A polymer electrolyte based on poly(vinylidene fluoride-hexafluoropylene)/hydroxypropyl methyl cellulose blending for lithium-ion battery

A polymer electrolyte based on the blending of poly(vinylidene fluoride-hexafluoropylene) (PVDF-HFP) and hydroxypropyl methyl cellulose (HPMC) was prepared for the first time. The structure and performance of the gel polymer electrolyte were characterized and measured by X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, electrochemical impedance spectroscopy, linear sweep voltammetry, and by a charge/discharge test. The results show that the gel polymer electrolyte has the best performance when PVDF-HFP/HPMC ratio (w/w) is 4:1. At room temperature, the ionic conductivity can reach 0.38?×?10^?3 S cm^?1, the electrochemical stable window is up to 5.0 V (vs. Li/Li⁺), and the half cell of Li/GPE/LiMn₂O₄ shows high-discharge-specific capacity and good cycling performance.     

A free-standing and thermostable polymer/plastic crystal electrolyte for all-solid-state lithium batteries

All-solid-state lithium batteries using flexible solid electrolytes instead of combustible organic liquid electrolytes are the ultimate solution to address the safety problem of commercialized lithium ion batteries. In this study, a free-standing and thermostable polymer/plastic crystal composite electrolyte (PPCE) based on polymerized trimethylolpropane trimethacrylate (TMPTMA)-1, 6-hexanediol diacrylate (HDDA) matrix, and plastic crystal electrolyte was prepared for all-solid-state lithium batteries. The polymerized TMPTMA-HDDA-based matrix of a porous network structure coupled with plastic crystal electrolyte (PCE) in the pores reveals good compatibility. The as-synthesized PPCE possesses excellent flexible performance, thermostability, and high conductivity, showing that PPCE can reach 8.53 × 10^?4 S cm^?1 with 7.5 wt% monomers (PPCE-7.5%) at 25 °C under a stability electrochemical window above 5.2 V. The assembled lithium batteries Li|PPCE|LiFePO₄ exhibit high capacity and highly cycling stability at room temperature, indicating great potential of all-solid-state lithium batteries.     

Dinitrile compound containing ethylene oxide moiety with enhanced solubility of lithium salts as electrolyte solvent for high-voltage lithium-ion batteries

A dinitrile compound containing ethylene oxide moiety (4,7-dioxa-1,10-decanedinitrile, NEON) is synthesized as an electrolyte solvent for high-voltage lithium-ion batteries. The introduction of ethylene oxide moiety into the conventional aprotic aliphatic dinitrile compounds improves the solubility of lithium hexafluorophosphate (LiPF₆) used commercially in the lithium-ion battery industry. The electrochemical performances of the NEON-based electrolyte (0.8 M LiPF₆?+?0.2 M lithium oxalyldifluoroborate in NEON:EC:DEC, v:v:v?=?1:1:1) are evaluated in graphite/Li, LiCoO₂/Li, and LiCoO₂/graphite cells. Half-cell tests show that the electrolyte exhibits significantly improved compatibility with graphite by the addition of vinylene carbonate and lithium oxalyldifluoroborate and excellent cycling stability with a capacity retention of 97 % after 50 cycles at a cutoff voltage of 4.4 V in LiCoO₂/Li cell. A comparative experiment in LiCoO₂/graphite full cells shows that the electrolyte (NEON:EC:DEC, v:v:v?=?1:1:1) exhibits improved cycling stability at 4.4 V compared with the electrolyte without NEON (EC:DEC, v:v?=?1:1), demonstrating that NEON has a great potential as an electrolyte solvent for the high-voltage application in lithium-ion batteries.     

Synergistic film-forming effect of oligo(ethylene oxide)-functionalized trimethoxysilane and propylene carbonate electrolytes on graphite anode

