Li Symmetric Cells Research Articles

Strategic Atomic Interaction Modification for Highly Durable Inorganic Solid Electrolytes in Advanced All‐Solid‐State Li‐Metal Batteries

All‐solid‐state Li‐metal battery (ASSLB) represents advantageous energy storage system for automotive applications. For ASSLB, inorganic solid electrolyte is essential in determining safety and cycling performance. However, significant challenges persist in practical construction of ASSLB with optimized electrolyte. Specifically, electrolyte's structural instability influencing its electrochemical performance remains critical issue within typical operating temperatures for ASSLB in electric vehicles. Herein, this challenge is fundamentally addressed by substituting trace amount of lithium with cadmium, which lacks crystal field stabilization energy. This strategy of atomic interaction modification has induced electrolyte's structural distortion and electronic alteration by deliberately introducing disorder at local lithium sites. Li symmetric cell with cadmium‐substituted antiperovskite solid electrolyte exhibits outstanding critical current density of 11.5 mA cm−2 (5.75 mAh cm−2) and excellent stability for 3000 h at 10.0 mA cm−2 (5.0 mAh cm−2). This study highlights explicit research direction for breakthrough of ASSLB, focusing on understanding how local distortion affects complex inorganic materials.

Optimization Design of Fluoro-Cyanogen Copolymer Electrolyte to Achieve 4.7V High-Voltage Solid Lithium Metal Battery.

Raising the charging voltage and employing high-capacity cathodes like lithium cobalt oxide (LCO) are efficient strategies to expand battery capacity. High voltage, however, will reveal major issues such as the electrolyte's low interface stability and weak electrochemical stability. Designing high-performance solid electrolytes from the standpoint of substance genetic engineering design is consequently vital. In this instance, stable SEI and CEI interface layers are constructed, and a 4.7V high-voltage solid copolymer electrolyte (PAFP) with a fluoro-cyanogen group is generated by polymer molecular engineering. As a result, PAFP has an exceptionally broad electrochemical window (5.5V), a high Li+ transference number (0.71), and an ultrahigh ionic conductivity (1.2 mS cm-2) at 25°C. Furthermore, the Li||Li symmetric cell possesses excellent interface stability and 2000 stable cycles at 1mA cm-2. The LCO|PAFP|Li batteries have a 73.7% retention capacity after 1200 cycles. Moreover, it still has excellent cycling stability at a high charging voltage of 4.7V. These characteristics above also allow PAFP to run stably at high loading, showing excellent electrochemical stability. Furthermore, the proposed PAFP provides new insights into high-voltage resistant solid polymer electrolytes.

Localized high concentration polymer electrolyte enabling room temperature solid-state lithium metal batteries with stable LiF-rich interphases

Polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) based polymer electrolyte shows mechanical flexibility, soft and intimidate physical contact and good electrochemical stability, however, low ionic conductivity at room temperature and unstable interphases against Li metal hinder its application. In this article, we propose a universal strategy to prepare localized high concentration polymer electrolytes (LHCPE) in which high concentration lithium salt (LiTFSI) dissolved in tiny residual solvent (DMF) and the PVDF-HFP serves as solid dilution. The LHCPE regulates the solvation structure of lithium ions with anions instead of DMF solvent, allowing more anions to coordinate with Li+ and forming amount contact ion pairs (CIPs) and aggregates (AGGs). As a result, high ionic conductivity (5.9 × 10−4 S cm−1) and low activation energy (0.10 eV) achieved. The LHCPE also induces the decomposition of anions-derived LiF-rich interphases, that is ionic conducive and mechanical robust, thereby greatly improving the charge transfer kinetics and stability towards Li metal anodes. Consequently, at 0.5 mA cm−2 and 0.25 mAh cm−2, stable and long-term cycling over 2000 h obtained under room temperature in Li//Li symmetric cells achieved. The full solid-state LFP//LHCPE//Li cells further exhibit excellent capacity retention of 82.83 % even after 1200 cycles at room temperature and a high rate of 8 C (1C=170 mA·g−1). Our work shed light on the design of high-performance polymer-based composite electrolytes by manipulating the Li solvation structure.

