Sandwich-type composited solid polymer electrolytes to strengthen the interfacial ionic transportation and bulk conductivity for all-solid-state lithium batteries from room temperature to 120℃

The insurmountable charge transfer impedance at the Li metal/solid polymer electrolytes(SPEs)interface at room temperature as well as the ascending risk of short circuits at the operating temperature higher than the melting point,dominantly limits their applications in solid-state batteries(SSBs).Although the inorganic filler such as CeO_(2)nanoparticle content of composite solid polymer electrolytes(CSPEs)can significantly reduce the enormous charge transfer impedance at the Li metal/SPEs interface,we found that the required content of CeO_(2)nanoparticles in SPEs varies for achieving a decent interfacial charge transfer impedance and the bulk ionic conductivity in CSPEs.In this regard,a sandwich-type composited solid polymer electrolyte with a 10%CeO_(2)CSPEs interlayer sandwiched between two 50%CeO_(2)CSPEs thin layers(sandwiched CSPEs)is constructed to simultaneously achieve low charge transfer impedance and superior ionic conductivity at 30℃.The sandwiched CSPEs allow for stable cycling of Li plating and stripping for 1000 h with 129 mV polarized voltage at 0.1 mA cm^(-2)and 30℃.In addition,the LiFePO_(4)/Sandwiched CSPEs/Li cell also exhibits exceptional cycle performance at 30℃and even elevated120℃without short circuits.Constructing multi-layered CSPEs with optimized contents of the inorganic fillers can be an efficient method for developing all solid-state PEO-based batteries with high performance at a wide range of temperatures.

Advancements and Challenges in Organic–Inorganic Composite Solid Electrolytes for All‑Solid‑State Lithium Batteries

To address the limitations of contemporary lithium-ion batteries,particularly their low energy density and safety concerns,all-solid-state lithium batteries equipped with solid-state electrolytes have been identified as an up-and-coming alternative.Among the various SEs,organic–inorganic composite solid electrolytes(OICSEs)that combine the advantages of both polymer and inorganic materials demonstrate promising potential for large-scale applications.However,OICSEs still face many challenges in practical applications,such as low ionic conductivity and poor interfacial stability,which severely limit their applications.This review provides a comprehensive overview of recent research advancements in OICSEs.Specifically,the influence of inorganic fillers on the main functional parameters of OICSEs,including ionic conductivity,Li+transfer number,mechanical strength,electrochemical stability,electronic conductivity,and thermal stability are systematically discussed.The lithium-ion conduction mechanism of OICSE is thoroughly analyzed and concluded from the microscopic perspective.Besides,the classic inorganic filler types,including both inert and active fillers,are categorized with special emphasis on the relationship between inorganic filler structure design and the electrochemical performance of OICSEs.Finally,the advanced characterization techniques relevant to OICSEs are summarized,and the challenges and perspectives on the future development of OICSEs are also highlighted for constructing superior ASSLBs.

12.6μm-Thick Asymmetric Composite Electrolyte with Superior Interfacial Stability for Solid-State Lithium-Metal Batteries

Solid-state lithium metal batteries(SSLMBs)show great promise in terms of high-energy-density and high-safety performance.However,there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes,and to minimize the electrolyte thickness to achieve highenergy-density of SSLMBs.Herein,we develop an ultrathin(12.6μm)asymmetric composite solid-state electrolyte with ultralight areal density(1.69 mg cm^(−2))for SSLMBs.The electrolyte combining a garnet(LLZO)layer and a metal organic framework(MOF)layer,which are fabricated on both sides of the polyethylene(PE)separator separately by tape casting.The PE separator endows the electrolyte with flexibility and excellent mechanical properties.The LLZO layer on the cathode side ensures high chemical stability at high voltage.The MOF layer on the anode side achieves a stable electric field and uniform Li flux,thus promoting uniform Li^(+)deposition.Thanks to the well-designed structure,the Li symmetric battery exhibits an ultralong cycle life(5000 h),and high-voltage SSLMBs achieve stable cycle performance.The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg^(−1)/773.1 Wh L^(−1).This simple operation allows for large-scale preparation,and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs.