Oligo(ethylene oxide)-functionalized trialkoxysilanes can be used as novel electrolytes for high-voltage cathode, such as LiCoO₂ (4.35 V) and Li_1.2Ni_0.2Mn_0.6O₂ (4.6 V); however, they are not well compatible with graphite anode. In this study, a synergistic solid electrolyte interphase (SEI) film-forming effect between [3-[2-(2-methoxyethoxy)ethoxy]propyl]-trimethoxysilane (TMSM2) and propylene carbonate (PC) on graphite electrode was investigated. Excellent SEI film-forming capability and cycling performance was observed in graphite/Li cells using the electrolyte of 1 M LiPF₆ in the binary solvent of TMSM2 and PC, with the PC content in the range of 10–30 vol.%. Meanwhile, the graphite/Li cells delivered higher specific capacity and better capacity retention in the electrolyte of 1 M LiPF₆ in TMSM2 and PC (TMSM2:PC = 9:1, by vol.), compared with those in the electrolyte of 1 M LiPF₆ in TMSM2 and EC (TMSM2:EC = 9:1, by vol.). The synergistic SEI film-forming properties of TMSM2 and PC on the surface of graphite anode was characterized by electrolyte solution structure analysis through Raman spectroscopy and surface analysis detected by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR) analysis.     

Effect of different compositions of ethylene carbonate and propylene carbonate containing iodide/triiodide redox electrolyte on the photovoltaic performance of DSSC

The effect of different compositions (in weight percent) of ethylene carbonate (EC) and propylene carbonate (PC) containing iodide/triiodide redox electrolyte on the photoelectrochemical performance of N719-sensitized nanocrystalline TiO₂ solar cell was studied. The cells consisted of 0.6 M 1-hexyl-2,3-dimethylimidazolium iodide, 0.1 M LiI, 0.05 M I₂ and 0.5 M 4-tert-butylpyridine in different compositions such as 1:1, 1:2, and 2:1 wt% of EC and PC. In 1:1 wt% of EC and PC containing redox electrolyte, short circuit photocurrent density (J _sc) increased and open circuit voltage (V _oc) decreased. But in 1:2 and 2:1 wt% of EC and PC containing redox electrolytes, V _oc increased and J _sc decreased but fill factor remained relatively constant. Dye-sensitized solar cells (DSSCs) prepared using these electrolytes give a short circuit photocurrent densities of 16.86, 12.71, and 12.09 mA/cm²; an open circuit voltages of 0.73, 0.78, and 0.79 V; fill factors of 0.63, 0.64, and 0.64; and an overall conversion efficiencies of 7.76, 6.34, and 6.13 % at an incident light of 100 mWcm^?2 for 1:1, 2:1, and 1:2 wt% of EC/PC containing redox electrolytes, respectively. The incident photon-to-current conversion efficiency was higher in the case of 1:1 wt% of EC and PC containing redox electrolyte than 1:2 and 2:1 wt% of EC and PC containing redox electrolyte. It revealed that 1:1 wt% of EC and PC containing iodide/triiodide redox electrolyte is an effective electrolyte system for the fabrication of long-term stable DSSC.     

Investigation on the storage performance of LiMn2O4 at elevated temperature with the mixture of electrolyte stabilizer

In order to investigate the effect of different electrolytes of LiPF₆-based and LiPF₆-based with the mixed additives of ethanolamine and heptamethyldisilazane on the storage performance of LiMn₂O₄, the commercial LiMn₂O₄ are added into these different electrolytes for storing deliberately at 60 °C in air for 4 h. The results show that the electrolyte with additives can prevent LiMn₂O₄ from being eroded by HF to a certain extent, and improve the storage performance of the material. The initial discharge capacities are 97.7 and 88.4 mAh g^?1 at 0.1 and 1?C, respectively, which are much higher than that 84.4 and 63.6 mAh?g^?1 of LiMn₂O₄ stored in the electrolyte without additives. Moreover, the former LiMn₂O₄ retains 89.1 % of its initial discharge capacity at 1?C after 150 cycles, while this is not up to 84 % for the latter.     

Hybrid solid electrolytes with excellent electrochemical properties and their applications in all-solid-state cells

Three types of inorganic electrolytes [Li₁₀GeP₂S₁₂ (LGPS), 75Li₂S·24P₂S₅·1P₂O₅ (LPOS), Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP)] with different particle sizes and electrochemical properties are selected as active fillers incorporated into poly(ethylene oxide) (PEO) matrix to fabricate hybrid solid electrolytes. The optimum composition of each filler is found in consideration of ionic conductivity. Their electrochemical characteristics are investigated. The optimal conductivities are 1.60 × 10^?5, 1.18 × 10^?5, and 2.12 × 10^?5 S cm^?1 at room temperature for PEO-1%LGPS, PEO-1%LPOS, and PEO-20%LAGP, respectively. The electrochemical stability windows of these hybrid solid electrolytes are all above 5 V (vs. Li⁺/Li). The results show that these fillers have positive effects on the ionic conductivity, lithium ion transference number, and electrochemical stability. The relationship between the type of filler and electrochemical properties has been investigated. All-solid-state cells LiFePO₄/Li are fabricated and present fascinating electrochemical performance with high capacity retention and good cycling stability. This work provides promising electrolytes prepared by a simple method.     

