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The solid‐state batteries (SSBs) with Li anode present one of the most promising energy storage systems due to their enhanced energy density and safety. However, interfacial problems between Li anode and solid‐state electrolyte hinder the advancement of SSBs. Among them, insufficient solid‐solid interfacial contact is the main issue, which causes large resistance and hinders Li+ diffusion, leading to current distribution unevenness and lithium dendrites growth. To meet these challenges, a silver/carbon interlayer composed of ultrafine Ag nanoparticles (≈5 nm) grown on COOH‐CNTs (nano‐Ag@COOH‐CNTs) is constructed. In which, nano‐Ag is designed to guide homogeneous Li deposition, while CNTs substrate bonds with Li6.5La3Zr1.5Ta0.5O12 (LLZTO) electrolyte by reactions between ─COOH groups and LLZTO alkaline surface, thus transforming loose physical solid‐solid contact to chemical bonding contact. In addition, nano‐Ag is immobilized by CNTs, avoiding the migration of Li+ implanted nano‐Ag during cycling. Therefore, nano‐Ag@COOH‐CNTs interlayer can boost Li+ transport at LLZTO/Li interface and inhibit Li dendrites, achieving an ultra‐low interfacial resistance of 0.25 Ω cm2, a high critical current density of 1.7 mA cm−2 and a long cycling over 2155 h at 0.5 mA cm−2. The modified SSBs with LiNi0.83Co0.12Mn0.05O2 cathode cycles stably over 500 cycles. Moreover, high‐loading SSBs operate stably for 85 cycles. [ABSTRACT FROM AUTHOR]

The solid‐state batteries (SSBs) with Li anode present one of the most promising energy storage systems due to their enhanced energy density and safety. However, interfacial problems between Li anode and solid‐state electrolyte hinder the advancement of SSBs. Among them, insufficient solid‐solid interfacial contact is the main issue, which causes large resistance and hinders Li+ diffusion, leading to current distribution unevenness and lithium dendrites growth. To meet these challenges, a silver/carbon interlayer composed of ultrafine Ag nanoparticles (≈5 nm) grown on COOH‐CNTs (nano‐Ag@COOH‐CNTs) is constructed. In which, nano‐Ag is designed to guide homogeneous Li deposition, while CNTs substrate bonds with Li6.5La3Zr1.5Ta0.5O12 (LLZTO) electrolyte by reactions between ─COOH groups and LLZTO alkaline surface, thus transforming loose physical solid‐solid contact to chemical bonding contact. In addition, nano‐Ag is immobilized by CNTs, avoiding the migration of Li+ implanted nano‐Ag during cycling. Therefore, nano‐Ag@COOH‐CNTs interlayer can boost Li+ transport at LLZTO/Li interface and inhibit Li dendrites, achieving an ultra‐low interfacial resistance of 0.25 Ω cm2, a high critical current density of 1.7 mA cm−2 and a long cycling over 2155 h at 0.5 mA cm−2. The modified SSBs with LiNi0.83Co0.12Mn0.05O2 cathode cycles stably over 500 cycles. Moreover, high‐loading SSBs operate stably for 85 cycles. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium metal batteries (ASSLMBs) featuring sulfide solid electrolytes (SEs) are recognized as the most promising next‐generation energy storage technology because of their exceptional safety and much‐improved energy density. However, lithium dendrite growth in sulfide SEs and their poor air stability have posed significant obstacles to the advancement of sulfide‐based ASSLMBs. Here, a thin layer (approximately 5 nm) of g‐C3N4 is coated on the surface of a sulfide SE (Li6PS5Cl), which not only lowers the electronic conductivity of Li6PS5Cl but also achieves remarkable interface stability by facilitating the in situ formation of ion‐conductive Li3N at the Li/Li6PS5Cl interface. Additionally, the g‐C3N4 coating on the surface can substantially reduce the formation of H2S when Li6PS5Cl is exposed to humid air. As a result, Li–Li symmetrical cells using g‐C3N4‐coated Li6PS5Cl stably cycle for 1000 h with a current density of 0.2 mA cm−2. ASSLMBs paired with LiNbO3‐coated LiNi0.6Mn0.2Co0.2O2 exhibit a capacity of 132.8 mAh g−1 at 0.1 C and a high‐capacity retention of 99.1% after 200 cycles. Furthermore, g‐C3N4‐coated Li6PS5Cl effectively mitigates the self‐discharge behavior observed in ASSLMBs. This surface‐coating approach for sulfide solid electrolytes opens the door to the practical implementation of sulfide‐based ASSLMBs. [ABSTRACT FROM AUTHOR]

Cubic phase Li 7 La 3 Zr 2 O 12 (LLZO) is a promising electrolyte material for all-solid-state rechargeable lithium-ion batteries. The homogeneous densification of the garnet solid electrolyte ceramic material is crucial for enhancing its ionic conductivity performance. Herein, an Al/Ta co-doped strategy is employed to stabilize the cubic phase structure of LLZO and is combined with a two-step sintering method to enhance densification, in order to investigate its effect on microstructure, ionic conductivity, and electrochemical properties. During the formation process, amorphous Li 2 O reacts with doped Al 2 O 3 to create a Li–Al–O liquid phase at the grain boundaries. Combined with two-step sintering to ensure that the desired material transformation is achieved, resulting in a dense microstructure and better mechanical properties. The solid electrolyte Li 6.4 Al 0.1 La 3 Zr 1.7 Ta 0.3 O 12 under two-step sintering (LLZATO-2) is successfully synthesized, delivering an ionic conductivity up to 7.33 × 10−4 S cm−1 at room temperature and an activation energy of 0.22 eV. This work also highlights the critical role of co-doping combined with two-step sintering in preparing well-performing solid-state electrolytes and all-solid-state lithium-ion batteries. LLZO solid electrolyte with lithium ion conductivity is prepared by Al/Ta co-doped combined with two-step sintering. The experimental and theoretical results indicate that amorphous Li 2 O reacts with Al 2 O 3 to form a Li–Al–O liquid phase at the grain boundaries, filling the pores generated at the grain boundaries. The two-step sintering further suppresses grain growth and promotes densification growth. [Display omitted] [ABSTRACT FROM AUTHOR]

Solid‐state lithium metal batteries (SSLMBs) with polymer electrolytes (SPEs) have attracted tremendous attention owing to their superior safety and high energy density. However, the unstable solid electrolyte interphase (SEI) between Lithium (Li) and SPEs hinders their practical application. Herein, an innovative interfacial catalysis strategy is applied to the in situ construction of a multifunctional inorganic‐rich SEI. The transfer of unpaired electrons adjacent to calcium vacancies (VCa) to the TFSI− anion promotes the breaking of S─N and C─F bonds during the electrochemical decomposition of TFSI−, thus enhancing its decomposition kinetics. The inorganic‐rich SEI derived from TFSI− is super‐stable and kinetically favorable for fast and homogeneous transport of Li ions, thereby hindering the growth of lithium dendrites. Consequently, the interfacial catalysis strategy endows Li||Li symmetric cells, LFP||Li and NCM811||Li full batteries with enhanced cyclability. Thus, this work expands the interfacial catalysis strategy to a platform for designing multifunctional SEI in long‐life SSLMB. [ABSTRACT FROM AUTHOR]

