Amino-modified UiO-66-NH_(2) reinforced polyurethane based polymer electrolytes for high-voltage solid-state lithium metal batteries

Solid-state polymer electrolytes(SPEs)are candidate schemes for meeting the safety and energy density needs of advanced lithium-based battery because of their improved mechanical and electrochemical stability compared to traditional liquid electrolytes.However,low ionic conductivity and side reactions occurring in traditional high-voltage lithium metal batteries(LMBs)hinder their practical applications.Here,amino-modified metal-organic frameworks(UiO-66-NH_(2))with abundant defects as multifunctional fillers in the polyurethane based SPEs achieve the collaborative promotion of the mechanical strength and room temperature ionic conductivity.The surface modified amino groups serve as anchoring points for oxygen atoms of polymer chains,forming a firmly hydrogen-bond interface with polycarbonate-based polyurethane frameworks.The rich interfaces between UiO-66-NH_(2) and polymers dramatically decrease the crystallization of polymer chains and reduce ion transport impedance,which markedly boosted the ionic conductivity to 2.1×10^(−4) S·cm^(−1) with a high Li+transference numbers of 0.71.As a result,LiFePO4∣SPEs∣Li cells exhibit prominent cyclability for 700 cycles under 0.5 C with 96.5%capacity retention.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)∣SPEs∣Li cells deliver excellent long-term lifespan for 260 cycles with a high capacity retention of 91.9%and high average Coulombic efficiency(98.5%)under ambient conditions.This simple and effective hybrid SPE design strategy sheds a milestone significance light for high-voltage Li-metal batteries.

Synergetic Control of Li^(+)Transport Ability and Solid Electrolyte Interphase by Boron-Rich Hexagonal Skeleton Structured All-Solid-State Polymer Electrolyte

High Li^(+)transference number electrolytes have long been understood to provide attractive candidates for realizing uniform deposition of Li^(+).However,such electrolytes with immobilized anions would result in incomplete solid electrolyte interphase(SEI)formation on the Li anode because it suffers from the absence of appropriate inorganic components entirely derived from anions decomposition.Herein,a boron-rich hexagonal polymer structured all-solid-state polymer electrolyte(BSPE+10%LiBOB)with regulated intermolecular interaction is proposed to trade off a high Li^(+)transference number against stable SEI properties.The Li^(+)transference number of the as-prepared electrolyte is increased from 0.23 to 0.83 owing to the boron-rich cross-linker(BC)addition.More intriguingly,for the first time,the experiments combined with theoretical calculation results reveal that BOB^(-)anions have stronger interaction with B atoms in polymer chain than TFSI^(-),which significantly induce the TFSI^(-)decomposition and consequently increase the amount of LiF and Li3N in the SEI layer.Eventually,a LiFePO_(4)|BSPE+10%LiBOBlLi cell retains 96.7%after 400 cycles while the cell without BC-resisted electrolyte only retains 40.8%.BSPE+10%LiBOB also facilitates stable electrochemical cycling of solid-state Li-S cells.This study blazes a new trail in controlling the Li^(+)transport ability and SEI properties,synergistically.

Interpenetrating network-reinforced gel polymer electrolyte for ultra-stable lithium−iodine batteries

Li-I_(2) batteries have attracted much interest due to their high capacity,exceptional rate performance,and low cost.Even so,the problems of unstable Li anode/electrolyte interface and severe polyiodide shuttle in Li-I_(2) batteries need to be tackled.Herein,the interfacial reactions on the Li anode and I_(2) cathode have been effectively optimized by employing a well-designed gel polymer electrolyte strengthened by cross-linked Ti-O/Si-O(GPETS).The interpenetrating network-reinforced GPETS with high ionic conductivity(1.88×10^(-3)S cm^(-1)at 25℃)and high mechanical strength endows uniform Li deposition/stripping over 1800 h(at 1.0mA cm^(-2),with a plating capacity of 3.0mAh cm^(-2)).Moreover,the GPETS abundant in surface hydroxyls is capable of capturing soluble polyiodides at the interface and accelerating their conversion kinetics,thus synergistically mitigating the shuttle effect.Benefiting from these properties,the use of GPETS results in a high capacity of 207 mAh g^(-1)(1 C)and an ultra-low fading rate of 0.013%per cycle over 2000 cycles(5 C).The current study provides new insights into advanced electrolytes for Li-I_(2) batteries.