Improving the rate performance and stability of LiNi<Subscript>0.6</Subscript>Co<Subscript>0.2</Subscript>Mn<Subscript>0.2</Subscript>O<Subscript>2</Subscript> in high voltage lithium-ion battery by using fluoroethylene carbonate as electrolyte additive

Fluoroethylene carbonate (FEC) is investigated as the electrolyte additive to improve the electrochemical performance of high voltage LiNi_0.6Co_0.2Mn_0.2O₂ cathode material. Compared to LiNi_0.6Co_0.2Mn_0.2O₂/Li cells in blank electrolyte, the capacity retention of the cells with 5 wt% FEC in electrolytes after 80 times charge-discharge cycle between 3.0 and 4.5 V significantly improve from 82.0 to 89.7%. Besides, the capacity of LiNi_0.6Co_0.2Mn_0.2O₂/Li only obtains 12.6 mAh g^?1 at 5 C in base electrolyte, while the 5 wt% FEC in electrolyte can reach a high capacity of 71.3 mAh g^?1 at the same rate. The oxidative stability of the electrolyte with 5 wt% FEC is evaluated by linear sweep voltammetry and potentiostatic data. The LSV results show that the oxidation potential of the electrolytes with FEC is higher than 4.5 V vs. Li/Li⁺, while the oxidation peaks begin to appear near 4.3 V in the electrolyte without FEC. In addition, the effect of FEC on surface of LiNi_0.6Co_0.2Mn_0.2O₂ is elucidated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The analysis result indicates that FEC facilitates the formation of a more stable surface film on the LiNi_0.6Co_0.2Mn_0.2O₂ cathode. The electrochemical impedance spectroscopy (EIS) result evidences that the stable surface film could improve cathode electrolyte interfacial resistance. These results demonstrate that the FEC can apply as an additive for 4.5 V high voltage electrolyte system in LiNi_0.6Co_0.2Mn_0.2O₂/Li cells.     

Ethylene sulfate as film formation additive to improve the compatibility of graphite electrode for lithium-ion battery

Ethylene sulfate (DTD) is investigated as a novel film formation electrolyte additive for graphite anode material in lithium-ion battery. The CV results reveal that DTD is reduced prior to ethylene carbonate (EC) at the interface between graphite and electrolyte, while it cannot prevent the sustained reduction of propylene carbonate (PC) when the amount of DTD is lesser than 3 wt% in the PC-based electrolyte. XPS analyses demonstrate that the reduction products of DTD, Li₂SO₃, and ROSO₂Li are formed at the surface of graphite in the EC-based electrolyte, which is beneficial to lower the interfacial resistance as suggested by the EIS results. In addition, SEM images show a smoother and homogeneous surface film at the surface of graphite when DTD is incorporated into the electrolyte. Consequently, the Li/graphite half cells cycled in EC-based electrolyte containing DTD exhibit higher specific capacity and improved cycling capability than that without DTD.     

A piperidinium-based ionic liquid electrolyte to enhance the electrochemical properties of LiFePO<Subscript>4</Subscript> battery

A piperidinium-based ionic liquid, N-methylpiperidinium-N-acetate bis(trifluoromethylsulfonyl)imide ([MMEPip][TFSI]), was synthesized and used as an additive to the electrolyte of LiFePO₄ battery. The electrochemical performance of the electrolytes based on different contents of [MMEPip][TFSI] has been investigated. It was found that the [MMEPip][TFSI] significantly improved the high-rate performance and cyclability of the LiFePO₄ cells. In the optimized electrolyte with 3 wt% [MMEPip][TFSI], 70 % capacity can be retained with an increase in rate to 3.5 C, which was 8 % higher than that of electrolyte without [MMEPip][TFSI]. For the Li/LiFePO₄ half-cells, after 100 cycles at 0.1 C, the discharge capacity retention was 78 % in the electrolyte without ionic liquid. However, in the electrolyte with 3 wt% [MMEPip][TFSI], it displayed a high capacity retention of 91 %. The good electrochemical performances indicated that the [MMEPip][TFSI] additive would positively enhance the electrochemical performance of LiFePO₄ battery.     