The inherent low ionic conductivity of PVDF‐based electrolytes at room temperature and lithium dendrite penetration hinder its further application. Herein, a LaF3 doped Poly(vinylidene fluoride‐chlorotrifluoroethylene) (P(VDF‐ctfe)) quasi‐solid electrolyte is developed. High‐flux channels are created due to the optimization of the lithium environment that lanthanum preferentially competes coordination with anionic species for relaxing lithium hopping. Lithium carriers are therefore highly free and unbound at the molecular level, resulting in a high ionic conductivity (σ) of 0.7 mS cm−1 and a transfer number (tLi+) of 0.79 at 25 °C. Moreover, the in situ organic–inorganic LiF‐rich dielectric layer effectively improves the stability and compatibility of the electrode/electrolyte interface, ensuring interfacial lithium conduction while facilitating stable Li+ plating/stripping. As a result, the optimized Li/ATCSE‐3%/Li can deliver favorable compatibility at 0.1 and 0.3 mA cm−2 for stable Li+ plating/stripping for 2000 and 1200 h, respectively. The high‐mass loading (6.4 mg cm−2) pouch cell delivers a stable cycling performance over 100 cycles with a capacity retention of 85.8% at 0.3 °C. This work is anticipated to provide considerable insight into the creative design of lithium transport of polymer‐based for practical quasi‐solid‐state lithium metal batteries. [ABSTRACT FROM AUTHOR]

Adapting solid‐state Li‐metal batteries is an attractive way to pursue higher energy density and safety compared to liquid‐based ones. With high ionic conductivity and excellent stability with Li, Ta‐doped Li7La3Zr2O12 (LLZTO) is an effective option. However, the poor solid–solid interface contact induced by the lithiophobic Li2CO3 layer hinder its practical application. Herein, a versatile strategy is proposed based on the hydrolysis of sodium tetrafluoroborate (NaBF4), aiming to convert the Li2CO3 into multifunctional hybrid layer containing LiF, LiBO2, and NaF. Among them, LiF and LiBO2 serve as the primary Li ion conductors, the introduction of NaF with high surface energy not only enhances the interface wettability, but also further elevates the critical dendrite strength against Li dendrites. All three components serve as excellent electronic insulators, suppressing electron invasion at the interface and preventing Li dendrite growth in the solid electrolyte. As expected, the interfacial impedance of the NaBF4 treated symmetric cell is reduced to 6.0 Ω cm2, the critical current density (CCD) comes to 2.0 mA cm−2, and cycles over 3000 h at 0.3 mA cm−2 and 1500 h at 0.5 mA cm−2 respectively. Besides, the modified SSBs matched with LiFePO4 or LiNi0.6Co0.2Mn0.2O2 cathode show great long‐term cycling and rate performance. [ABSTRACT FROM AUTHOR]

Solid‐state lithium metal batteries (SSLMBs) with poly (ethylene oxide) (PEO)‐based electrolytes have increasingly become one of the most promising battery technologies due to high energy density and safety. However, adverse electrode/electrolyte interface compatibility issues hinder further application. Herein, a PEO‐based composite solid electrolyte with excellent anode and cathode interfacial compatibility is designed via the coordination modulation strategy induced by lithium difluorobis(oxalato)phosphate (DFBOP). By utilizing this electrolyte, the robust inorganic‐rich interphase involving LiF, LixPOyFz, and P─O components is in situ generated on lithium (Li) anode and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode surfaces via forceful coordination among PEO, lithium bis(trifluoromethanesulphonyl)imide, and DFBOP and subsequent adjustment of front orbital energy levels. It contributes to homogeneous lithium deposition and an effective impediment of PEO oxidation decomposition at high voltage, promoting superior interfacial stability. Consequently, Li‐symmetric cells with modified electrolyte can achieve a stable cycle over 7000 h at 0.2 mA cm−2. Specially, the cathode electrolyte interphase with a unique organic–inorganic interpenetration network structure enables the 4.5 V Li/NCM811 cells to cycle steadily over 100 cycles, with a high discharge capacity of 215.4 mAh g−1 and initial coulombic efficiency of 91.23%. This research has shed light on the interfacial design of PEO‐based electrolytes from the perspective of electrolyte coordination regulation to construct high‐performance SSLMBs. [ABSTRACT FROM AUTHOR]

The conventional covalent organic framework (COF)‐based electrolytes with tailored ionic conducting behaviors are typically fabricated in the powder morphology, requiring further compaction procedures to operate as solid electrolyte tablets, which hinders the large‐scale manufacturing of COF materials. In this study, we present a feasible electrospinning strategy to prepare scalable, self‐supporting COF membranes (COMs) that feature a rigid COF skeleton bonded with flexible, lithiophilic polyethylene glycol (PEG) chains, forming an ion conduction network for Li+ transport. The resulting PEG‐COM electrolytes exhibit enhanced dendrite inhibition and high ionic conductivity of 0.153 mS cm−1 at 30 °C. The improved Li+ conduction in PEG‐COM electrolytes stems from the loose ion pairing in the structure and the production of higher free Li+ content, as confirmed by solid‐state 7Li NMR experiments. These changes in the local microenvironment of Li+ facilitate its directional movement within the COM pores. Consequently, solid‐state symmetrical Li|Li, Li|LFP, and pouch cells demonstrate excellent electrochemical performance at 60 °C. This strategy offers a universal approach for constructing scalable COM‐based electrolytes, thereby broadening the practical applications of COFs in solid‐state lithium metal batteries. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium metal batteries (ASSLMBs) with solid electrolytes (SEs) have emerged as a promising alternative to liquid electrolyte‐based Li‐ion batteries due to their higher energy density and safety. However, since ASSLMBs lack the wetting properties of liquid electrolytes, they require stacking pressure to prevent contact loss between electrodes and SEs. Though previous studies showed that stacking pressure could impact certain performance aspects, a comprehensive investigation into the effects of stacking pressure has not been conducted. To address this gap, we utilized the Li6PS5Cl solid electrolyte as a reference and investigated the effects of stacking pressures on the performance of SEs and ASSLMBs. We also developed models to explain the underlying origin of these effects and predict battery performance, such as ionic conductivity and critical current density. Our results demonstrated that an appropriate stacking pressure is necessary to achieve optimal performance, and each step of applying pressure requires a specific pressure value. These findings can help explain discrepancies in the literature and provide guidance to establish standardized testing conditions and reporting benchmarks for ASSLMBs. Overall, this study contributes to the understanding of the impact of stacking pressure on the performance of ASSLMBs and highlights the importance of careful pressure optimization for optimal battery performance. [ABSTRACT FROM AUTHOR]

Highlights Ultra-thin asymmetric composite solid-state electrolytes with ultralight areal density were designed for solid-state lithium metal batteries, achieving interfacial stability to Li metal and high-voltage cathode. The improved mechanical properties of the electrolyte contribute to the inhibition of Li dendrite growth was demonstrated by both experimental and theoretical simulations. The assembled pouch cell exhibited a high gravimetric/volume energy density of 344.0 Wh kg−1/773.1 Wh L−1.

In solid‐state lithium metal batteries (SSLMBs), the inhomogeneous electrolyte‐electrode interphase layer aggravates the interfacial stability, leading to discontinuous interfacial ion/charge transport and continuous degradation of the electrolyte. Herein, we constructed an anion‐modulated ionic conductor (AMIC) that enables in situ construction of electrolyte/electrode interphases for high‐voltage SSLMBs by exploiting conformational transitions under multiple interactions between polymer and lithium salt anions. Anions modulate the decomposition behavior of supramolecular poly (vinylene carbonate) (PVC) at the electrode interface by changing the spatial conformation of the polymer chains, which further enhances ion transport and stabilizes the interfacial morphology. In addition, the AMIC weakens the "Li+‐solvation" and increases Li+ vehicle sites, thereby enhancing the lithium‐ion transport number (tLi+=~0.67). Consequently, Li || LiNi0.8Co0.1Mn0.1O2 cell maintains about 85 % capacity retention and Coulombic efficiency >99.8 % in 200 cycles at a charge cut‐off voltage of 4.5 V. This study provides a new understanding of lithium salt anions regulating polymer chain segment behavior in the solid‐state polymer electrolyte (SPE) and highlights the importance of the ion environment in the construction of interfacial phases and ionic conduction. [ABSTRACT FROM AUTHOR]

