Incorporation of Ionic Conductive Polymers into Sulfide Electrolyte-Based Solid-State Batteries to Enhance Electrochemical Stability and Cycle Life

Sulfide-based inorganic solid electrolytes are promising materials for high-performance safe solid-state batteries.The high ion conductivity,mechanical characteristics,and good processability of sulfide-based inorganic solid electrolytes are desirable properties for realizing high-performance safe solid-state batteries by replacing conventional liquid electrolytes.However,the low chemical and electrochemical stability of sulfide-based inorganic solid electrolytes hinder the commercialization of sulfide-based safe solid-state batteries.Particularly,the instability of sulfide-based inorganic solid electrolytes is intensified in the cathode,comprising various materials.In this study,carbonate-based ionic conductive polymers are introduced to the cathode to protect cathode materials and suppress the reactivity of sulfide electrolytes.Several instruments,including electrochemical spectroscopy,X-ray photoelectron spectroscopy,and scanning electron microscopy,confirm the chemical and electrochemical stability of the polymer electrolytes in contact with sulfide-based inorganic solid electrolytes.Sulfide-based solid-state cells show stable electrochemical performance over 100 cycles when the ionic conductive polymers were applied to the cathode.

A Modification of LiMn2O4 by Ionic Conductive Agent and Electronic Conductive Agent Coating

Carbon was used as electronic conductive agent, and metasilicic acid lithium (Li2SiO3) as ionic conductive agent, the two factors were investigated cooperatively. We evaluated their effect by using spherical spinel LiMn2O4 which prepared ourselves as cathode material. Then Li2SiO3/carbon surface coating on LiMn2O4 (LMO/C/LSO) which Li2SiO3 inside and carbon/Li2SiO3 coated LiMn2O4 (LMO/LSO/C) were prepared, All of materials were characterized by X-ray diffraction (XRD) and electrochemical test;spherical LiMn2O4 was characterized by scanning electron microscopy (SEM);and coated materials were characterized by transmission electron microscopy (TEM). While uncoated spinel LiMn2O4 maintained 72% of capacity in 60 cycles by the rate of 0.2C, and LMO/LSO/C showed the best electrochemical performance, 89% of the initial capacity remained after 75 cycles at 0.2C. Furthermore, the rate performance of LMO/LSO/C also improved obviously, about 30 mAh·g-1 of capacity attained at the rate of 5C, higher than LMO/C/LSO and bare LiMn2O4.

A Stretchable Ionic Conductive Elastomer for High-Areal-Capacity Lithium-Metal Batteries

Developing high-areal-capacity and dendrite-free lithium(Li)anodes is of significant importance for the practical applications of the Li-metal secondary batteries.Herein,an effective strategy to stabilize the high-arealcapacity Li electrodeposition by modifying the Li metal with a stretchable ionic conductive elastomer(ICE)is demonstrated.The ICE layer prepared via an instant photocuring process shows a promising Li^(+)-ion conductivity at room temperature.When being used in Li-metal batteries,the thin ICE coating(~0.27μm)acts as both a stretchable constraint to minimize the Li loss and a protective layer to facilitate the uniform flux of Li ions.With this ICE-modifying strategy,the reversibility and cyclability of the Li anodes under high-areal-capacity condition in carbonate electrolyte are significantly improved,leading to a stable Li stripping/plating for 500 h at an ultrahigh areal capacity of 20 mAh cm^(-2)in commercial carbonate electrolyte.When coupled with industry-level thick LiFePO;electrodes(20.0 mg cm^(-2)),the cells with ICE-Li anodes show significantly enhanced rate and cycling capability.