In-situ polymerized PEO-based solid electrolytes contribute better Li metal batteries:Challenges,strategies,and perspectives

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.

Enhancing interfacial stability in solid-state lithium batteries with polymer/garnet solid electrolyte and composite cathode framework

The solid-state lithium battery is considered as an ideal next-generation energy storage device owing to its high safety,high energy density and low cost.However,the poor ionic conductivity of solid electrolyte and low interfacial stability has hindered the application of solid-state lithium battery.Here,a flexible polymer/garnet solid electrolyte is prepared with poly(ethylene oxide),poly(vinylidene fluoride),Li6.75La3 Zr1.75Ta0.25O12,lithium bis(trifluoromethanesulfonyl)imide and oxalate,which exhibits an ionic conductivity of 2.0 ×10^(-4) S cm^(-1) at 55℃,improved mechanical property,wide electrochemical window(4.8 V vs.Li/Li+),enhanced thermal stabilities.Tiny acidic OX was introduced to inhibit the alkalinity reactions between Li6.75La3 Zr1.75Ta0.25O12 and poly(vinylidene fluoride).In order to improve the interfacial stability between cathode and electrolyte,an Al2 O3@LiNi0.5Co0.2Mn0.3O2 based composite cathode framework is also fabricated with poly(ethylene oxide) polymer and lithium salt as additives.The solid-state lithium battery assembled with polymer/garnet solid electrolyte and composite cathode framework demonstrates a high initial discharge capacity of 150.6 mAh g^(-1) and good capacity retention of 86.7% after 80 cycles at 0.2 C and 55℃,which provides a promising choice for achieving the stable electrode/electrolyte interfacial contact in solid-state lithium batteries.

Mechanistically Novel Frontal-Inspired In Situ Photopolymerization:An Efficient Electrode|Electrolyte Interface Engineering Method for High Energy Lithium Metal Polymer Batteries

The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention has been given to the eco-friendly and rapid ultraviolet(UV)-induced in situ photopolymerization process to prepare solid-state polymer electrolytes.In this respect,an innovative method is proposed here to overcome the challenges of UV-induced photopolymerization(UV-curing)in the zones where UV-light cannot penetrate,especially in LMPBs where thick electrodes are used.The proposed frontal-inspired photopolymerization(FIPP)process is a diverged frontal-based technique that uses two classes(dual)of initiators to improve the slow reaction kinetics of allyl-based monomers/oligomers by at least 50%compared with the conventional UV-curing process.The possible reaction mechanism occurring in FIPP is demonstrated using density functional theory calculations and spectroscopic investigations.Indeed,the initiation mechanism identified for the FIPP relies on a photochemical pathway rather than an exothermic propagating front forms during the UV-irradiation step as the case with the classical frontal photopolymerization technique.Besides,the FIPP-based in situ cell fabrication using dual initiators is advantageous over both the sandwich cell assembly and conventional in situ photopolymerization in overcoming the limitations of mass transport and active material utilization in high energy and high power LMPBs that use thick electrodes.Furthermore,the LMPB cells fabricated using the in situ-FIPP process with high mass loading LiFePO_(4)electrodes(5.2 mg cm^(-2))demonstrate higher rate capability,and a 50%increase in specific capacity against a sandwich cell encouraging the use of this innovative process in large-scale solid-state battery production.

Improving ionic conductivity of polymer-based solid electrolytes for lithium metal batteries

Because of its superior safety and excellent processability,solid polymer electrolytes(SPEs)have attracted widespread attention.In lithium based batteries,SPEs have great prospects in replacing leaky and flammable liquid electrolytes.However,the low ionic conductivity of SPEs cannot meet the requirements of high energy density systems,which is also an important obstacle to its practical application.In this respect,escalating charge carriers(i.e.Li^(+))and Li^(+)transport paths are two major aspects of improving the ionic conductivity of SPEs.This article reviews recent advances from the two perspectives,and the underlying mechanism of these proposed strategies is discussed,including increasing the Li^(+)number and optimizing the Li^(+)transport paths through increasing the types and shortening the distance of Li^(+)transport path.It is hoped that this article can enlighten profound thinking and open up new ways to improve the ionic conductivity of SPEs.