Solid‐state polymer lithium metal batteries (SSLMBs) have attracted considerable attention because of their excellent safety and high energy density. However, the application of SSLMBs is significantly impeded by uneven Li deposition at the interface between solid‐state electrolytes and lithium metal anode, especially at a low temperature. Herein, this issue is addressed by designing an agarose‐based solid polymer electrolyte containing branched structure. The star‐structured polymer is synthesized by grafting poly (ethylene glycol) monomethyl‐ether methacrylate and lithium 2‐acrylamido‐2‐methylpropanesulfonate onto tannic acid. The star structure regulates Li‐ion flux in the bulk of the electrolyte and at the electrolyte/electrode interfaces. This unique omnidirectional Li‐ion transportation effectively improves ionic conductivity, facilitates a uniform Li‐ion flux, inhibits Li dendrite growth, and alleviates polarization. As a result, a solid‐state LiFePO4||Li battery with the electrolyte exhibits outstanding cyclability with a specific capacity of 134 mAh g−1 at 0.5C after 800 cycles. The battery shows a high discharge capacity of 145 mAh g−1 at 0.1 C after 200 cycles, even at 0 °C. The study offers a promising strategy to address the uneven Li deposition at the solid‐state electrolyte/electrode interface, which has potential applications in long‐life solid‐state lithium metal batteries at a low temperature. [ABSTRACT FROM AUTHOR]

Highlights: Ultra-thin asymmetric composite solid-state electrolytes with ultralight areal density were designed for solid-state lithium metal batteries, achieving interfacial stability to Li metal and high-voltage cathode. The improved mechanical properties of the electrolyte contribute to the inhibition of Li dendrite growth was demonstrated by both experimental and theoretical simulations. The assembled pouch cell exhibited a high gravimetric/volume energy density of 344.0 Wh kg−1/773.1 Wh L−1. 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 high-energy–density of SSLMBs. Herein, we develop an ultrathin (12.6 µm) 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. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF)‐based polymer electro‐lytes are attracting increasing attention for high‐voltage solid‐state lithium metal batteries because of their high room temperature ionic conductivity, adequate mechanical strength and good thermal stability. However, the presence of highly reactive residual solvents, such as N, N‐dimethylformamide (DMF), severely jeopardizes the long‐term cycling stability. Herein, we propose a solvation‐tailoring strategy to confine residual solvent molecules by introducing low‐cost 3 Å zeolite molecular sieves as fillers. The strong interaction between DMF and the molecular sieve weakens the ability of DMF to participate in the solvation of Li+, leading to more anions being involved in solvation. Benefiting from the tailored anion‐rich coordination environment, the interfacial side reactions with the lithium anode and high‐voltage NCM811 cathode are effectively suppressed. As a result, the solid‐state Li||Li symmetrical cells demonstrates ultra‐stable cycling over 5100 h at 0.1 mA cm−2, and the Li||NCM811 full cells achieve excellent cycling stability for more than 1130 and 250 cycles under the charging cut‐off voltages of 4.3 V and 4.5 V, respectively. Our work is an innovative exploration to address the negative effects of residual DMF in PVDF‐based solid‐state electrolytes and highlights the importance of modulating the solvation structures in solid‐state polymer electrolytes. [ABSTRACT FROM AUTHOR]

Polymer electrolytes have great potential to realize solid‐state lithium metal batteries with high energy density and intrinsic safety. However, the poor mechanical strength and uncontrolled electrolyte/electrode interface cannot guarantee the stable operation during long‐term cycling. Herein, a supramolecular polyurethane material reinforced by aromatic charge‐transfer interactions is synthesized as electrolyte matrix with high stiffness, excellent toughness, and unique mechanical energy dissipation capacity. The optimized electrolyte network can dynamically adapt to the volume fluctuating Li metal and, importantly, eliminate stress‐concentrating behavior under deformed state. As a result, the Li/Li symmetric cells can stably work for more than 3500 h without short circuit. And the LiFePO4/Li batteries show superior electrochemical performance over 1200 cycles with a capacity retention of 95.4% at 0.33 C. The supramolecular approach to tune the mechanical properties of the polymers is believed to provide a new strategy for designing solid electrolytes with desirable comprehensive mechanical properties for solid‐state batteries. [ABSTRACT FROM AUTHOR]

KAP1 with porous surface structure and reasonable hydrogen bonding are used as fillers in PEO-based CPEs that could solve the compatibility of fillers in polymer-based electrolytes and provide a valuable reference for the design of high-performance ASSLMBs. [Display omitted] Achieving practical applications of PEO-based composite solid electrolyte (CPE) batteries requires the precise design of filler structures at the molecular level to form stable composite interfacial phases, which in turn improve the conductivity of Li+ and inhibit the nucleation growth of lithium dendrites. Some functional fillers suffer from severe agglomeration due to poor compatibility with the polymer base or grain boundary migration, resulting in limited improvement in cell performance. In this paper, ILs@KAP1 is reported as a filler to enhance the performance of PEO-based batteries. Thereinto, the hypercrosslinked phosphorus ligand polymer-containing KAP1, designed at the molecular level, has an abundant porous structure, hydrogen bonding network, and a rigid skeleton structure of benzene rings. These can be used both to improve the flammability with PEO-based and to reduce the crystallinity of the polymer electrolyte. Ionic liquids (ILs) are encapsulated in the nanochannels of KAP1, and thus a 3D Li+ conducting framework could be formed. In this case, it could not only facilitate the wettability of the contact interface with the electrode, significantly promoting its compatibility and providing a fast Li+ transport path, but also facilitate the formation of LiF, Li 3 N and Li 2 O rich SEI components, further fostering the uniform deposition/exfoliation of lithium. The LFP||CPE||Li battery assembled with ILs@KAP1-PEO-CPE has a high initial discharge specific capacity about 156 mAh/g at 1C and a remaining capacity about 121.8 mAh/g after 300 cycles (capacity retention of 78.07%). [ABSTRACT FROM AUTHOR]

Achieving solid polymer electrolytes with ceramic‐like fast single‐ion conduction behavior, separator‐required mechanical properties, and good lithium‐dendrite suppression capability is essential but extremely challenging for the practical success of solid‐state lithium‐metal batteries. The key to overcome this long‐standing bottleneck is to rationally design the Li+‐transport microenvironment inside the polymeric ion‐conductors. Herein, the concept of a nano‐dipole doped composite polymer electrolyte (NDCPE) is proposed using surface‐charged halloysite nanotubes (d‐HNTs) as the dopant to achieve a Li+‐transport‐friendly microenvironment in poly(vinylidene fluoride) (PVDF) based quasi‐solid electrolytes. Results show that the d‐HNTs doping can immobilize the anions and help dissociate the lithium salt, which leads to an advanced dynamic Li+‐interface yielding both a high Li+‐transference number (0.75 ± 0.04) and ionic conductivity (0.29 ± 0.04 mS cm−1 @R.T.). Moreover, compared with the commercial separator, the NDCPE thin‐film shows similar toughness, mechanical strength, and puncture resistance, but much superior capability for stabilizing the lithium‐metal anode. To understand the possible doping mechanism, a hybrid Li+‐solvation model combining the surface charges of the nanofiller, absorbed solvent molecules, and absorbed polymer chain unit is proposed and discussed for guiding the future studies on advanced hybrid solid polymer electrolytes. [ABSTRACT FROM AUTHOR]