Enabling high-performance all-solid-state lithium batteries with high ionic conductive sulfide-based composite solid electrolyte and ex-situ artificial SEI film

All-solid-state lithium batteries(ASSLBs) employing sulfide electrolyte and lithium(Li) anode have received increasing attention due to the intrinsic safety and high energy density.However,the thick electrolyte layer and lithium dendrites formed at the electrolyte/Li anode interface hinder the realization of high-performance ASSLBs.Herein,a novel membrane consisting of Li_(6)PS_(5) Cl(LPSCl),poly(ethylene oxide)(PEO) and Li-salt(LiTFSI) was prepared as sulfide-based composite solid electrolyte(LPSCl-PEO3-LiTFSI)(LPSCl:PEO=97:3 wt/wt;EO:Li=8:1 mol/mol),which delivers high ionic conductivity(1.1 × 10^(-3) S cm^(-1)) and wide electrochemical window(4.9 V vs.Li^(+)/Li) at 25 ℃.In addition,an ex-situ artificial solid electrolyte interphase(SEI) film enriched with LiF and Li3 N was designed as a protective layer on Li anode(Li(SEI)) to suppress the growth of lithium dendrites.Benefiting from the synergy of sulfide-based composite solid electrolyte and ex-situ artificial SEI,cells of S-CNTs/LPSCI-PEO3-LiTFSI/Li(SEI) and Al_(2)O_(3)@LiNi_(0.5)Co_(0.3)Mn_(0.2)O_(2)/LPSCl-PEO3-LiTFSI/Li(SEI) are assembled and both exhibit high initial discharge capacity of 1221.1 mAh g^(-1)(135.8 mAh g^(-1)) and enhanced cycling stability with 81.6% capacity retention over 200 cycles at 0.05 C(89.2% over 100 cycles at 0.1 C).This work provides a new insight into the synergy of composite solid electrolyte and artificial SEI for achieving high-performance ASSLBs.

A healable, mechanically robust and ultrastretchable ionic conductive elastomer for durably wearable sensor

The ionic conductive elastomers show great promise in multifunctional wearable electronics,but they currently suffer from liquid leakage/evaporation or mechanical compliance.Developing ionic conductive elastomers integrating non-volatility,mechanical robustness,superior ionic conductivity,and ultra-stretchability remains urgent and challenging.Here,we developed a healable,robust,and conductive elastomer via impregnating free ionic liquids(ILs)into the ILs-multigrafted poly(urethane-urea)(PUU)elastomer networks.A crucial strategy in the molecular design is that imidazolium cations are largely introduced by double-modification of PUU and centipede-like structures are obtained,which can lock the impregnated ILs through strong ionic interactions.In this system,the PUU matrix contributes outstanding mechanical properties,while the hydrogen bonds and ionic interactions endow the elastomer with self-healing ability,conductivity,as well as non-volatility and transparency.The fabricated ionic conductive elastomers show good conductivity(3.8×10^(-6) S·cm^(-1)),high mechanical properties,including tensile stress(4.64 MPa),elongation(1470%),and excellent healing ability(repairing efficiency of 90%after healing at room temperature for 12 h).Significantly,the conductive elastomers have excellent antifatigue properties,and demonstrate a highly reproducible response after 1000 uninterrupted extension-release cycles.This work provides a promising strategy to prepare ionic conductive elastomers with excellent mechanical properties and stable sensing capacity,and further promote the development of mechanically adaptable intelligent sensors.

Ionic conductive hydrogels toughened by latex particles for strain sensors

Conductive hydrogels have attracted tremendous attention due to their excellent softness and stretchability as wearable strain sensing devices.However,most of hydrogel-based strain sensors suffered from poor self-recoverability and fatigue resistance,resulting in significant decrease of strain sensitivity after recycling.Here,a soft and flexible wearable strain sensor is prepared by using an ionic conductive hydrogel with latex particles as physical cross-linking centers.The dynamic physical cross-linking structure can effectively dissipate energy through disruption and reconstruction of molecular segments,thereby imparting excellent stretchability,self-recoverability and fatigue resistance.In addition,the hydrogel exhibits excellent strain-sensitive resistance changes,which enables it to be assembled as a wearable sensor to monitor human motions.As a result,the hydrogel strain sensor can provide precise feedback for a wide range of human activities,including large-scale joint bending and tiny phonating.Therefore,the tough ionic conductive hydrogel would be widely applied in electronic skin,medical monitoring and artificial intelligence.