A comparative study on the effects of salt and filler on transport and structural properties of organic–inorganic hybrid electrolytes

Organic–inorganic hybrid electrolytes based on the reaction of tri-block copolymer poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether), poly(ethylene glycol diglycidyl ether, and (3-glycidyloxypropyl)trimethoxysilane doped with LiClO₄ and SiO₂ nanoparticles were synthesized by a sol–gel process. The structural and dynamic properties of the materials thus obtained were systematically investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, alternate current impedance, and ¹³C solid-state NMR measurements. A maximum ionic conductivity of 3.2?×?10^?5 S cm^?1 was obtained at 30 °C for the solid hybrid electrolyte with a [O]/[Li] ratio of 16 and 7 wt% of SiO₂ nanoparticles. A Vogel–Tamman–Fulcher-like temperature dependence of ionic conductivity was observed for the hybrid electrolytes, implying that the diffusion of charge carriers was assisted by the segmental motions of the polymer chains.     

Polyethylene-supported poly(methyl methacrylate<Emphasis Type="Italic">-co-</Emphasis>butyl acrylate)-based novel gel polymer electrolyte for lithium ion battery

A new copolymer, poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)), was synthesized by emulsion polymerization with different mass ratio of methyl methacrylate (MMA) and butyl acrylate (BA). The membranes were prepared by phase inversion and corresponding gel polymer electrolytes (GPEs) were obtained by immersing the membrane into a liquid electrolyte. In this design, the hard monomer MMA provided the copolymer with good electrolyte uptake, while the soft monomer BA provided the GPE with strong adhesion between the anode and cathode of lithium ion battery. The properties of the resulting product were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectra, scanning electron spectroscopy, linear sweep voltammetry, thermogravimetric analysis, cyclic voltammetry, electrochemical impedance spectroscopy and charge/discharge test. The results show that the obtained GPE based on P(MMA-co-BA) with the mass ratios of MMA and BA = 6:1 exhibits good conductivity (as high as 1.2 × 10^?3 S cm^?1) at room temperature and high electrochemical stability (up to 4.9 V vs. Li/Li⁺). With the application of the polyethylene (PE)-supported GPE in Li/Li(Li_0.13Ni_0.30Mn_0.57)O₂ battery, the battery presents good cyclic stability (maintaining 95.4 % of its initial discharge capacity after 50 cycles) at room temperature.     

PVC–PMMA composite electrospun membranes as polymer electrolytes for polymer lithium-ion batteries

Composite nanofibrous membranes based on poly (vinyl chloride) (PVC)?Cpoly (methyl methacrylate) (PMMA) were prepared by electrospinning and then they were soaked in liquid electrolyte to form polymer electrolytes (PEs). The introduction of PMMA into the PVC matrix enhanced the compatibility between the polymer matrix and the liquid electrolyte. The composite nanofibrous membranes prepared by electrospinning involved a fully interconnected pore structure facilitating high electrolyte uptake and easy transport of ions. The ion conductivity of the PEs increased with the increase in PMMA content in the blend and the ion conductivity of the polymer electrolyte based on PVC?CPMMA (5:5, w/w) blend was 1.36?×?10^?3 S cm^?1 at 25?°C. The polymer electrolyte based on PVC?CPMMA (5:5, w/w) blend presented good electrochemical stability up to 5.0?V (vs. Li/Li⁺) and good interfacial stability with the lithium electrode. The promising results showed that nanofibrous PEs based on PVC?CPMMA were of great potential application in polymer lithium-ion batteries.     

Polymer electrolytes based on vinyl ethers with various EO chain length and their polymer electrolytes cross-linked by electron beam irradiation