Solid polymer electrolytes in all-solid-state lithium metal batteries:From microstructures to properties

All-solid-state lithium(Li)metal batteries(ASSLMBs)are considered one of the most promising secondary batteries due to their high theoretical capacity and high safety performance.However,low room-temperature ionic conductivity and poor interfacial stability are two key factors affecting the practical application of ASSLMBs,and our understanding of the mechanisms behind these key problems from microscopic perspective is still limited.In this review,the mechanisms and advanced characterization techniques of ASSLMBs are summarized to correlate the microstructures and properties.Firstly,we summarize the challenges faced by solid polymer electrolytes(SPEs)in ASSLMBs,such as the low roomtemperature ionic conductivity and the poor interfacial stability.Secondly,several typical improvement methods of polymer ASSLMBs are discussed,including composite SPEs,ultra-thin SPEs,SPEs surface modification and Li anode surface modification.Finally,we conclude the characterizations for correlating the microstructures and the properties of SPEs,with emphasis on the use of emerging advanced techniques(e.g.,cryo-transmission electron microscopy)for in-depth analyzing ASSLMBs.The influence of the microstructures on the properties is very important.Until now,it has been difficult for us to understand the microstructures of batteries.However,some recent studies have demonstrated that we have a better understanding of the microstructures of batteries.Then we suggest that in situ characterization,nondestructive characterization and sub-angstrom resolution are the key technologies to help us further understand the batteries'microstructures and promote the development of batteries.And potential investigations to understand the microstructures evolution and the batteries behaviors are also prospected to expect further reasonable theoretical guidance for the design of ASSLMBs with ideal performance.

Polymer dispersed ionic liquid electrolytes with high ionic conductivity for ultrastable solid-state lithium batteries

Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for building solid-state lithium batteries due to their excellent flexibility,scalability,and interfacial compatibility with electrodes.However,the low ionic conductivity and poor cyclic stability of SPEs do not meet the requirements for practical applications of lithium batteries.Here,a novel polymer dispersed ionic liquid-based solid polymer electrolyte(PDIL-SPE)is fabricated using the in situ polymerization-induced phase separation(PIPS)method.The as-prepared PDIL-SPE possesses both outstanding ionic conductivity(0.74 mS cm^(-1) at 25℃)and a wide electrochemical window(up to 4.86 V),and the formed unique three-dimensional(3D)co-continuous structure of polymer matrix and ionic liquid in PDIL-SPE can promote the transport of lithium ions.Also,the 3D co-continuous structure of PDIL-SPE effectively accommodates the severe volume expansion for prolonged lithium plating and stripping processes over 1000 h at 0.5 mA cm^(-2) under 25℃.Moreover,the LiFePO_(4)//Li coin cell can work stably over 150 cycles at a 1 C rate under room temperature with a capacity retention of 90.6%from 111.1 to 100.7 mAh g^(-1).The PDIL-SPE composite is a promising material system for enabling the ultrastable operation of solid-state lithium-metal batteries.

A critical review on composite solid electrolytes for lithium batteries:Design strategies and interface engineering

The rapid development of new energy vehicles and 5G communication technologies has led to higher demands for the safety,energy density,and cycle performance of lithium-ion batteries as power sources.However,the currently used liquid carbonate compounds in commercial lithium-ion battery electrolytes pose potential safety hazards such as leakage,swelling,corrosion,and flammability.Solid electrolytes can be used to mitigate these risks and create a safer lithium battery.Furthermore,high-energy density can be achieved by using solid electrolytes along with high-voltage cathode and metal lithium anode.Two types of solid electrolytes are generally used:inorganic solid electrolytes and polymer solid electrolytes.Inorganic solid electrolytes have high ionic conductivity,electrochemical stability window,and mechanical strength,but suffer from large solid/solid contact resistance between the electrode and electrolyte.Polymer solid electrolytes have good flexibility,processability,and contact interface properties,but low room temperature ionic conductivity,necessitating operation at elevated temperatures.Composite solid electrolytes(CSEs) are a promising alternative because they offer light weight and flexibility,like polymers,as well as the strength and stability of inorganic electrolytes.This paper presents a comprehensive review of recent advances in CSEs to help researchers optimize CSE composition and interactions for practical applications.It covers the development history of solid-state electrolytes,CSE properties with respect to nanofillers,morphology,and polymer types,and also discusses the lithium-ion transport mechanism of the composite electrolyte,and the methods of engineering interfaces with the positive and negative electrodes.Overall,the paper aims to provide an outlook on the potential applications of CSEs in solid-state lithium batteries,and to inspire further research aimed at the development of more systematic optimization strategies for CSEs.

