsour.2010.10.020
![]() |
[147] |
Belharouak I, Sun YK, Liu J, et al. (2003) Li(Ni1/3Co1/3Mn1/3)O2 as a suitable cathode for high power applications. J Power Sources 123: 247–252. doi: 10.1016/S0378-7753(03)00529-9
![]() |
[148] | Son JT (2008) Improvement of electrochemical properties of surface modified Li1.05Ni0.35Co0.25Mn0.4O2 cathode material for lithium secondary battery. B Korean Chem Soc 29: 1695–1698. |
[149] |
Klett M, Gilbert JA, Pupek KZ, et al. (2017) Layered oxide, graphite and silicon-graphite electrodes for lithium-ion cells: Effect of electrolyte composition and cycling windows. J Electrochem Soc 164: A6095–A6102. doi: 10.1149/2.0131701jes
![]() |
[150] | Shim J, Striebel KA (2003) Characterization of high-power lithium-ion cells during constant current cycling: Part I. Cycle performance and electrochemical diagnostics. J Power Sources 122: 188–194. |
[151] |
Nakura K, Ariyoshi K, Ogaki F, et al. (2014) Characterization of lithium insertion electrodes: a method to measure area-specific impedance of single electrode. J Electrochem Soc 161: A841–A846. doi: 10.1149/2.090405jes
![]() |
[152] | Mauger A, Julien CM (2017) Critical review on lithium-ion batteries: are they safe? Sustainable? Ionics 23: 1933–1947. |
[153] |
Wang MS, Wang J, Zhang J, et al. (2015) Improving electrochemical performance of spherical LiMn2O4 cathode materials for lithium ion batteries by Al-F codoping and AlF3 surface coating. Ionics 21: 27–35. doi: 10.1007/s11581-014-1164-6
![]() |
[154] |
Tron A, Kang H, Kim J, et al. (2018) Electrochemical performance of AlF3-coated LiV3O8 for aqueous rechargeable lithium-ion batteries. J Electrochem Sci Te 9: 60–68. doi: 10.33961/JECST.2018.9.1.60
![]() |
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Name | ABA triblock copolymers | Hydrophobic molecular weight of the polymer (Da.) | fhydrophilic (Hydrophilic mass ratio) |
P2500 [a] | PMOXA500-PDMS2500-PMOXA500 [c] | 2500 | 28.57 % |
P4000 [b] | PMOXA1000-PDMS4000-PMOXA1000 [c] | 4000 | 33.33 % |
P5000 [b] | PMOXA1300-PDMS5000-PMOXA1300 [c] | 5000 | 34.21 % |
P8500 [a] | PMOXA1300-PDMS8500-PMOXA1300 [c] | 8500 | 23.40 % |
P8800 [a] | PMOXA2000-PDMS8800-PMOXA2000 [c] | 8800 | 31.25% |
[a] tri-block copolymers P2500, P8500 and P8800 are with hydroxyl end groups; [b] tri-block copolymers P4000 and P5000 are with methacrylate end groups which allow for a UV light induced polymerization; [c] In “PMOXAxxx-PDMSxxxx-PMOXAxxx”, the number after each block represents the molecular weight (Da.) of each block. |
Name | ABA triblock copolymers | Hydrophobic molecular weight of the polymer (Da.) | fhydrophilic (Hydrophilic mass ratio) |
P2500 [a] | PMOXA500-PDMS2500-PMOXA500 [c] | 2500 | 28.57 % |
P4000 [b] | PMOXA1000-PDMS4000-PMOXA1000 [c] | 4000 | 33.33 % |
P5000 [b] | PMOXA1300-PDMS5000-PMOXA1300 [c] | 5000 | 34.21 % |
P8500 [a] | PMOXA1300-PDMS8500-PMOXA1300 [c] | 8500 | 23.40 % |
P8800 [a] | PMOXA2000-PDMS8800-PMOXA2000 [c] | 8800 | 31.25% |
[a] tri-block copolymers P2500, P8500 and P8800 are with hydroxyl end groups; [b] tri-block copolymers P4000 and P5000 are with methacrylate end groups which allow for a UV light induced polymerization; [c] In “PMOXAxxx-PDMSxxxx-PMOXAxxx”, the number after each block represents the molecular weight (Da.) of each block. |