Construction of a High‑Performance Composite Solid Electrolyte Through In‑Situ Polymerization within a Self‑Supported Porous Garnet Framework

Composite solid electrolytes(CSEs)have emerged as promising candidates for safe and high-energy–density solid-state lithium metal batteries(SSLMBs).However,concurrently achieving exceptional ionic conductivity and interface compatibility between the electrolyte and electrode presents a significant challenge in the development of high-performance CSEs for SSLMBs.To overcome these challenges,we present a method involving the in-situ polymerization of a monomer within a self-supported porous Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZT)to produce the CSE.The synergy of the continuous conductive LLZT network,well-organized polymer,and their interface can enhance the ionic conductivity of the CSE at room temperature.Furthermore,the in-situ polymerization process can also con-struct the integration and compatibility of the solid electrolyte–solid electrode interface.The synthesized CSE exhibited a high ionic conductivity of 1.117 mS cm^(-1),a significant lithium transference number of 0.627,and exhibited electrochemical stability up to 5.06 V vs.Li/Li+at 30℃.Moreover,the Li|CSE|LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cell delivered a discharge capacity of 105.1 mAh g^(-1) after 400 cycles at 0.5 C and 30℃,corresponding to a capacity retention of 61%.This methodology could be extended to a variety of ceramic,polymer electrolytes,or battery systems,thereby offering a viable strategy to improve the electrochemical properties of CSEs for high-energy–density SSLMBs.

PDOL-Based Solid Electrolyte Toward Practical Application:Opportunities and Challenges

Polymer solid-state lithium batteries(SSLB)are regarded as a promising energy storage technology to meet growing demand due to their high energy density and safety.Ion conductivity,interface stability and battery assembly process are still the main challenges to hurdle the commercialization of SSLB.As the main component of SSLB,poly(1,3-dioxolane)(PDOL)-based solid polymer electrolytes polymerized in-situ are becoming a promising candidate solid elec-trolyte,for their high ion conductivity at room temperature,good battery elec-trochemical performances,and simple assembly process.This review analyzes opportunities and challenges of PDOL electrolytes toward practical application for polymer SSLB.The focuses include exploring the polymerization mechanism of DOL,the performance of PDOL composite electrolytes,and the application of PDOL.Furthermore,we provide a perspective on future research directions that need to be emphasized for commercialization of PDOL-based electrolytes in SSLB.The exploration of these schemes facilitates a comprehensive and profound understanding of PDOL-based polymer electrolyte and provides new research ideas to boost them toward practical application in solid-state batteries.

Revealing the specific role of sulfide and nano-alumina in composite solid-state electrolytes for performance-reinforced ether-nitrile copolymers

Composite solid-state electrolytes represent a critical pathway that balances the interface compatibility and lithium-ion conductivity in all-solid-state batteries.The quest for stable and highly ion-conductive combinations between polymers and fillers is vital,but blind attempts are often made due to a lack of understanding of the mechanisms involved in the interaction between polymers and fillers.Herein,we employ in-situ polymerization to prepare a polymer based on an ether-nitrile copolymer with high cathode stability as the foundation and discuss the performance enhancement mechanisms of argyrodite and nano-alumina.With 1%content of sulfide interacting with the polymer at the two-phase interface,the local enhancement of lithium-ion migration capability can be achieved,avoiding the reduction in capacity due to the low ion conductivity of the passivation layer during cycling.The capacity retention after 50cycles at 0.5 C increases from 83.5%to 94.4%.Nano-alumina,through anchoring the anions and interface inhibition functions,eventually poses an initial discharge capacity of 136.8 m A h g^(-1)at 0.5 C and extends the cycling time to 1000 h without short-circuiting in lithium metal batteries.Through the combined action of dual fillers on the composite solid-state electrolyte,promising insights are provided for future material design.