The deployment of lithium metal anode in solid‐state batteries with polymer electrolytes has been recognized as a promising approach to achieving high‐energy‐density technologies. However, the practical application of the polymer electrolytes is currently constrained by various challenges, including low ionic conductivity, inadequate electrochemical window, and poor interface stability. To address these issues, a novel eutectic‐based polymer electrolyte consisting of succinonitrile (SN) and poly (ethylene glycol) methyl ether acrylate (PEGMEA) is developed. The research results demonstrate that the interactions between SN and PEGMEA promote the dissociation of the lithium difluoro(oxalato) borate (LiDFOB) salt and increase the concentration of free Li+. The well‐designed eutectic‐based PAN1.2‐SPE (PEGMEA: SN=1: 1.2 mass ratio) exhibits high ionic conductivity of 1.30 mS cm−1 at 30 °C and superior interface stability with Li anode. The Li/Li symmetric cell based on PAN1.2‐SPE enables long‐term plating/stripping at 0.3 and 0.5 mA cm−2, and the Li/LiFePO4 cell achieves superior long‐term cycling stability (capacity retention of 80.3 % after 1500 cycles). Moreover, Li/LiFePO4 and Li/LiNi0.6Co0.2Mn0.2O2 pouch cells employing PAN1.2‐SPE demonstrate excellent cycling and safety characteristics. This study presents a new pathway for designing high‐performance polymer electrolytes and promotes the practical application of high‐stable lithium metal batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Solid-state electrolytes have been widely investigated for lithium batteries since they provide a high degree of safety. However, their low ionic conductivity and substantial growth of lithium dendrites hamper their commercial applications. Garnet-type Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) is one of the most promising active fillers to advance the performance of the solid polymer electrolyte. Nevertheless, their performance is still limited due to their large interfacial resistance. Herein, we embedded the amorphous Li 2 O 2 (LO) into LLZTO particles via the quenching process and successfully achieved an interfacial layer of Li 2 O 2 around LLZTO particles (LLZTO@LO). Amorphous Li 2 O 2 acts as a binder and showed an excellent affinity for Li+ ions which promotes their fast transference. Moreover, the stable and dense interfacial Li 2 O 2 layer enhances interfacial contact and suppresses the lithium dendrite growth during the long operation cycling process. The PEO/10LLZTO@2LO solid composite polymer electrolyte (SCPE) showed the highest ionic conductivity of 3.2 × 10-4 S cm−1 at 40 °C as compared to pristine LLZTO-based SCPE. Moreover, the Li│(PEO/10LLZTO@2LO) │Li symmetric cell showed a stable and smooth long lifespan up to 1100 h at 40 °C. Furthermore, the LiFePO 4 //Li full battery with PEO/10LLZTO@2LO SCPE demonstrated stable cycling performance for 400 cycles. These results constitute a significant step toward the practical application of solid-state lithium metal batteries (SS-LMBs). [ABSTRACT FROM AUTHOR]

Solid‐state lithium metal batteries (SSLMBs) are highly desirable for energy storage because of the urgent need for higher energy density and safer batteries. However, it remains a critical challenge for stable cycling of SSLMBs at low temperature. Here, a highly viscoelastic polyether‐b‐amide (PEO‐b‐PA) based composite solid‐state electrolyte is proposed through a one‐pot melt processing without solvent to address this key process. By adjusting the molar ratio of PEO‐b‐PA to lithium bis(trifluoromethanesulphonyl)imide (ethylene oxide:Li = 6:1) and adding 20 wt.% succinonitrile, fast Li+ transport channel is conducted within the homogeneous polymer electrolyte, which enables its application at ultra‐low temperature (−20 to 25 °C). The composite solid‐state electrolyte utilizes dynamic hydrogen‐bonding domains and ion‐conducting domains to achieve a low interfacial charge transfer resistance (<600 Ω) at −20 °C and high ionic conductivity (25 °C, 3.7 × 10−4 S cm−1). As a result, the LiFePO4|Li battery based on composite electrolyte exhibits outstanding electrochemical performance with 81.5% capacity retention after 1200 cycles at −20 °C and high discharge specific capacities of 141.1 mAh g−1 with high loading (16.1 mg cm−2) at 25 °C. Moreover, the solid‐state SNCM811|Li cell achieves excellent safety performance under nail penetration test, showing great promise for practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional polymer electrolyte (MPE) buffer layer is constructed on LLZTO surface through an in-situ crosslinking strategy. • MPE improves interface contact at both sides of LLZTO and widen electrochemical window. • MPE@LLZTO facilitates uniform Li+ deposition/exfoliation and inhibits dendrite growth. • The Li symmetrical and NCM523 full cells exhibit excellent cycle performance at 30 °C. The garnet Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) is one of the most promising electrolytes for commercial application since of its high ionic conductivity and good stability to Li. Nevertheless, the poor electrolyte/electrode interface contact enlarges the interface impedance of all-solid-state battery (ASSB). Herein, a multifunctional polymer electrolyte (MPE) interface buffer layers are formed on both sides of LLZTO surface through an in-situ crosslinking strategy to improve the interface contact with electrodes, which can facilitate uniform Li+ deposition/exfoliation and inhibit the growth of lithium dendrites as evidenced by the reduced interface impedance (103.4 Ω cm2), the increased critical current density (CDD, 1.2 mA cm−2) and 950 h stable cycle of Li symmetric cells at 0.7 mA cm−2, 0.7 mA h cm−2. Besides, the MPE layer can reduce the magnitude of electric field at the interface and widen the electrochemical window (0∼5.2 V). The stable interface of the LLZTO@MPE/cathode enables the full cells matching with the LiFePO 4 (LFP) and LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cathodes to deliver superior electrochemical performances. Specifically, the Li/MPE@LLZTO@MPE/LFP delivers a capacity retention rate of 87% after 200 cycles at 1 C. When it's matched with the NCM523 cathode, a capacity retention rate of 98% is retained after 100 cycles at 1 C. This work provides an effective and simple way to build good-interface-contact and long-lifespan garnet solid-state lithium metal batteries (SSLMBs). [ABSTRACT FROM AUTHOR]

[Display omitted] An in-depth understanding of the degradation mechanisms is a prerequisite for developing the next-generation all solid-state lithium metal battery (ASSLMB) technology. Herein, synchrotron X-ray computed tomography (SXCT) together with other probing tools and simulation method were employed to rediscover the decaying mechanisms of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM)|Li 6 PS 5 Cl (LPSCl)|Li ASSLMB. It reveals that the detachment and isolation of NCM particles cause the current focusing on the remaining active regions of cathode. The extent of Li stripping and the likelihood of Li+ plating into LPSCl facing the active NCM particles becomes higher. Besides, the homogeneity of Li stripping/plating is improved by homogenizing the electrochemical reactions at the cathode side by LiZr 2 (PO 4) 3 (LZP) coating. These results suggest a codependent failure mechanism between cathode and anode that is mediated by uneven Li ion flux. This work contributes to a holistic understanding of the degradation mechanisms in ASSLMBs and opens new opportunities for their further optimization and development. [ABSTRACT FROM AUTHOR]

The solid‐state electrolyte is a promising candidate for advancing the dual goals of high energy density and high safety for batteries. However, it is difficult for current solid electrolyte systems to balance the high ion transport, mechanical strength, thermal safety, and electrochemical stability simultaneously, which will greatly restrict their scale‐up and practical applications in batteries. Herein, a sandwich‐type hybrid solid polymer electrolytes (SHSPEs) is prepared via a simple coating method, the gel polymer filled in the middle porous polyethylene (PE) separator endows SHSPEs fast ion transport (7.13 × 10−4 S cm−1, 25 °C) and good mechanical properties (205.67 MPa), while the solid composite polymer layers on both sides ensure adequate lithium‐ion transfer number (0.42), electrochemical and thermal safety stability. The Li//Li symmetric battery with optimized solid electrolyte can circulate steadily for more than 1800 h, especially at 80 °C. For further illustration, the solid‐state LiFePO4//Li cells provide ideal cyclic stability and rate capability, as well as extreme temperature endurance till 80 °C. Thus, this work provides an auspicious strategy to design a safe, high‐strength, high‐energy density battery for high‐temperature special needs. [ABSTRACT FROM AUTHOR]