Self-assembly synthesis of solid polymer electrolyte with carbonate terminated poly (ethylene glycol) matrix and its application for solid state lithium battery

A facile one-pot synthesis of solid polymer electrolytes(SPEs), composed of carbonate terminated poly(ethylene glycol)(CH3O-PEG-IC), poly(ethylene glycol)-block-polystyrene(PEG-b-PS) block copolymer nanoparticles containing a conductive PEG corona, fumed SiO2 and Li TFSI salt via polymerization-induced self-assembly is proposed. This method to prepare SPEs has the advantages of one-pot convenient synthesis, avoiding use of organic solvent and conveniently adding inorganic additives. CH3O-PEG-IC combines advantages of PEG and polycarbonate, the in situ synthesized PEG-b-PS nanoparticles containing a rigid polystyrene(PS) core and a PEG corona guarantee continuous lithium ion transport in the synthesized SPEs, and the fumed SiO2 optimizes the interfacial properties and improves the electrochemical stability, all of which afford SPEs a well considerable room temperature ionic conductivity of 1.73 × 10^-4S/cm, high lithium transference number of 0.53, and wide electrochemical stability window of 5.5 V(vs. Li^+/Li). By employing these SPEs, the assembled solid state cells of Li FePO4 |SPEs|Li exhibit considerable cell performance.

Ameliorating the interfacial issues of all-solid-state lithium metal batteries by constructing polymer/inorganic composite electrolyte

Lithium metal is one of the most promising anodes for next-generation batteries due to its high capacity and low reduction potential.However,the notorious Li dendrites can cause the short life span and safety issues,hindering the extensive application of lithium batteries.Herein,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)ceramics are integrated into polyethylene oxide(PEO)to construct a facile polymer/inorganic composite solid-state electrolyte(CSSE)to inhibit the growth of Li dendrites and widen the electrochemical stability window.Given the feasibility of our strategy,the designed PEO-LLZO-LiTFSI composite solid-state electrolyte(PLLCSSE)exhibits an outstanding cycling property of 134.2 mAh g^(-1) after 500 cycles and the Coulombic efficiency of 99.1%after 1000 cycles at 1 C in LiFePO_(4)-Li cell.When cooperated with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode,the PLL-CSSE renders a capacity retention of 82.4%after 200 cycles at 0.2 C.More importantly,the uniform dispersion of LLZO in PEO matrix is tentative tested via Raman and FT-IR spectra and should be responsible for the improved electrochemical performance.The same conclusion can be drawn from the interface investigation after cycling.This work presents an intriguing solid-state electrolyte with high electrochemical performance,which will boost the development of all-solid-state lithium batteries with high energy density.

In-situ constructed polymer/alloy composite with high ionic conductivity as an artificial solid electrolyte interphase to stabilize lithium metal anode

Lithium(Li)metal is regarded as the best anode material for lithium metal batteries(LMBs)due to its high theoretical specific capacity and low redox potential.However,the notorious dendrites growth and extreme instability of the solid electrolyte interphase(SEI)layers have severely retarded the commercialization process of LMBs.Herein,a double-layered polymer/alloy composite artificial SEI composed of a robust poly(1,3-dioxolane)(PDOL)protective layer,Sn and LiCl nanoparticles,denoted as PDOL@Sn-LiCl,is fabricated by the combination of in-situ substitution and polymerization processes on the surface of Li metal anode.The lithiophilic Sn-LiCl multiphase can supply plenty of Li-ion transport channels,contributing to the homogeneous nucleation and dense accumulation of Li metal.The mechanically tough PDOL layer can maintain the stability and compact structure of the inorganic layer in the long-term cycling,and suppress the volume fluctuation and dendrites formation of the Li metal anode.As a result,the symmetrical cell under the double-layered artificial SEI protection shows excellent cycling stability of 300 h at 5.0 mA·cm^(−2)for 1 mAh·cm^(−2).Notably,the Li||LiFePO_(4)full cell also exhibits enhanced capacity retention of 150.1 mAh·g^(−1)after 600 cycles at 1.0 C.Additionally,the protected Li foil can effectively resist the air and water corrosion,signifying the safe operation of Li metal in practical applications.This present finding proposed a different tactic to achieve safe and dendrite-free Li metal anodes with excellent cycling stability.