A"Concentrated lonogel-in-Ceramic"Silanization Composite Electrolyte with Superior Bulk Conductivity and Low Interfacial Resistance for Quasi-Solid-State Li Metal Batteries

The ideal composite electrolyte for the pursued safe and high-energy-density lithium metal batteries(LMBs)is expected to demonstrate peculiarity of superior bulk conductivity,low interfacial resistances,and good compatibility against both Li-metal anode and high-voltage cathode.There is no composite electrolyte to synchronously meet all these requirements yet,and the battery performance is inhibited by the absence of effective electrolyte design.Here we report a unique"concentrated ionogel-in-ceramic"silanization composite electrolyte(SCE)and validate an electrolyte design strategy based on the coupling of high-content silane-conditioning garnet and concentrated ionogel that builds well-percolated Li+transport pathways and tackles the interface issues to respond all the aforementioned requirements.It is revealed that the silane conditioning enables the uniform dispersion of garnet nanoparticles at high content(70 wt%)and forms mixed-lithiophobic-conductive LiF-Li3N solid electrolyte interphase.Notably,the yielding SCE delivers an ultrahigh ionic conductivity of 1.76 X 10^(-3)S cm^(-1)at 25℃,an extremely low Li-metal/electrolyte interfacial area-specific resistance of 13Ωcm^(2),and a distinctly excellent long-term 1200 cycling without any capacity decay in 4.3 V Li‖LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)quasi-solid-state LMB.This composite electrolyte design strategy can be extended to other quasi-/solid-state LMBs.

A Tri-Salt Composite Electrolyte with Temperature Switch Function for Intelligently Temperature-Controlled Lithium Batteries

The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles.The emerging of intelligent control in kinds of devices brings new requirements for battery systems.The high-energy lithium batteries are expected to respond or react under different environmental conditions.In this work,a tri-salt composite electrolyte is designed with a temperature switch function for intelligently temperature-controlled lithium batteries.Specifically,the halide Li_(3)YBr_(6)together with LiTFSI and LiNO_(3)works as active fillers in a low-melting-point polymer matrix(polyethyleneglycol dimethyl ether(PEGDME)and polyethylene oxide(PEO)),which is further filled into the pre-lithiated alumina fiber skeleton.Above 60°C,the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface,effectively minimizing the interfacial resistance and leading to high discharge capacity in the cell.The electrolyte is changed into a solid state below 30°C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid interface.Therefore,by simply adjusting the temperature,the cell can be turned“ON”or“OFF”intentionally.This novel function of the composite electrolyte has enlightening significance in developing intelligently temperature-controlled lithium batteries.

Synergistic coupling among Mg_(2)B_(2)O_(5),polycarbonate and N,Ndimethylformamide enhances the electrochemical performance of PVDF-HFP-based solid electrolyte