In solid polymer electrolytes (SPEs) based Li–metal batteries, the inhomogeneous migration of dual‐ion in the cell results in large concentration polarization and reduces interfacial stability during cycling. A special molecular‐level designed polymer electrolyte (MDPE) is proposed by embedding a special functional group (4‐vinylbenzotrifluoride) in the polycarbonate base. In MDPE, the polymer matrix obtained by copolymerization of vinylidene carbonate and 4‐vinylbenzotrifluoride is coupled with the anion of lithium‐salt by hydrogen bonding and the "σ‐hole" effect of the CF bond. This intermolecular interaction limits the migration of the anion and increases the ionic transfer number of MDPE (tLi+ = 0.76). The mechanisms of the enhanced tLi+ of MDPE are profoundly understood by conducting first‐principles density functional theory calculation. Furthermore, MDPE has an electrochemical stability window (4.9 V) and excellent electrochemical stability with Li–metal due to the CO group and trifluoromethylbenzene (ph‐CF3) of the polymer matrix. Benefited from these merits, LiNi0.8Co0.1Mn0.1O2‐based solid‐state cells with the MDPE as both the electrolyte host and electrode binder exhibit good rate and cycling performance. This study demonstrates that polymer electrolytes designed at the molecular level can provide a broader platform for the high‐performance design needs of lithium batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • LL-GCE has high ionic conductivity and Li+ transference number. • LL-GCE possesses favorable anion-rich solvation structures. • LL-GCE generates LiF-rich CEI and SEI layers after cycling. • LL-GCE shows outstanding compatibility with both Li anode and high-voltage cathode. Ether-based polymer electrolyte shows promising potential for application in solid-state lithium batteries owing to its cost-effectiveness, excellent flexibility, and above all, remarkable stability to lithium metal anode. However, it still suffers from challenges related to low ionic conductivity and inferior oxidation resistance. Herein, an ether-based gel composite electrolyte containing Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) ceramics (LL-GCE) is fabricated via an in-situ polymerization method which can guarantee good interface contact with electrodes. The ceramics not only activate the interaction between polymers and lithium salts, resulting in significantly enhanced ionic conductivity (7.9 × 10−4 S cm−1), but also collaborate with poly(1,3-dioxolane) (PDOL) to construct favorable anion-rich solvation configurations, which effectively restrict the anion migration with Li+ transference number significantly increased to 0.83. Furthermore, the regulated solvation structures can passivate the electrode surface with a high content of robust LiF components formed on the electrolyte/electrode interphase. Consequently, the composite electrolyte demonstrates excellent abilities to inhibit Li dendrite growth and match with high-voltage cathodes. For instance, the LiFePO 4 ||Li cell using such electrolyte conveys a capacity of 135.4 mAh/g and the capacity retention is 99.3 % after 250 cycles at 1C. The LiCoO 2 ||Li full cell also shows excellent cycling performance. This work provides an effective strategy to modify ether-based polymer electrolytes and can boost their development in high-performance solid state lithium metal batteries. [ABSTRACT FROM AUTHOR]

• Solvent-free solid polymer electrolytes can be acquired with in-situ polymerized plastic crystal electrolytes; • The deformable property of plastic crystals and in-situ polymerization process promise low resistance; • As-developed electrolytes display excellent compatibility with lithium anode, enabling stable operation of symmetric Li cells over 2500 h under 0.5 mA cm−2; • Our developed solid-state lithium metal batteries exhibit high capacity retention (>90 %) over 900 cycles under 1.0 C at room temperature. Solid polymer electrolytes (SPEs) are regarded as the pivotal materials for next-generation battery technology on account of their improved safety and potentially enabling higher energy density chemistry compared to conventional liquid electrolytes. However, the practical application of SPEs still hindered by the limited room temperature ionic conductivity, insufficient physical contact and unstable solid electrolyte interface (SEI) with electrodes. Here we report a class of in-situ polymerized plastic crystal electrolytes (PPCEs) which break the trade-offs between degree of polymerization and ionic conductivity of in-situ polymerized SPEs. The complete polymerized electrolytes combined both the advantages of in-situ polymer electrolytes and plastic crystal electrolytes, exhibiting thin thickness, good ionic conductivity, outstanding electrochemical stability and low interfacial impedance. As a result, symmetric Li cells with PPCE showed a superior long lifespan over 2500 h under 0.5 mA cm−2 and Li/PPCE/LiFePO 4 (LiNi 0.8 Co 0.1 Mn 0.1 O 2) cells displayed excellent long-cycling performance under 1.0 C at room temperature. The in-situ polymerized electrolyte system provides an effective strategy for developing safe and high-energy solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

The development of solid-state electrolytes (SSEs) with high ionic conductivity, outstanding electrochemical window, and promising mechanical strength is a key factor in realizing the commercialization of high energy density solid-state lithium metal batteries (LMBs). Covalent organic frameworks (COFs) are a functional crystalline material with highly customizable molecular networks and one-dimensional channel structures, thus showing great potential applications in SSEs. Herein, we design flexible COF-poly(vinyl ethylene carbonate) (PVEC) (abbreviated as COF-PVEC) composite electrolyte films with excellent ionic conductivity and high mechanical strength, enabling dendrite-free and long-term running solid-state LMBs. Owing to the lithium-philic triazine and carbon-carbon double bonds groups in the COF skeleton, the obtained flexible COF-PVEC shows high ionic conductivity up to 1.11 × 10−4 S·cm−1 at 40 °C, and enlarged electrochemical window up to 4.6 V (vs. Li+/Li) compared with pure PVEC electrolyte. At the same time, the lithium dendrites are efficiently inhibited after discharge-charging cycles, due to the improved Young's modulus (150 MPa) and ordered channels of COF. Using the various features of COF-PVEC, we assembled a solid-state full battery with LiFePO4 cathode, which showed superior rate capacity (151.8, 146.2, 139.2, 128.1, 113.7, and 100.8 mAh·g−1 at 0.1, 0.2, 0.5, 1, 1.5, and 2 C, respectively) and excellent long-term cycling stability (over 400 cycles at 1 C). We believe that the COF-based composite electrolyte can become one of the most promising high-performance SSEs for solid-state LMBs. [ABSTRACT FROM AUTHOR]

Halide solid electrolytes (SEs) are attracting great attention, owing to their high ionic conductivity and excellent high-voltage compatibility. However, severe moisture sensitivity, poor thermal stability, and instability at the lithium metal anode interface with chloride and bromide SEs retard their applications in solid-state lithium metal batteries. Fluoride SEs are expected to solve these problems, but they are now plagued by inadequate room-temperature (RT) ionic conductivity. Herein, a low-temperature molten salt (LiCl+1.33AlCl 3 ) ablation method is proposed to enhance the ionic conductivity of monoclinic Li 3 GaF 6 by particle boundary doping. The RT ionic conductivity of Li 3 GaF 6 is correspondingly increased by 2 orders of magnitude, and the conductivity reaches 10 -4 S cm -1 at 60 °C. The improved ionic conductivity benefits from the enhancement of interfacial ion transport, with the formation of more conductive chlorine-doped Li 3 GaF 6- x Cl x and in situ binder LiAlCl 4 to cement surrounding nanoparticles. The as-synthesized Li 3 GaF 6 demonstrates outstanding humidity tolerance without conductivity degradation after exposure to a relative humidity of up to 35%. It also exhibits the widest electrochemical stability window experimentally (close to 6 V) compared with other state-of-the-art SEs. The solid-state Li/Li 3 GaF 6 /LiFePO 4 cell with a stable Li + -conductive polymer interface is successfully driven for at least 200 cycles at 0.5C. Our study provides a solution to various chemical and electrochemical stability issues encountered by the halide SE family.