Electrically Detaching Behavior and Mechanism of Ionic Conductive Adhesives

Design of rapidly detachable adhesives with high initial bonding strength is of great significance but it is full of great challenge. Here, we report the fast electrically detaching behavior (100% detaching efficiency in just 1 min under dozens of DC voltage) and high initial bonding strength (>12 MPa) of epoxy-based ionic conductive adhesives (ICAs). The epoxy-based ICAs are fabricated by introducing polyethylene glycol dimethyl ether (PEGDE) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]OTF) into epoxy. The combination of PEGDE and [EMIM]OTF enables the free ions to migrate directively in electric field, and the anchoring of PEG chains onto epoxy chains ensures the long-term reliability of ICAs. The investigation on the electrically detaching mechanism suggests that the enrichment and following rapid interfacial electrochemical reactions of [EMIM]OTF lead to formation of metal hydroxide (Me(OH)n) nanoparticles at the bonding interfaces, thus the strong interactions containing interlocked forces, van de Waals’ forces and hydrogen bonding interactions between ICAs and bonding substrates are destroyed. This work provides a promising direction for detachable adhesives with both high initial bonding strength and high detaching efficiency in short time.

Preparation and Characterization of lonic Conductive Eutectogels Based on Polyacrylamide Copolymers with Long Hydrophobic Chain

With the blooming development of electronic technology,the use of electron conductive gel or ionic conductive gel in preparing flexible electronic devices is drawing more and more attention.Deep eutectic solvents are excellent substitutes for ionic liquids because of their good biocompatibility,low cost,and easy preparation,except for good conductivity.In this work,we synthesized a reactive quaternary ammonium monomer(3-acrylamidopropyl)octadecyldimethyl ammonium bromide with a hydrophobic chain of 18 carbons via the quaternization of 1-bromooctadecane and N-dimethylaminopropyl acrylamide at first,then we mixed quaternary ammonium with choline chloride,acrylic acid and glycerol to obtain a hydrophobic deep eutectic solvent,and initialized polymerization in UV light of 365 nm to obtain the ionic conductive eutectogel based on polyacrylamide copolymer with long hydrophobic chain.The obtained eutectogel exibits good stretchability(1200%),Young's modulus(0.185 MPa),toughness(4.2 MJ/m^(3)),conductivity(0.315 S/m).The eutectogel also shows desireable moisture resistance with the maximum water absorption of 11.7 wt%after one week at 25℃ and 60% humidity,while the water absorption of eutectogel without hydrophobic long chains is 24.0 wt%.The introduction of long-chain hydrophobic groups not only improves the mechanical strength of the gels,but also significantly improves moisture resistance of the eutectogel.This work provides a simpler and more effective method for the preparation of ionic conductive eutectogels,which can further provide a reference for the applications of ionic conductive eutectogels in the field of flexible electronic devices.

High ionic conductive protection layer on Zn metal anode for enhanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries(ZIBs)has been regarded as a promising energy storage system for large-scale application due to the advantages of low cost and high safety.However,the growth of Zn dendrite,hydrogen evolution and passivation issues induce the poor electrochemical performance of ZIBs.Herein,a Na_(3)Zr_(2)Si_(2)PO_(12)(NZSP)protection layer with high ionic conductivity of 2.94 m S/cm on Zn metal anode was fabricated by drop casting approach.The protection layer prevents Zn dendrites formation,hydrogen evolution as well as passivation,and facilitates a fast Zn~(2+)transport.As a result,the symmetric cells based on NZSP-coated Zn show a stable cycling over 1360 h at 0.5 m A/cm^(2)with 0.5 m Ah/cm^(2) and 1000 h even at a high current density of 5 m A/cm^(2) with 2 m Ah/cm^(2).Moreover,the full cells combined with V_(2)O_(5)-based cathode displays high capacities and high rate capability.This work offers a facile and effective approach to stabilizing Zn metal anode for enhanced ZIBs.