Polymer solid electrolytes(SPEs)based on the[solvate-Li+]complex structure have promising prospects in lithium metal batteries(LMBs)due to their unique ion transport mechanism.However,the solvation structure may compromise the mechanical performance and safety,hindering practical application of SPEs.In this work,a composite solid electrolyte(CSE)is designed through the organic-inorganic syner-gistic interaction among N,N-dimethylformamide(DMF),polycarbonate(PC),and Mg_(2)B_(2)O_(5) in poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP).Flame-retardant Mg_(2)B_(2)O_(5) nanowires provide non-flammability to the prepared CSEs,and the addition of PC improves the dispersion of Mg_(2)B_(2)O_(5) nanowires.Simultaneously,the organic-inorganic synergistic action of PC plasticizer and Mg_(2)B_(2)O_(5) nanowires pro-motes the dissociation degree of LiTFSI and reduces the crystallinity of PVDF-HFP,enabling rapid Li ion transport.Additionally,Raman spectroscopy and DFT calculations confirm the coordination between Mg atoms in Mg_(2)B_(2)O_(5) and N atoms in DMF,which exhibits Lewis base-like behavior attacking adjacent C-F and C-H bonds in PVDF-HFP while inducing dehydrofluorination of PVDF-HFP.Based on the syner-gistic coupling of Mg_(2)B_(2)O_(5),PC,and DMF in the PVDF-HFP matrix,the prepared CSE exhibits superior ion conductivity(9.78×10^(-4) s cm^(-1)).The assembled Li symmetric cells cycle stably for 3900 h at a current density of 0.1 mA cm^(-2) without short circuit.The LFP||Li cells assembled with PDL-Mg_(2)B_(2)O_(5)/PC CSEs show excellent rate capability and cycling performance,with a capacity retention of 83.3%after 1000 cycles at 0.5 C.This work provides a novel approach for the practical application of organic-inorganic Synergistic CSEs in LMBs.

Tailoring Practically Accessible Polymer/Inorganic Composite Electrolytes for All-Solid-State Lithium Metal Batteries:A Review

Solid-state electrolytes(SSEs)are widely considered the essential components for upcoming rechargeable lithium-ion batteries owing to the potential for great safety and energy density.Among them,polymer solid-state electrolytes(PSEs)are competitive candidates for replacing commercial liquid electrolytes due to their flexibility,shape versatility and easy machinability.Despite the rapid development of PSEs,their practical application still faces obstacles including poor ionic conductivity,narrow electrochemical stable window and inferior mechanical strength.Polymer/inorganic composite electrolytes(PIEs)formed by adding ceramic fillers in PSEs merge the benefits of PSEs and inorganic solid-state electrolytes(ISEs),exhibiting appreciable comprehensive properties due to the abundant interfaces with unique characteristics.Some PIEs are highly compatible with high-voltage cathode and lithium metal anode,which offer desirable access to obtaining lithium metal batteries with high energy density.This review elucidates the current issues and recent advances in PIEs.The performance of PIEs was remarkably influenced by the characteristics of the fillers including type,content,morphology,arrangement and surface groups.We focus on the molecular interaction between different components in the composite environment for designing high-performance PIEs.Finally,the obstacles and opportunities for creating high-performance PIEs are outlined.This review aims to provide some theoretical guidance and direction for the development of PIEs.

Status and prospect of garnet/polymer solid composite electrolytes for all-solid-state lithium batteries

Solid polymer electrolytes(SPEs), such as polyethylene oxide(PEO), are characteristic of good flexibility and excellent processability, but they suffer from low ionic conductivity and small Li+transference number at ambient temperature. Inorganic solid electrolytes(ISEs), garnet-type Li7La3Zr2O12 and its derivatives(LLZO-based) in particular, possess high ionic conductivity at room temperature, wide electrochemical stability window, large Li+transference number as well as good stability against Li metal anode.Nevertheless, lithium dendrites growth, interfacial contact issue and brittle nature of LLZO-based ceramic electrolytes prevent their practical applications. In response to these shortcomings, LLZO-based/polymer solid composite electrolytes(SCEs), taking complementary advantages of two kinds of electrolytes, and thus simultaneously improving the electrode wettability, ionic conductivity and mechanical strength, have been made to develop high-performance SCEs in recent years. Herein, the intrinsic properties and research progress of LLZO-based/polymer SCEs, including LLZO-based/PEO SCEs(LLZO-based/PEO SCEs with uniform dispersion of LLZO-based fillers and LLZO-based/PEO layered SCEs) and LLZO-based/novel polymers SCEs, are summarized. Besides, comprehensive updates on their applications in solid-state batteries are also presented. Finally, challenges and perspectives of LLZO-based/polymer SCEs for advanced allsolid-state lithium batteries(ASSLBs) are suggested. This review paper aims to provide systematic research progress of LLZO-based/polymer SCEs, to allow for more efficient and target-oriented research on improving LLZO-based/polymer SCEs.