Polymer electrolytes based on vinyl ethers with various ethyleneoxy (EO) chain length (poly-1a (m?=?3), poly-1b (m?=?6), poly-1c (m?=?10), and poly-1d (m?=?23.5)) with lithium bis(trifluoromethanesulfonimide) (LiTFSI) were prepared, and effect of pendant EO chain length in the polymers on electrochemical and thermal properties was investigated. Glass transition temperature (T _g) of all polymer electrolytes increased linearly with an increase in salt concentrations. Ionic conductivities of the polymer electrolytes increased with an increase in the pendant EO chain length of the polymers at the constant [Li]/[O] ratio, but in the polymer electrolyte of the poly-1d (m?=?23.5) with the longest pendant EO chain length, ionic conductivity decreased in the low temperature range of ?20 to 10 °C due to the crystallization of the pendant EO chain. The highest ionic conductivity, 1.23?×?10^?4 S/cm at 30 °C, was obtained in the polymer electrolyte of the poly-1c (m?=?10) with pendant EO chain length of 10 at the [Li]/[O] ratio of 1/20. It was found that the cross-linking of the polymer electrolyte, composed of poly-1c (m?=?10) with LiTFSI at the [Li]/[O] ratio of 1/28, by electron beam (EB) irradiation may improve the mechanical property without affecting ionic conductivity, thermal property, and oxidation stability. Polymer electrolytes based on poly-1a (m?=?3), poly-1b (m?=?6), poly-1c (m?=?10), and poly-1d (m?=?23.5) and cross-linked polymer electrolytes were electrochemically stable until 4 V and thermally stable around 300 °C.     

NH<Subscript>4</Subscript>NO<Subscript>3</Subscript> as charge carrier contributor in glycerolized potato starch-methyl cellulose blend-based polymer electrolyte and the application in electrochemical double-layer capacitor

Potato starch (PS)-methyl cellulose (MC) blend solid biopolymer electrolytes infused with ammonium nitrate (NH₄NO₃) and glycerol as plasticizer are made via the solution cast technique. Fourier transform infrared (FTIR) spectroscopy indicates that NH₄NO₃ has interacted with the polymer blend host. The addition of 40 wt% glycerol in the highest conducting plasticizer free electrolyte has improved the conductivity to the order of ～10^?3 S cm^?1. The thermal stability of the electrolytes is identified by thermogravimetric analysis (TGA). Result from X-ray diffraction (XRD) analysis shows that the electrolyte with maximum conductivity value has the lowest degree of crystallinity. Differential scanning calorimetry (DSC) analysis reveals that the highest conducting plasticized electrolyte possesses the lowest glass transition temperature (T _g) of ?27.5 °C. Conductivity trend is further verified by dielectric analysis. Transference numbers of ion (t _ion) and electron (t _e) for the highest conducting electrolyte are identified to be 0.98 and 0.02, respectively, confirming that ions are the dominant charge carriers. Linear sweep voltammetry (LSV) evaluates that the potential window for the electrolyte is 1.88 V. The internal resistance of the electrochemical double-layer capacitor (EDLC) is between 29 and 64 Ω. From the charged-discharged measurement, the value of C _s is 31 F g^?1. The EDLC is stable over 1000 cycles.     

Preparation and performance of the polyethylene-supported polyvinylidene fluoride/cellulose acetate butyrate/nano-SiO<Subscript>2</Subscript> particles blended gel polymer electrolyte

The preparation of polyethylene-supported poly(vinylidene fluoride)/cellulose acetate butyrate/nano-SiO₂ particle (PVDF-CAB-SiO₂/PE) blended gel polymer electrolytes (GPEs) is reported here. The electrolyte uptake, mechanical properties, thermal stability, and electrochemical performance of these electrolytes are characterized to evaluate their potential application in lithium-ion batteries (LIBs). The results indicate that the particle size of SiO₂ can be adjusted by the tetraethyl orthosilicate (TEOS) concentration and affects the physicochemical properties of the membrane. By doping 5 wt.% SiO₂ (500 nm) into the PVdF-CAB blended polymer, the porosity of the membrane increases from 40 to 42.3 %, the mechanical strength from 117.3 to 138.7 MPa, the electrolyte uptake from 149 to 195 %, the oxidation decomposition potential from 4.7 to 5.2 V, and the ionic conductivity of the corresponding GPE is improved from 1.16 to 2.98 mS cm^?1 at ambient temperature. The PVDF-CAB-SiO₂/PE-based GPE and the two electrodes are suitably compatible, and the thermal stability is higher than that of the polyethylene (PE) membrane. The LIBs with the as-prepared GPE also exhibit enhanced discharge capacity and cycle stability, indicating the promising application of these GPEs in LIBs.     