A novel permselective organo-polysulfides/PVDF gel polymer electrolyte enables stable lithium anode for lithium–sulfur batteries

Lithium-sulfur(Li-S)battery can satisfy the need of the future power battery market because of its high energy density,but the hidden dangers caused by lithium anode have seriously hindered their commercialization.Herein,an innovative gel polymer electrolyte(GPE)composed of polyvinylidene fluoride(PVDF)and organo-polysulfide polymer(PSPEG)is proposed,which could be used in semisolid-state Li-S batteries for protection of Li anodes.Particularly,organo-polysulfide polymer could chemically/electrochemically generate both inorganic and organic components simultaneously in-situ once contacting fresh Li metal surface and/or during discharging processes.And these inorganic/organic components could participate in the formation of the SEI layer and finally constitute a stable and flexible hybrid SEI layer on the surface of Li metal anode.Moreover,the organic components were permselective to lithium ions against anions.Therefore,PVDF/PSPEG GPE ensures the ideal chemical and electrochemical properties for Li-S batteries.Our work demonstrates an effective solution to solve the problems about Li anodes and contributes to the development of the safe Li metal batteries.

Synthetic poly-dioxolane as universal solid electrolyte interphase for stable lithium metal anodes

Lithium (Li) metal is a promising anode for the next generation high-energy–density batteries. However, the growth of Li dendrites, low coulombic efficiency and dramatic volume change limit its development. Here, we report a new synthetic poly-dioxolane (PDOL) approach to constructing an artificial 'elastic' SEI to stabilize the Li/electrolyte interface and the Li deposition/dissolution behavior in a variety of electrolytes. By coating PDOL with optimized molecular weights and synthetic routes on Li metal anode, the 'elastic' SEI layer could be maintained on top of the Li metal anode to accommodate the Li deposition/dissolution. No dendrite formation was observed during the cycling process, and the interfacial side reactions were reduced significantly. Consequently, we successfully achieved 330 cycles with a CE of 98.4% in ether electrolytes and 90 cycles with a CE of 94.3% in carbonate electrolytes. Simultaneously, the Li-metal batteries with LiFePO_(4) as cathodes also exhibited improved cycling performance. This strategy could promote the development of dendrite-free metal anodes toward high-performance Li-metal batteries.

All-solid-state lithium batteries with inorganic solid electrolytes:Review of fundamental science

The scientific basis of all-solid-state lithium batteries with inorganic solid electrolytes is reviewed briefly, touching upon solid electrolytes, electrode materials, electrolyte/electrode interface phenomena, fabrication, and evaluation. The challenges and prospects are outlined as well.

Gas‐phase fluorination of conjugated microporous polymer microspheres for effective interfacial stabilization in lithium metal anodes

Lithium(Li)metal anodes have attracted extensive attention due to their ultrahigh theoretical capacity and low potential.However,the uneven deposition of Li near the unstable electrode/electrolyte interfaces leads to the growth of Li dendrites and the degradation of active electrodes.Herein,we directly fluorinate alkyne-containing conjugated microporous polymers(ACMPs)microspheres with fluorine gas(F_(2))to introduce a novel fluorinated interlayer as an interfacial stabilizer in lithium metal batteries.Using density functional theory methods,it is found that as-prepared fluorinated ACMP(FACMP)has abundant partially ionic C–F bonds.The C–F bonds with electrochemical lability yield remarkable lithiophilicity during cycling.The in situ reactions between the active C–F bonds and Li ions enable transfer of lithium fluoride microcrystals to the solid electrolyte interphase(SEI)layers,guaranteeing effective ionic distribution and smooth Li deposition.Consequently,Li metal electrodes with the fluorinated interlayers demonstrate excellent cycling performances in both half-batteries and full cells with a lithium bis(trifluoromethanesulfonyl)imide electrolyte as well as a nonfluorinated lithium bis(oxalate)borate electrolyte system.This strategy is highly significant in customizable SEI layers to stabilize electrode interfaces and ensure high utilization of Li metal anodes,especially in a nonfluorinated electrolyte.