Boosted Li+ transport ensured by high-entropy Prussian blue analogues with tuned PF6− adsorption for stable Li metal anode

The inhomogeneous lithium metal (Li) deposition and low lithium ion (Li+) mobility lead to the formation and growth of Li dendrites, which impede the desirable performance of Li metal batteries (LMBs) with high energy density in widely practical applications. Herein, a high-entropy MnCoNiCuZn-Prussian blue analogue (HE-PBA) is utilized to modify the commercial polypropylene separator (PP@HE-PBA), which will form an artificial protective layer on the surface of Li. The polar –CN groups of HE-PBA can enhance the wettability of PP to the electrolyte, while the movement of PF6− anions are flexibly tuned by the appropriate absorption ability and synergistic effect of multiple metal ions in HE-PBA. A high Li+ transference number of 0.69 is achieved, which can relieve the Li+ concentration polarization, regulate the Li+ flow, and realize the uniform Li deposition. With PP@HE-PBA, the Li||Li symmetric cells display durability up to 600 h in the ester-based electrolyte at 1 mA cm−2 for 1 mAh cm−2. Also, the PP@HE-PBA exhibits great potential in LMBs, where the Li4Ti5O12 (LTO) ||Li and sulfated polyacrylonitrile (S-PAN) ||Li batteries deliver superior cycling performance to those without PP@HE-PBA.

MgNiO2 as a Ceramic Additive To Improve the Durability of Lithium Metal Anode.

Ceramic materials are the most popular additives to regulate the reinless interfacial reaction between lithium and the electrolyte by strengthening the SEI layer or tuning lithium deposition. Here, we propose an exceptional material, MgNiO2, abbreviated as MN, which can improve the durability of lithium metal anode. Since it is undecomposed up to 0 V vs Li/Li+, the MN's particles give some semiconductive characteristics to the SEI layer to tune the interfacial reactions. The addition of MgNiO2 in the protective films lowers interfacial resistance, which is responsible for the improved durability of Li|Cu cells: ∼210 cycles, which is 4 times longer than that of the control. Furthermore, this ceramic is used to modify the carbon film woven with carbon nanofibers (CNF @ MN). The cells with this modified 3-D host present excellent operational lives, as high as ∼2400 h in Li|Li symmetric cells and ∼280 cycles in the Li|NCM811 cells. Our approaches demonstrate that MN is an effective ceramic for stabilizing the lithium anode. It also indicates that the inert nature of the semiconductor to lithium is worth exploring thoroughly.

A novel polymeric lithicone coating for superior lithium metal anodes

Lithium metal (Li) is commonly regarded as the “holy grail” of rechargeable batteries and can serve as anodes for constituting various high-energy lithium metal batteries (LMBs). However, it suffers from two notorious issues: (1) continuous formation of inhomogeneous solid electrolyte interphase and (2) Li dendritic growth. In this study, we developed a novel polymeric lithicone via a new molecular layer deposition (MLD) process, using lithium tert-butoxide (LTB) and hydroquinone (HQ) as precursors. We revealed that such an MLD process enabled the resultant LiHQ to grow linearly in a highly controllable and cyclic mode at a growth rate of 4 Å cycle−1. Furthermore, its low process deposition temperature of 150 °C made it possible to practice high-quality coatings over Li anodes directly. We demonstrated that, very compellingly, this LiHQ coating could protect Li anodes from corrosion and dendritic growth. As a consequence, this LiHQ coating has enabled Li||Li symmetric cells an extremely long cyclability up to 8000 Li-plating/stripping cycles without failure. More excitingly, we demonstrated that, coupled with LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes, the LiHQ-modified Li anodes could help the resultant Li||NMC811 realize a much better capacity retention and much longer cyclability. Thus, this study represents a strategic route for developing commercializeable LMBs.