Intrinsically ionic conductive nanofibrils for ultra-thin bio-memristor with low operating voltage

Memristors integrated with low operating voltage,good stability,and environmental benignity play an important role in data storage and logical circuit technology,but their fabrication still faces challenges.This study reports an ultra-thin bio-memristor based on pristine environmentfriendly silk nanofibrils(SNFs).The intrinsic ionic conductivity,combined with high dielectric performance and nanoscale thickness,lowers the operation voltage down to0.1-0.2 V,and enables stable switching and retention time over 180 times and 10^(5)s,respectively.Furthermore,the SNFbased memristor device in a crossbar array achieves stable memristive performance,and thus realizes the functions of memorizing image and logic operation.By carrying out variable-temperature electrical experiments and Kelvin probe force microscopy,the space charge-limited conduction mechanism is revealed.Integrating with low operating voltage,good stability,and ultra-thin thickness makes the SNF-based memristors excellent candidates in bioelectronics.

A highly ionic conductive succinonitrile-based composite solid electrolyte for lithium metal batteries

Solid-state Li metal batteries with solid electrolytes have built a potential way to solve the safety and low energy density problems of current commercial Li-ion batteries with liquid electrolyte.As a key component of solid-state Li metal batteries,solid electrolytes require high ionic conductivities and good mechanical properties.We have designed a composite solid electrolyte(CSE)consisting of poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)-Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZTO)-succinonitrile(SN)and Li bis(trifluoromethylsulphonyl)imide(LiTFSI).The PVDF-HFP-based porous matrix made by electrospinning ensures good mechanical properties of the electrolyte membrane,and the large proportion of SN filling material makes the electrolyte membrane have an ionic conductivity of 1.11 mS·cm^(–1)without the addition of liquid electrolyte.The symmetric battery assembled with CSE can be cycled stably for more than 600 h,and the LiFePO4|CSE|Li full battery can also be cycled stably for more than 200 cycles.In addition to Li metal batteries,Li-O_(2)and Li-CO_(2)batteries that use CSE as electrolytes also have good performances,reflecting the universality of CSE.CSE does not only guarantee good mechanical properties but also obtain a high ionic conductivity.This design provides a new idea for the commercial application of polymer-based solid batteries.

Organic fast ion-conductor with ordered Li-ion conductive nano-pathways and high ionic conductivity for electrochemical energy storage

Solid electrolyte(SE)is the most crucial factor to fabricate safe and high-performance all-solid-state lithium-ion batteries.However,the most commonly reported SE,including solid polymer electrolyte(SPE)and inorganic oxides and sulfides,suffer problems of low ionic conductivity at room temperature for SPE and large interfacial impedance with electrodes for inorganic electrolytes.Here we for the first time demonstrate a novel ionic plastic crystal lithium salt solid electrolyte(OLiSSE)fast ion-conductor dilithium(1,3-diethyl-4,5-dicarboxylate)imidazole bromide with ordered Li-ion conductive nanopathways and an exceptional ionic conductivity of 4.4×10^(−3)Scm^(−1)at 30℃.The prepared OLiSSE exhibits apparent characters of typical ionic plastic crystals in the temperature range of−20 to 70℃,and shows remarkable thermal stability and electrochemical stability below 150℃ and 4.7 V,respectively.No lithium dendrite or short circuit behavior is detected for the Li|OLiSSE|Li cell after the galvanostatic charge-discharge test for 500 h.The fabricated Li|OLiSSE|LiFePO_(4) all-solid-state cell without using any separator and liquid plasticizer directly delivers an initial discharge capacity of 151.4 mAh g^(−1) at the discharge rate of 0.1 C,and shows excellent charge-discharge cycle stability,implying large potential application in the next generation of safe and flexible all-solid-state lithium batteries.

High-capacity,high-rate,and dendrite-free lithium metal anodes based on a 3D mixed electronic-ionic conductive and lithiophilic scaffold