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.

Quasi-Solid-State Ion-Conducting Arrays Composite Electrolytes with Fast Ion Transport Vertical-Aligned Interfaces for All-Weather Practical Lithium-Metal Batteries

The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs.However,different ion transport capacity between solvent and polymer will cause local nonuniform Li+distribution,leading to severe dendrite growth.In addition,the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes.Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs.Here,a strategy by introducing ion-conducting arrays(ICA)is created by vertical-aligned montmorillonite into GPE.Rapid ion transport on the ICA was demonstrated by 6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction,combined with computer simulations to visualize the transport process.Compared with conventional randomly dispersed fillers,ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures.Therefore,GPE/ICA exhibits high room-temperature ionic conductivity(1.08 mS cm^(−1))and long-term stable Li deposition/stripping cycles(>1000 h).As a final proof,Li||GPE/ICA||LiFePO_(4) cells exhibit excellent cycle performance at wide temperature range(from 0 to 60°C),which shows a promising path toward all-weather practical solid-state batteries.

Anion-immobilized solid composite electrolytes based on metal-organic frameworks and superacid ZrO_(2) fillers for high-performance all solid-state lithium metal batteries

Anion-immobilized solid composite electrolytes(SCEs)are important to restrain the propagation of lithium dendrites for all solid-state lithium metal batteries(ASSLMBs).Herein,a novel SCEs based on metal-organic frameworks(MOFs,UiO-66-NH_(2))and superacid ZrO_(2)(S-ZrO_(2))fillers are proposed,and the samples were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),thermo-gravimetric analyzer(TGA)and some other electrochemical measurements.The-NH_(2) groups of UiO-66-NH_(2) combines with F atoms of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)chains by hydrogen bonds,leading to a high electrochemical stability window of 5 V.Owing to the incorporation of UiO-66-NH_(2) and S-ZrO_(2) in PVDF-HFP polymer,the open metal sites of MOFs and acid surfaces of S-ZrO_(2) can immobilize anions by strong Lewis acid-base interaction,which enhances the effect of immobilization anions,achieving a high Li-ion transference number(t_(+))of 0.72,and acquiring a high ionic conductivity of 1.05×10^(-4) S·cm^(-1) at 60℃.The symmetrical Li/Li cells with the anion-immobilized SCEs may steadily operate for over 600 h at 0.05 mA·cm^(-2) without the shortcircuit occurring.Besides,the solid composite Li/LiFePO_(4)(LFP)cell with the anion-immobilized SCEs shows a superior discharge specific capacity of 158 mAh·g^(-1) at 0.2 C.The results illustrate that the anion-immobilized SCEs are one of the most promising choices to optimize the performances of ASSLMBs.

LiF and LiNO_(3) as synergistic additives for PEO-PVDF/LLZTO-based composite electrolyte towards high-voltage lithium batteries with dualinterfaces stability