A flexible, robust, and high ion-conducting solid electrolyte membranes enabled by interpenetrated network structure for all-solid-state lithium metal battery

Poly(vinyl alcohol)/poly(ethylene glycol)(PVA/PEG) semi-interpenetrating networks(s-IPN) were synthesized for the application of solid electrolyte membranes of lithium metal batteries. Thermal, mechanical and dimensional stability, lithium-ion conductivity, interfacial compatibility, and cell performance were evaluated to assure their application. As this s-IPN structure suppressed the crystallinity by formation of network structure, both the lithium-ion conductivity and mechanical strength were simultaneously enhanced. The PVA/PEG-3s-IPN showed the highest lithium-ion conductivity of 3.26 × 10^(-4)S cm^(-1)in a wide electrochemical window(5.8 V vs. Li/Li^(+)), maintaining the robust solid-state with the tensile strength beyond 16.2 MPa at room temperature. The synthesized solid electrolyte membranes exhibited quite high specific capacity over 122 m Ah g^(-1)at 0.1 C from Li|PVA/PEG-3s-IPN|LiFePO_(4) cell and the long-term stable lithium stripping/plating performance for 1000 cycles from Li symmetric cell.

ZIF-8-functionalized polymer electrolyte with enhanced performance for high-temperature solid-state lithium metal batteries

Solid polymer electrolytes(SPEs)with high ionic conductivity are desirable for solid-state lithium metal batteries(SSLMBs)to achieve enhanced safety and energy density.Incorporating nanofillers into a polymeric matrix to develop nanocomposite solid electrolytes(NCSEs)has become a promising method for improving the ionic conductivity of the SPEs.Here,a novel ZIF-8-functionalized NCSE was prepared for high-temperature S SLMB s using an in situ radical polymerization method.It is found that the ZIF-8 nanoparticles could reduce the crystallinity of polymer segments and offer a Lewis acid surface that promotes the dissociation of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)and stabilizes the TFSI^(-) anion movement.Thus,the as-prepared NCSE exhibits an outstanding ionic conductivity of 1.63×10^(-3)S·cm^(-1),an electrochem ical stability window of 5.0 V at 80℃,and excellent interface compatibility with lithium metal anode with a stable polarization over 2000 h.Furthermore,the assembled SSLMBs with LiFePO_(4)cathode show dendrite-free Li-metal surface,good rate capability,and stable cycling stability with a capacity retention of 70%over 1000 cycles at a high temperature of 80℃.This work provides valuable insights into promoting the ionic conductivity of SPEs.

Porous garnet as filler of solid polymer electrolytes to enhance the performance of solid-state lithium batteries

In order to enhance the ionic conductivity of solid polymer electrolytes(SPEs)and their structural rigidity against lithium dendrite during lithium-ion battery(LIB)cycling,we propose porous garnet Li6.4La3Zr2Al0.2O12(LLZO),as the filler to SPEs.The porous LLZO with interlinked grains was synthesized via a resol-assisted cationic coordinative co-assembly approach.The porous structure of LLZO with high specific surface area facilitates the interaction between polymer and filler and provides sufficient entrance for Li^(+)migration into the LLZO phase.Furthermore,the interconnection of LLZO grains forms continuous inorganic pathways for fast Li^(+)migration,which avoid the multiple diffusion for Li^(+)in interface.As a result,the SPEs with porous LLZO(SPE-PL)show a high ionic conductive of 0.73 mS·cm^(-1) at 30℃ and lithium-ion transference number of 0.40.The porous LLZO with uniformly dispersed pores also acts as an ion distributor to regulate ionic flux.The lithium-symmetrical batteries assembled with SPE-PL show a highly stable Li plating/stripping cycling for nearly 3000 h at 0.1 mA·cm^(-2).The corresponding Li/LiFePO_(4) batteries also exhibit excellent cyclic performance with capacity retention of 75%after nearly 500 cycles.This work brings new insights into the design of conductive fillers and the optimization of SPEs.