Solid-state lithium metal batteries (SSLMBs) with solid polymer electrolyte (SPE) are highly promising for next-generation energy storage due to their enhanced safety and energy density. However, the stability of the solid electrolyte interphase (SEI) on the lithium metal/SPE interface is a major challenge, as continuous SEI degradation and regeneration during cycling lead to capacity fading. This article investigates the SEI formation on lithium anodes (l-SEI) and composite lithium anodes (c-SEI) in solid-state lithium metal batteries. The composite anodes form a uniform Li2S-rich inorganic SEI layer and a thinner organic SEI layer, effectively passivating the interface for enhanced cycling stability. Specifically, the full cells with c-SEI anodes sustain over 400 cycles at 0.5 C under a high areal capacity of 2.0 mAh cm-2. Moreover, the reversible high-loading solid-state pouch cells exhibit exceptional safety even after curling and cutting. These findings offer valuable insights into developing composite electrodes with robust SEI for solid-state polymer-based lithium metal batteries., (© 2024 Wiley‐VCH GmbH.)

In response to the critical challenges of interfacial impedance and volumetric changes in Li (1+x) Al x Ti (2‑x) (PO 4 ) 3 (LATP)-based lithium metal batteries, an elastomeric lithium-conducting interlayer fabricates from fluorinated hydrogenated nitrile butadiene rubber (F-HNBR) matrix is introduced herein. Owing to the vulcanization, vapor-phase fluorination, and plasticization processes, the lithium-conducting interlayer exhibits a high elasticity of 423%, exceptional fatigue resistance (10 000 compression cycles), superior ionic conductivity of 6.3 × 10 -4 S cm -1 , and favorable lithiophilicity, rendering it an ideal buffer layer. By integrating the F-HNBR interlayer, the LATP-based lithium symmetric cells demonstrate an extended cycle life of up to 1600 h at 0.1 mA cm -2 and can also endure deep charge/discharge cycles (0.5 mAh cm -2 ) for the same duration. Furthermore, the corresponding lithium metal full cells achieve 500 cycles at 0.5 C with 98.3% capacity retention and enable a high-mass-loading cathode of 11.1 mg cm -2 to operate at room temperature., (© 2024 Wiley‐VCH GmbH.)

A majority of flexible and wearable electronics require high operational voltage that is conventionally achieved by serial connection of battery unit cells using external wires. However, this inevitably decreases the energy density of the battery module and may cause additional safety hazards. Herein, a bipolar textile composite electrode (BTCE) that enables internal tandem-stacking configuration to yield high-voltage (6 to 12 V class) solid-state lithium metal batteries (SSLMBs) is reported. BTCE is comprised of a nickel-coated poly(ethylene terephthalate) fabric (NiPET) core layer, a cathode coated on one side of the NiPET, and a Li metal anode coated on the other side of the NiPET. Stacking BTCEs with solid-state electrolytes alternatively leads to the extension of output voltage and decreased usage of inert package materials, which in turn significantly boosts the energy density of the battery. More importantly, the BTCE-based SSLMB possesses remarkable capacity retention per cycle of over 99.98% over cycling. The composite structure of BTCE also enables outstanding flexibility; the battery keeps stable charge/discharge characteristics over thousands of bending and folding. BTCE shows great promise for future safe, high-energy-density, and flexible SSLMBs for a wide range of flexible and wearable electronics., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Composite polymer electrolytes (CPEs) are promising for the realization of solid‐state lithium metal batteries (SSLMBs) with high energy density and safety. However, CPEs suffer from insufficient ionic conductivity and low mechanical strength at thin films. Herein this study, a porously nanofibrous Li7La3Zr2O12 (LLZO)/polyacrylonitrile (PAN) substrate prepared by electrospinning is filled with polyethylene oxide (PEO)/lithium salt (LiTFSI) to form LLZO/PAN/PEO/LiTFSI (LPPL) CPEs. The robust LLZO/PAN nanofibrous membrane mechanically supports the soft PEO/LiTFSI, while the dispersed LLZO together with the PEO/LiTFSI forms a dual Li+ conductive pathway. Benefiting from the great synergies between the building blocks, the obtained LPPL CPEs possess a high tensile strength (8.2 MPa) with a thickness of only 20 μm, resulting in a good ionic conductivity. In addition, the LPPL CPEs also exhibit a wide electrochemical window (5.5 V), high thermal stability, and excellent stability with lithium metal. As a result, the LiFePO4 (LFP)/LPPL/Li SSLMBs show good rate capability and cycling stability (100.5 mA h g−1@1.0 C after 430 cycles) at 60 °C. In addition, the soft‐packaged LFP/LPPL/Li SSLMBs demonstrate high safety under destructive conditions such as bending and cutting. Moreover, the LPPL CPEs are also applicable to the SSLMBs with high‐energy LiNi0.8Co0.1Mn0.1O2 (NCM811) or high‐capacity sulfur cathodes.

Nowadays solid‐state lithium metal batteries (SSLMBs) catch researchers’ attention and are considered as the most promising energy storage devices for their high energy density and safety. However, compared to lithium‐ion batteries (LIBs), the low ionic conductivity in solid‐state electrolytes (SSEs) and poor interface contact between SSEs and electrodes counteract some advantages of SSEs. As a result, SSLMBs show high energy density but low critical current density and slow charging speed. Herein, the recent progress and proposed strategies for fast‐charging SSLMBs are reviewed. In the second part of this review, various strategies for improving SSE performance in fast‐charging batteries are comprehensively highlighted. In the third part, various rational structure design schemes benefitting fast‐charging batteries are discussed. Finally, the development of fast‐charging SSLMBs is concluded and prospected. It is believed that the combination of fast‐charging times and SSLMBs is rather competitive for next‐generation, high energy density, high safety, and high charging rate energy storage devices.

[Display omitted] • The conformation of SN molecules inversed by polymer brushes to alleviate the corrosion reactions of SN on Li anodes. • The interactions between polymer brushes and SN confirmed by theoretical calculations and experiments. • Polymer brushes regulate Li+ transport pathway with the inversed SN molecules to achieve uniform Li deposition. • The assembled solid-state Li||LiFePO 4 batteries exhibit a capacity of 115.0 mAh g−1 after 1500 cycles at 3 C. Solid-state lithium metal batteries are considered as the next-generation energy storage devices, but their application is significantly hindered by poor interfacial compatibility between Li anodes and solid-state electrolytes, especially for succinonitrile (SN) based electrolyte. Herein, this issue is addressed by a conformation inversion strategy via introducing a PE separator grafted with poly-(lithium 2-acrylamido-2-methylpropanesulfonic acid) (PAMPSLi) brushes into a SN-based electrolyte. The PAMPSLi brushes inverse the conformation of SN molecules through the multiple interactions between −SO 3 Li and cyanide groups, alleviating the corrosion reactions of SN on Li anodes. Significantly, the PAMPSLi brushes regulate Li+ transport pathway with the inversed SN molecules at the anode/electrolyte interface to achieve uniform Li deposition. Notably, the PAMPSLi brushes contribute to a solid electrolyte interphase (SEI) film rich in LiF and Li 3 N. Consequently, the solid-state Li||LiFePO 4 batteries with the resulting electrolyte exhibit a specific discharge capacity of 115.0 mAh/g and a considerably long cycle life of 1500 cycles at 3 C. A pouch cell with a high-loading LiFePO 4 cathode (18 mg cm−2) also exhibits a high areal capacity and superior safety. This study provides a novel strategy for achieving a stable electrolyte/anode interface in SN-based electrolytes, which facilitates the practical application of solid-state batteries with long life and high energy density. [ABSTRACT FROM AUTHOR]