Electrical properties of proton conducting solid biopolymer electrolytes based on starch–chitosan blend

Two systems (salted and plasticized) of starch–chitosan blend-based electrolytes incorporated with ammonium chloride (NH₄Cl) are prepared via solution cast technique. The incorporation of 25 wt% NH₄Cl has maximized the room temperature conductivity of the electrolyte to (6.47?±?1.30)?×?10^?7 S cm^?1. Conductivity is enhanced to (5.11?±?1.60)?×?10^?4 S cm^?1 on addition of 35 wt% glycerol. The temperature dependence of conductivity for all electrolytes is Arrhenian, and the value of activation energy (E _a ) decreases with increasing conductivity. Conductivity is found to be influenced by the number density (n) and mobility (μ) of ions. The complexation between the electrolytes components is proven by Fourier transform infrared analysis. The relaxation time (t _r ) for selected electrolytes is found to decrease with increasing conductivity and temperature. Conduction mechanism for the highest conducting electrolyte in salted and plasticized systems is determined by employing Jonscher’s universal power law.     

Stability of Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/Al in ionic liquid BMI.BF<Subscript>4</Subscript>/γ-butyrolactone electrolytes for use in electrolytic capacitors

The stability of aluminium oxide has been investigated in mixtures of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF₄) and γ-butyrolactone (GBL) for application as the impregnation electrolyte of aluminium electrolytic capacitors. Ionic conductivity measurements of BMI.BF₄/GBL electrolytes at different temperatures were performed, as well as electrochemical impedance spectroscopy and cyclic voltammetry experiments. The results show that the highest ionic conductivity value of 40 mS cm^?1 (70 °C) is achieved in electrolyte x _BMI.BF4 = 0.2. The total capacitance values, associated with the dielectric oxides, vary between 1 and 8 μF cm^?2 for all studied electrolytes after 30 days of immersion. The polarization resistance and total capacitance of the electrolyte/Al₂O₃/Al system decrease slightly with immersion time, showing the stability of Al₂O₃/Al in ionic liquid BMI.BF₄/GBL electrolytes.     

Vibrational,electrical, and ion transport properties of PVA-LiClO<Subscript>4</Subscript>-sulfolane electrolyte with high cationic conductivity

Novel solid polymer electrolytes, poly(vinylalcohol)-lithium perchlorate (PVA-LiClO₄) and PVA-LiClO₄-sulfolane are prepared by solvent casting method. The experimental results show that sulfolane addition enhances the ionic conductivity of PVA-LiClO₄ complex by three orders. The maximum ionic conductivity of 1.14 ± 0.20 × 10^?2 S cm^?1 is achieved for 10 mol% sulfolane-added electrolyte at ambient temperature. Polymer-salt-plasticizer interactions are analyzed through attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Lithium ion transference number is found by AC impedance spectroscopy combined with DC potentiostatic measurements. The results confirm that sulfolane improves the Li⁺ transference number of PVA-LiClO₄ complex to 0.77 from 0.40. The electrochemical stability window of electrolytes is determined by cyclic voltammetry (CV). The broad electrochemical stability window of 5.45 V vs. lithium is obtained for maximum conducting electrolyte. All-solid-state cell is fabricated using maximum conducting electrolyte, and electrochemical impedance study is carried out. It reveals that electrolyte interfacial resistance with Li electrode is very low. The use of PVA-LiClO₄-sulfolane as a viable electrolyte material for high-voltage lithium ion batteries is ensured.     

Exploring low temperature Li+ ion conducting plastic battery electrolyte

We report blend-based plastic polymer electrolyte (i.e., polyethylene oxide (PEO)–polydimethyl siloxane (PDMS)–lithium hexafluorophosphate (LiPF₆)) with substantial improvement in DC conductivity at ambient and subambient temperatures when compared with literature reports. Conductivity variation with salt concentration, investigated within ±30 °C range, indicates an optimum conductivity of 5.6?×?10^?5 S cm^?1 at 30 °C for Ö/Li ~10 with a further lowering by one order at 0 °C and it remains unaltered at ?10 °C. Enhanced conductivity in this blend electrolyte, though lower than two copolymer counterparts, is attributed to very low glass transition temperatures of the host polymers. X-ray diffraction (XRD) and scanning electron microscopy (SEM) suggest an effective blending between the two polymers with an effective interaction between the Li salt and the blend polymer matrix. Raman spectroscopy results indicated that cation (Li⁺) coordination occurs at the C=Ö site in PEO out of the two electron-rich sites (i.e., CÖ and Si–Ö–Si) in the PEO–PDMS blend. The blend electrolytes are predominantly ionic (t _ion ~97 %).