Solid electrolytes with desirable properties such as high ionic conductivity,wide electrochemical stable window,and suitable mechanical strength,and stable electrode-electrolyte interfaces on both cathode and anode side are essential for high-voltage all-solid-state lithium batteries(ASSLBs)to achieve excellent cycle stability.In this work,a novel strategy of using LiF and LiNO_(3) as synergistic additives to boost the performance of PEO-PVDF/LLZTO-based composite solid electrolytes(CSEs)is developed,which also promotes the assembled high-voltage ASSLBs with dual-interfaces stability characteristic.Specifically,LiF as an inactive additive can increase the electrochemical stability of the CSE under high cut-off voltage,and improve the high-voltage compatibility between cathode and CSE,thus leading to a stable cathode/CSE interface.LiNO_(3) as an active additive can lead to an enhanced ionic conductivity of CSE due to the increased free-mobile Li+and ensure a stable CSE/Li interface by forming stable solid electrolyte interphase(SEI)on Li anode surface.Benefiting from the improved performance of CSE and stable dualinterfaces,the assembled NCM622/9[PEO_(15)-LiTFSI]-PVDF-15 LLZTO-2 LiF-3 LiNO_(3)/Li cell delivers a high rate capacity of 102.1 mAh g^(-1) at 1.0 C and a high capacity retention of 77.4%after 200 cycles at 0.5 C,which are much higher than those of the ASSLB assembled with additive-free CSE,with only 60.0 mAh g^(-1) and 52.0%,respectively.Furthermore,novel cycle test modes of resting for 5 h at different charge states after every 5 cycles are designed to investigate the high-voltage compatibility between cathode and CSE,and the results suggest that LiF additive can actually improve the high-voltage compatibility of cathode and CSE.All the obtained results confirm that the strategy of using synergistic additives in CSE is an effective way to achieve high-voltage ASSLBs with dual-interfaces stability.

Research progress in electrospinning engineering for all-solid-state electrolytes of lithium metal batteries

Owing to safety issue and low energy density of liquid lithium-ion batteries(LIBs),all-solid-state lithium metal batteries(ASLMBs)with unique all-solid-state electrolytes(SEs)have attracted wide attentions.This arises mainly from the advantages of the SEs in the suppression of lithium dendrite growth,long cycle life,and broad working temperature range,showing huge potential applications in electronic devices,electric vehicles,smart grids,and biomedical devices.However,SEs suffer from low lithiumion conductivity and low mechanical integrity,slowing down the development of practical ASLMBs.Nanostructure engineering is of great efficiency in tuning the structure and composition of the SEs with improved lithium-ion conductivity and mechanical integrity.Among various available technologies for nanostructure engineering,electrospinning is a promising technique because of its simple operation,cost-effectiveness,and efficient integration with different components.In this review,we will first give a simple description of the electrospinning process.Then,the use of electrospinning technique in the synthesis of various SEs is summarized,for example,organic nanofibrous matrix,organic/inorganic nanofibrous matrix,and inorganic nanofibrous matrix combined with other components.The current development of the advanced architectures of SEs through electrospinning technology is also presented to provide references and ideas for designing high-performance ASLMBs.Finally,an outlook and further challenges in the preparation of advanced SEs for ASLMBs through electrospinning engineering are given.

Practical development and challenges of garnet-structured Li_(7)La_(3)Zr_(2)O_(12) electrolytes for all-solid-state lithium-ion batteries:A review

All-solid-state Li-ion batteries(ASSLIBs)have been widely studied to achieve Li-ion batteries(LIBs)with high safety and energy density.Recent reviews and experimental papers have focused on methods that improve the ionic conductivity,stabilize the electrochemical performance,and enhance the electrolyte/electrode interfacial compatibility of several solid-state electrolytes(SSEs),including oxides,sulfides,composite and gel electrolytes,and so on.Garnet-structured Li_(7)La_(3)Zr_(2)O_(12)(LLZO)is highly regarded an SSE with excellent application potential.However,this type of electrolyte also possesses a number of disadvantages,such as low ionic conductivity,unstable cubic phase,and poor interfacial compatibility with anodes/cathodes.The benefits of LLZO have urged many researchers to explore effective solutions to overcome its inherent limitations.Herein,we review recent developments on garnet-structured LLZO and provide comprehensive insights to guide the development of garnet-structured LLZO-type electrolytes.We not only systematically and comprehensively discuss the preparation,element doping,structure,stability,and interfacial improvement of LLZOs but also provide future perspectives for these materials.This review expands the current understanding on advanced solid garnet electrolytes and provides meaningful guidance for the commercialization of ASSLIBs.