Solid‐state lithium metal batteries (SLMBs) are attracting enormous attention due to their enhanced safety and high theoretical energy density. However, the alkali lithium with high reducibility can react with the solid‐state electrolytes resulting in the inferior cycle lifespan. Herein, inspired by the idea of interface design, the 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethanesulfonyl) imide as an initiator to generate an artificial protective layer in polymer electrolyte is selected. Time‐of‐flight secondary ion mass spectrometry and X‐ray photoelectron spectroscopy reveal the stable solid electrolyte interface (SEI) is in situ formed between the electrolyte/Li interface. Scanning electron microscopy (SEM) images demonstrate that the constructed SEI can promote homogeneous Li deposition. As a result, the Li/Li symmetrical cells enable stable cycle ultralong‐term for over 4500 h. Moreover, the as‐prepared LiFePO4/Li SLMBs exhibit an impressive ultra‐long cycle lifespan over 1300 cycles at 1 C, as well as 1600 cycles at 0.5 C with a capacity retention ratio over 80%. This work offers an effective strategy for the construction of the stable electrolyte/Li interface, paving the way for the rapid development of long lifespan SLMBs. [ABSTRACT FROM AUTHOR]

Abstract Solid‐state lithium metal batteries (SLMBs) are attracting enormous attention due to their enhanced safety and high theoretical energy density. However, the alkali lithium with high reducibility can react with the solid‐state electrolytes resulting in the inferior cycle lifespan. Herein, inspired by the idea of interface design, the 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethanesulfonyl) imide as an initiator to generate an artificial protective layer in polymer electrolyte is selected. Time‐of‐flight secondary ion mass spectrometry and X‐ray photoelectron spectroscopy reveal the stable solid electrolyte interface (SEI) is in situ formed between the electrolyte/Li interface. Scanning electron microscopy (SEM) images demonstrate that the constructed SEI can promote homogeneous Li deposition. As a result, the Li/Li symmetrical cells enable stable cycle ultralong‐term for over 4500 h. Moreover, the as‐prepared LiFePO4/Li SLMBs exhibit an impressive ultra‐long cycle lifespan over 1300 cycles at 1 C, as well as 1600 cycles at 0.5 C with a capacity retention ratio over 80%. This work offers an effective strategy for the construction of the stable electrolyte/Li interface, paving the way for the rapid development of long lifespan SLMBs.

Solid-state lithium metal batteries have attracted more and more attention in recent years because of their high safety and energy density, with developments in the new energy industry and energy storage industry. However, solid-state electrolytes are usually symmetric and are not compatible with the cathode and anode at once. In this work, a flexible asymmetric organic-inorganic composite solid-state electrolyte consisting of PI membrane, succinonitrile (SN), LiLaZrTaO(LLZTO), Poly (ethylene glycol) (PEO), and LiTFSI were prepared by solution casting successfully. This lightweight solid electrolyte is stable at a high temperature of 150°C and exhibits a wide electrochemical window of more than 6 V. Furthermore, the high ionic conductivity of the flexible solid electrolyte was 7.3 × 10−7 S/cm. The solid-state batteries assembled with this flexible asymmetric organic-inorganic composite solid electrolyte exhibit excellent performance at ambient temperature. The specific discharge capacity of coin cells using asymmetric organic-inorganic composite solid-state electrolytes was 156.56 mAh/g, 147.25 mAh/g, and 66.55 mAh/g at 0.1, 0.2, and 1C at room temperature. After 100 cycles at 0.2C, the reversible discharging capacity was 96.01 mAh/g, and Coulombic efficiency was 98%. Considering the good performance mentioned above, our designed flexible asymmetric organic-inorganic composite solid electrolyte is appropriate for next-generation solid-state batteries with high cycling stability.

The polymer electrolyte with superior properties and intimate interface contact with stability and compatibility between electrolyte and electrodes are essential for the high energy density solid-state lithium metal batteries. In this review, we present an overview of research progress on polymer electrolytes, the interface issues and remedy strategies for stabilizing the interface contact. Then we provide the guidance for the development of high-performance solid-state lithium metal batteries through designing polymer electrolyte by functional unit adjustments and improving the interface contact by effective strategies and in-situ polymerization process. [Display omitted] The polymer electrolyte based solid-state lithium metal batteries are the promising candidate for the high-energy electrochemical energy storage with high safety and stability. Moreover, the intrinsic properties of polymer electrolytes and interface contact between electrolyte and electrodes have played critical roles for determining the comprehensive performances of solid-state lithium metal batteries. In this review, the development of polymer electrolytes with the design strategies by functional units adjustments are firstly discussed. Then the interfaces between polymer electrolyte and cathode/anode, including the interface issues, remedy strategies for stabilizing the interface contact and reducing resistances, and the in-situ polymerization method for enhancing the compatibilities and assembling the batteries with favorable performances, have been introduced. Lastly, the perspectives on developing polymer electrolytes by functional units adjustment, and improving interface contact and stability by effective strategies for solid-state lithium metal batteries have been provided. [ABSTRACT FROM AUTHOR]

Traditional PEO electrolyte has high crystallinity which hinders the transmission of Li + , resulting in poor ion conductivity and complicated processing technology. Herein, a polymer electrolyte (p-electrolyte) with a wide electrochemical window and high ionic conductivity is designed, which possesses an amorphous condensed structure. The amorphous structure provides fast transport channels for Li + , so the p-electrolyte possesses an electrochemical window of 4.2 V, and high ionic conductivity of 1.58 × 10 -5  S cm -1 at room temperature, which is 1-2 orders of magnitude higher than that of traditional PEO electrolyte. By using the designed polymer electrolyte as the foundation, an in situ curable composite polymer electrolyte (CPE-L) with multiple Li + transport channels is elaborately constructed. The Cu-BTC MOF stores abundant Li + , which is introduced into the p-electrolyte. The rich unsaturated Cu 2+ coordination sites of Cu-BTC can anchor TFSI - to release Li + , and the pore structure of Cu-BTC MOF cooperates with LLZTO nanoparticles to provide multiple fast transport channel for Li + , resulting in remarkable ionic conductivity (1.02 × 10 -3  S cm -1 ) and Li + transference number (0.58). The Li||CPE-L||Li symmetric battery cycles stably for more than 700 h at 0.1 mA cm -2 , while the specific capacity of full battery is ≈153 mAh g -1 (RT, 0.2 C)., (© 2024 Wiley‐VCH GmbH.)

Solid polymer electrolytes (SPEs) represent a pivotal advance toward high-energy solid-state lithium metal batteries. However, inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Recent efforts have focused on transforming liquid/solid interfaces into solid/solid ones through in situ polymerization, which shows potential especially in reducing interface impedance. Here, we designed high-voltage SSLMBs with dual-reinforced stable interfaces by combining interface modification with an in situ polymerization technology inspired by targeted effects in medicine. Theoretical calculations and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis demonstrate that tetramethylene sulfone (TMS) and bis(2,2,2-trifluoromethyl) carbonate (TFEC) exhibit selective adsorption at the interface of the LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) cathode and Li anode, respectively. These compounds further decompose to form a stable cathode-electrolyte interface (CEI) film and a solid electrolyte interface (SEI) film, thereby simultaneously achieving a superior interface between the SPE and both the Li anode and NCM cathode. The developed Li||SPE||Li cell sustained cycling for more than 1000 h at 0.3 mA cm -2 , and the NCM||SPE||Li cell also demonstrated an excellent capacity retention of 86.8% after 1000 cycles at 1 °C. This work will provide valuable insights for the rational design of high-voltage SSLMBs with stable interfaces, leveraging in situ polymerization as a cornerstone technology.