Lithium metal anode possesses a high theoretical capacity and the lowest redox potential,while the severe growth of Li dendrite prevents its practical application.Herein,we prepared a structure of Li_(3)P nanosheets and Ni nanoparticles decorated on Ni foam(NF)as a three-dimensional(3 D)scaffold for dendrite-free Li metal anodes(Li-Li_(3)P/Ni@Ni foam anodes,shortened as L-LPNNF)using a facile melting method.The LiP nanosheets exhibit excellent Li-ion conductivity as well as superior lithiophilicity,and the 3 D nickel scaffold provides sufficient electron conductivity and ensures structure stability.Therefore,symmetric cells assembled by L-LPNNF possess lowered voltage hysteresis and improved long cycle stability(a voltage hysteresis of 104.2 mV after 500 cycles at a high current density of 20 mA cm^(-2) with a high capacity of 10 mA h cm^(-2)),compared with the cells assembled with Li foil or Li-NF anodes.Furthermore,the full cells with paired L-LPNNF anodes and commercial LiFePOcathodes suggest a specific capacity of 124.6 mA h gand capacity retention of 90.8%after 180 cycles with the Coulombic efficiency(CE)of~100%at a current rate of 1 C.This work provides a potentially scalable option for preparing a mixed electronic-ionic conductive and lithiophilic scaffold for dendrite-free Li anodes at high current densities.

Bacterial Cellulose/Zwitterionic Dual-network Porous Gel Polymer Electrolytes with High Ionic Conductivity

Bacterial cellulose(BC)was innovatively combined with zwitterionic copolymer acrylamide and sulfobetaine methacrylic acid ester[P(AM-co-SBMA)]to build a dual-network porous structure gel polymer electrolytes(GPEs)with high ionic conductivity.The dual network structure BC/P(AM-co-SBMA)gels were formed by a simple one-step polymerization method.The results show that ionic conductivity of BC/P(AM-co-SBMA)GPEs at the room temperature are 3.2×10^(-2) S/cm@1 M H_(2)SO_(4),4.5×10^(-2) S/cm@4 M KOH,and 3.6×10^(-2) S/cm@1 M NaCl,respectively.Using active carbon(AC)as the electrodes,BC/P(AM-co-SBMA)GPEs as both separator and electrolyte matrix,and 4 M KOH as the electrolyte,a symmetric solid supercapacitors(SSC)(AC-GPE-KOH)was assembled and testified.The specific capacitance of AC electrode is 173 F/g and remains 95.0%of the initial value after 5000 cycles and 86.2%after 10,000 cycles.

Improvement of ionic conductivity of solid polymer electrolyte based on Cu-Al bimetallic metal-organic framework fabricated through molecular grafting

A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of the PEO-based electrolytes.Experimental and molecular dynamics simulation results indicated that the electrolyte with 10 wt.%CAB(PL-CAB-10%)exhibits high ionic conductivity(8.42×10~(-4)S/cm at 60℃),high Li+transference number(0.46),wide electrochemical window(4.91 V),good thermal stability,and outstanding mechanical properties.Furthermore,PL-CAB-10%exhibits excellent cycle stability in both Li-Li symmetric battery and Li/PL-CAB-10%/LiFePO4 asymmetric battery setups.These enhanced performances are primarily attributable to the introduction of the versatile CAB.The abundant metal sites in CAB can react with TFSI~-and PEO through Lewis acid-base interactions,promoting LiTFSI dissociation and improving ionic conductivity.Additionally,regular pores in CAB provide uniformly distributed sites for cation plating during cycling.

Alternative Strategy for Development of Dielectric Calcium Copper Titanate‑Based Electrolytes for Low‑Temperature Solid Oxide Fuel Cells

The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of SOFCs.This has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of SOFCs.In this context,for the first time,a dielectric material,CaCu_(3)Ti_(4)O_(12)(CCTO)is designed for LT-SOFCs electrolyte application in this study.Both individual CCTO and its heterostructure materials with a p-type Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ)(NCAL)semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550℃.The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm^(-2) and an open-circuit voltage(OCV)of 0.95 V at 550℃,while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm^(-2) along with a higher OCV over 1.0 V,which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting risk.It is found that these promising outcomes are due to the interplay of the dielectric material,its structure,and overall properties that led to improve electrochemical mechanism in CCTO–NCAL.Furthermore,density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–NCAL.Our study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.