The critical role of inorganic nanofillers in solid polymer composite electrolyte for Li+transportation

Compared with commercial lithium batteries with liquid electrolytes,all-solidstate lithium batteries(ASSLBs)possess the advantages of higher safety,better electrochemical stability,higher energy density,and longer cycle life;therefore,ASSLBs have been identified as promising candidates for next-generation safe and stable high-energy-storage devices.The design and fabrication of solid-state electrolytes(SSEs)are vital for the future commercialization of ASSLBs.Among various SSEs,solid polymer composite electrolytes(SPCEs)consisting of inorganic nanofillers and polymer matrix have shown great application prospects in the practice of ASSLBs.The incorporation of inorganic nanofillers into the polymer matrix has been considered as a crucial method to achieve high ionic conductivity for SPCE.In this review,the mechanisms of Li+transport variation caused by incorporating inorganic nanofillers into the polymer matrix are discussed in detail.On the basis of the recent progress,the respective contributions of polymer chains,passive ceramic nanofillers,and active ceramic nanofillers in affecting the Li+transport process of SPCE are reviewed systematically.The inherent relationship between the morphological characteristics of inorganic nanofillers and the ionic conductivity of the resultant SPCE is discussed.Finally,the challenges and future perspectives for developing high-performance SPCE are put forward.This review aims to provide possible strategies for the further improvement of ionic conductivity in inorganic nanoscale filler-reinforced SPCE and highlight their inspiration for future research directions.

MOF-derived multifunctional filler reinforced polymer electrolyte for solid-state lithium batteries

Solid-state lithium batteries(SSLBs) have attracted great interest from researchers due to their inherent high energy density and high safety performance.In order to develop SSLBs,the following two key problems should be solved:(1) Improving the lithium ion conductivity of solid electrolyte at room temperature;and(2) improving the interface between the electrode and the electrolyte.Herein,we propose a new multifunctional filler for reinforcing polymer electrolytes.The composite solid electrolytes(CSEs)mainly contain a MOF-derived Co-doped hollow porous carbon nanocage,which absorbs Li~+ containing ionic liquid(Li-ILs@HPCN),polyethylene oxide(PEO) and lithium bis(trifluoromethanesulfonyl)imide.By optimizing the composition of the CSEs,the CSEs membrane with high ionic conductivity(1.91×10^(-4) S cm^(-1) at 30℃),wide electrochemical stability(5.2 V) and high mobility of lithium ion(0.5) was obtained.Even at a current density of 0.2 mA cm^(-2),the PILH electrolyte possesses excellent interfacial stability against Li metal in Li symmetrical batteries exceeds 1600 h.Finally,the SSLBs(LFP/PILH/Li) showed excellent cycle stability,and the capacity was maintained at 152.9 and140.0 mA h g^(-1) after 150 cycles at a current density of 0.2 C and 0.5 C.This work proposes a completely new strategy for building high-performance SSLBs.

The Critical Role of Fillers in Composite Polymer Electrolytes for Lithium Battery

With excellent energy densities and highly safe performance,solidstate lithium batteries(SSLBs)have been hailed as promising energy storage devices.Solid-state electrolyte is the core component of SSLBs and plays an essential role in the safety and electrochemical performance of the cells.Composite polymer electrolytes(CPEs)are considered as one of the most promising candidates among all solid-state electrolytes due to their excellent comprehensive performance.In this review,we briefly introduce the components of CPEs,such as the polymer matrix and the species of fillers,as well as the integration of fillers in the polymers.In particular,we focus on the two major obstacles that affect the development of CPEs:the low ionic conductivity of the electrolyte and high interfacial impedance.We provide insight into the factors influencing ionic conductivity,in terms of macroscopic and microscopic aspects,including the aggregated structure of the polymer,ion migration rate and carrier concentration.In addition,we also discuss the electrode-electrolyte interface and summarize methods for improving this interface.It is expected that this review will provide feasible solutions for modifying CPEs through further understanding of the ion conduction mechanism in CPEs and for improving the compatibility of the electrode-electrolyte interface.