The emergence of solid-state battery technology presents a potential solution to the dissolution challenges of high-capacity small molecule quinone redox systems. Nonetheless, the successful integration of argyrodite-type Li 6 PS 5 Cl, the most promising solid-state electrolyte system, and quinone redox systems remains elusive due to their inherent reactivity. Here, a library of quinone derivatives is selected as model electrode materials to ascertain the critical descriptors governing the (electro)chemical compatibility and subsequently the performances of Li 6 PS 5 Cl-based solid-state organic lithium metal batteries (LMBs). Compatibility is attained if the lowest unoccupied molecular orbital level of the quinone derivative is sufficiently higher than the highest occupied molecular orbital level of Li 6 PS 5 Cl. The energy difference is demonstrated to be critical in ensuring chemical compatibility during composite electrode preparation and enable high-efficiency operation of solid-state organic LMBs. Considering these findings, a general principle is proposed for the selection of quinone derivatives to be integrated with Li 6 PS 5 Cl, and two solid-state organic LMBs, based on 2,5-diamino-1,4-benzoquinone and 2,3,5,6-tetraamino-1,4-benzoquinone, are successfully developed and tested for the first time. Validating critical factors for the design of organic battery electrode materials is expected to pave the way for advancing the development of high-efficiency and long cycle life solid-state organic batteries based on sulfides electrolytes., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Solid-state lithium metal batteries (SSLMBs) are a promising energy storage technology, but challenges persist including electrolyte thickness and lithium (Li) dendrite puncture. A novel three-dimensional "peapod-like" composite solid electrolyte (CSEs) with low thickness (26.8 μm), high mechanical strength, and dendrite inhibition was designed. Incorporating Li 7 La 3 Zr 2 O 12 (LLZO) enhances both mechanical strength and ionic conductivity, stabilizing the CSE/Li interface and enabling Li symmetric batteries to stabilize for 3000 h. With structural advantages, the assembled LFP||Li and NCM811||Li cells exhibit excellent cycling performance. In addition, the constructed NCM811 pouch cell achieves a high gravimetric/volumetric energy density of 307.0 Wh kg -1 /677.7 Wh L -1 , which can light up LEDs under extreme conditions, demonstrating practicality and high safety. This work offers a generalized strategy for CSE design and insights into high-performance SSLMBs.

Ultrathin composite electrolytes hold great promise for high energy density solid-state lithium metal batteries (SSLMBs). However, finding an electrolyte that can simultaneously balance the interfacial stability of the lithium anode and high-voltage cathode is challenging. The present study utilized the both-side tape casting technique to fabricate ultrathin asymmetric composite electrolytes reinforced with polyimide (PI) fiber membrane, with a thickness of 26.8 μm. The implementation of this asymmetric structural design enables SSLMBs to attain favorable interfacial characteristics, such as exceptional resistance to lithium dendrite puncture and compatibility with high voltages. The suppression of lithium dendrite growth and the extension of the cycle life of lithium symmetric batteries by 4000 h are both experimental and theoretically demonstrated under the dual confinement of PI fiber membrane and Li 7 La 3 Zr 2 O 12 ceramic fibers. Furthermore, the integration of multicomponent solid electrolyte interphase and cathode electrolyte interface interfacial layers into the lithium anode and high-voltage cathode enhance theirs cycling stability. With a gravimetric/volumetric energy density of 333.1 Wh kg -1 /713.2 Wh L -1 , the assembled LiNi 0.8 Co 0.1 Mn 0.1 O 2 pouch cell demonstrates exceptional safety. The extensive application of this design concept to SSLMBs enables the resolution of electrode/electrolyte interface issues.

Severe interfacial side reactions of polymer electrolyte with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and Li metal anode restrict the cycling performance of solid‐state NCM811/Li batteries. Herein, we propose a chemically stable ceramic‐polymer‐anchored solvent composite electrolyte with high ionic conductivity of 6.0×10−4 S cm−1, which enables the solid‐state NCM811/Li batteries to cycle 1500 times. The Li1.4Al0.4Ti1.6(PO4)3 nanowires (LNs) can tightly anchor the essential N, N‐dimethylformamide (DMF) in poly(vinylidene fluoride) (PVDF), greatly enhancing its electrochemical stability and suppressing the side reactions. We identify the ceramic‐polymer‐liquid multiple ion transport mechanism of the LNs‐PVDF‐DMF composite electrolyte by tracking the 6Li and 7Li substitution behavior via solid‐state NMR. The stable interface chemistry and efficient ion transport of LNs‐PVDF‐DMF contribute to superior performances of the solid‐state batteries at wide temperature range of −20–60 °C. [ABSTRACT FROM AUTHOR]

Solid-state lithium metal batteries (SSLBs) contain various kinds of interfaces, among which the solid electrode|solid electrolyte (ED|SE) interface plays a decisive role in the battery's power density and cycling stability. However, it is still lack of comprehensive knowledge and understanding about various interfacial physical/chemical processes so far. Although tremendous efforts have been dedicated to investigate the origin of large interfacial resistance and sluggish charge (electron/ion) transfer process, many scientific and technological challenges still remain to be clarified. In this review, we detach and discuss the critical individual challenge, including charge transfer process, chemical and electrochemical instability, space charge layers, physical contact and mechanical instability. The fundamental concepts, individual effects on the charge transfer and potential solutions are summarized based on material's thermodynamics, electrode kinetics and mechanical effects. It is anticipated that future research should focus on quantitative analysis, modeling analysis and in-situ microstructure characterizations in order to obtain an efficient manipulation about the complex interfacial behaviors in all solid-state Li batteries. [ABSTRACT FROM AUTHOR]

Composite solid-state electrolyte have good interfacial compatibility and mechanical properties, but their safety (such as easy to catch fire) and economic cost are still problems. In present work, an composite solid-state electrolyte was prepared by inserting poly(vinylidene fluoride)-based polymer electrolyte matrix into the interlayer of a low cost clay mineral-montmorillonite. The composite electrolyte exhibited remarkable characteristics, including excellent flame retardancy, high room temperature ionic conductivity of 2.28 × 10−4 S cm−1, wide electrochemical stability window of 4.8 V, high lithium-ion transference number of 0.57 and good mechanical strength of 12.58 MPa. Furthermore, LiFePO 4 -based solid-state battery, utilizing this composite solid-state electrolyte, exhibited stable cycling with discharge specific capacity of 130 mAh g−1 for over 100 cycles at a rate of 0.5C at room temperature. This successful performance demonstrated the potential of utilizing low-cost and environmentally friendly raw clay mineral materials in high energy density solid-state battery applications. • A montmorillonite-based composite solid-state electrolyte was prepared. • The composite electrolyte exhibited high ionic conductivity at room temperature. • The excellent flame retardancy was attributed to the high montmorillonite content. • Low-cost clay mineral greatly reduced the cost of solid electrolytes. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes are one of the candidates for solid electrolytes to solve safety issues and improve the energy density of solid-state lithium batteries. Gel polymer electrolyte has high ionic conductivity at room temperature (~ 10−3 S cm−1), but its mechanical properties are poor. Herein, we prepared a series of composite gel polymer electrolytes by N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, poly(vinylidene fluoride-hexafluoropropylene), LiTFSI, and various inorganic fillers. The addition of 5 wt% TiO2 can not only increase the ionic conductivity of gel polymer electrolytes but also improve the mechanical properties of gel polymer electrolytes. Besides, as a semiconductor, the TiO2 has safety risk when uses in composite gel polymer electrolyte. TiO2-ILGPE safety is investigated by cyclic voltammetry and battery performance. Additionally, TiO2-ILGPE displays a perfect flame-retarding ability, and TiO2 would not be reduced by the lithium metal anode. [ABSTRACT FROM AUTHOR]