Ionic Conduction and Fuel Cell Performance of Ba0.98Ce0.8Tm0.2O3-α Ceramic

The perovskite-type oxide solid solution Ba0.98Ce0.8Tm0.2O3-α was prepared by high temperature solid-state reaction and its single phase character was confirmed by X-ray diffraction. The conduction property of the sample was investigated by alternating current impedance spectroscopy and gas concentration cell methods under different gases atmospheres in the temperature range of 500-900 ℃. The performance of the hydrogen-air fuel cell using the sample as solid electrolyte was measured. In wet hydrogen, the sample is a pure protonic conductor with the protonic transport number of 1 in the range of 500-600 ℃, a mixed conductor of proton and electron with the protonic transport number of 0.945-0.933 above 600 ℃. In wet air, the sample is a mixed conductor of proton, oxide ion, and electronic hole. The protonic transport numbers are 0.010-0.021, and the oxide ionic transport numbers are 0.471-0.382. In hydrogen-air fuel cell, the sample is a mixed conductor of proton, oxide ion and electron, the ionic transport numbers are 0.942 0.885. The fuel cell using Ba0.98Ce0.8Tm0.2O3-α as solid electrolyte can work stably. At 900 ℃, the maximum power output density is 110,2 mW/cm2, which is higher than that of our previous cell using Ba0.98Ce0.8Tm0.2O3-α （x〈≤1, RE=Y, Eu, Ho） as solid electrolyte.

Oxygen ionic conductivity of a composite electrolyte SDC-LSGM prepared via glycine-nitrate process

Ce0.8Sm0.2O1.9-δ-La0.9Sr0.1Ga0.8Mg0.2O3-δ（SDC-LSGM）is prepared by the glycine-nitrate process（GNP）.SDC-LSGM composite electrolyte samples with different weight ratios are prepared by the co-combustion method so as to obtain homogeneous nano-sized precursor powders. The X-ray diffraction （XRD） and the scan electron microscope （SEM） are used to investigate the phases and microstructures. The measurements and analyses of oxygen ionic conductivity of SDC-LSGM are carried out through the four-terminal direct current （DC） method and the electrochemical impendence spectroscopy, respectively. The optimum weight ratio of SDC-LSGM is 8∶2, of which the ionic conductivity is 0.113 S/cm at 800℃ and the conductivity activation energy is 0.620 eV. The impendence spectra shows that the grain boundary resistance becomes the main barrier for the ionic conductivity of electrolyte at lower temperatures. The appropriate introduction of LSGM to the electrolyte SDC can not only decrease the electronic conductivity but also improve the conditions of the grain and grain boundary, which is advantageous to cause an increase in oxygen ionic conductivity.

Synthesis and Ionic Conduction of Cation-deficient Apatite La9.33-2x/3MxSi6O26 Doped with Mg, Ca, Sr

Apatite-type lanthanum silicate with special conduction mechanism via interstitial oxygen has attracted considerable interest in recent years. In this work, pure powder of La9.33 2x/3MxSi6O26 （M=Mg, Ca, Sr） is prepared by the sol-gel method with sintering at 1000℃. The powder is characterized by X-ray diffraction （XRD） and scanning electron micrograph （SEM）. The apatite can be obtained at relatively low temperature as compared to the conventional solid-state reaction method. The measurements of conductivity of a series of doped samples La9.33-2x/3MxSi6O26 （M=Ca, Mg, Sr） indicate that the type of dopant and the amount have a significant effect on the conductivity. The greatest decrease in conductivity is observed for Mg doping, following the Ca and the Sr doped apatites. The effect is ultimately attributed to the amount of oxygen interstitials, which is affected by the crystal lattice distortion arising from cation vacancies.

Synthesis and characterization of mixing soft-segmented waterborne polyurethane polymer electrolyte with room temperature ionic liquid

Composite polymer electrolytes based on mixing soft-segment waterborne polyurethane （WPU） and 1-butyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl]imide （BMImTFSI） have been prepared and characterized. The addition of BMImTFSI results in an increase of the ionic conductivity. At high BMImTFSI concentration （BMImTFSI/WPU = 3 in weight ratio）, the ionic conductivity reaches 4.27 × 10^-3 S/cm at 30 ℃. These composite polymer electrolytes exhibit good thermal and electrochemical stability, which are high enough to be applied in lithium batteries.