Novel PEO-based Solid Polymer Electrolyte with High Elasticity and High Ionic Conductivity for Room Temperature Lithium Metal Batteries

The development and application of polyethylene oxide (PEO) based solid polymer electrolyte (SPE) is severely constrained by its low ionic conductivity and poor tensile resistance. To improve the electrochemical performance of SPE without losing its mechanical properties, a benzene sulfonate-based additive is adopted into crosslinking system composed of -CH2-CH2-O- segments to obtain a membrane with a high ionic conductivity of 1.47 × 10−4 S cm−1 and an ionic transference number of 0.70 at room temperature. The activation energy value of 0.128 eV gives evidence for a favorable migration mechanism of PTH-SPE. Anti-dendrite growth and contact optimization can be realized by molecular structure design with a tensile elongation of 490%. The reversible overpotential of Li||Li symmetric cell within 1000 h demonstrates that the compact PTH-SPE can inhibit the growth of lithium dendrite. This work provides a new strategy for designing high-performance solid electrolytes for room temperature via a green solvent-free method.

In Situ Fabrication of High Ionic and Electronic Conductivity Interlayers Enabling Long-Life Garnet-Based Solid-State Lithium Batteries.

Garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) is a promising solid-state electrolyte (SSE) because of its fast ionic conduction and notable chemical/electrochemical stability toward the lithium (Li) metal. However, poor interface wettability and large interface resistance between LLZTO and Li anode greatly restrict its practical applications. In this work, we develop an in situ chemical conversion strategy to construct a highly conductive Li2S@C layer on the surface of LLZTO, enabling improved interfacial wettability between LLZTO and the Li anode. The Li/Li2S@C-LLZTO-Li2S@C/Li symmetric cell has a low interface impedance of 78.5 Ω cm2, much lower than the 970 Ω cm2 of a Li/LLZTO/Li cell. Moreover, the Li/Li2S@C-LLZTO-Li2S@C/Li cell exhibits a high critical current density of 1.4 mA cm-2 and an ultralong stability of 3000 h at 0.1 mA cm-2. When used in a LiFePO4 battery, the Li/Li2S@C-LLZTO/LiFePO4 battery exhibits a high initial discharge capacity of 150.8 mA h g-1 at 0.2 C without lithium storage capacity attenuation during 200 cycles. This work provides a novel and feasible strategy to address interface issues of SSEs and achieve lithium-dendrite-free solid-state batteries.

Designing the Interface Layer of Solid Electrolytes for All-Solid-State Lithium Batteries.

Li1.3Al0.3Ti1.7(PO4)3 (LATP) is one of the most attractive solid-state electrolytes (SSEs) for application in all-solid-state lithium batteries (ASSLBs) due to its advantages of high ionic conductivity, air stability and low cost. However, the poor interfacial contact and slow Li-ion migration have greatly limited its practical application. Herein, a composite ion-conducting layer is designed at the Li/LATP interface, which a MoS2 film is constructed on LATP via chemical vapor deposition, followed by the introduction of a solid polymer (SP) liquid precursor to form a MoS2@SP protective layer. This protective layer not only achieves a lower Li-ion migration energy barrier, but also adsorbs more Li-ion, which is able to promote interfacial ion transport and improve interfacial contacts. Thanks to the improved migration and adsorption of Li-ion, the Li symmetric cell containing LATP-MoS2@SP exhibits a stable cycle of more than 1200h at 0.1mAcm-2. More remarkably, the capacity retention of the full cell assembled with LiFePO4 cathode is as high as 86.2% after 400 cycles at 1C. This work provides a design strategy for significantly improving unstable interfaces of SSEs and realizing high-performance ASSLBs.

Redox-active polypyrrole/bacterial cellulose bilayer separator for lithium-ion batteries

Separator is one of the important elements of lithium-ion batteries, which affects both the capacity and safety performance of the batteries. In this paper, polypyrrole (PPy) was grown on bacterial cellulose (BC) nanofibers using in situ polymerization. A bilayered composite separator with PPy-coated BC conductive upper layer and BC insulating lower layer was prepared by paper-making method. The redox-active PPy could contribute to a specific discharge capacity of 119 mAh g−1 at 2C current density for the battery with the bilayered separator, which is significantly superior to the device with the polyolefin separator (73 mAh g−1). Moreover, the redox layer provided a low overpotential in the Li//Li symmetric cell cycle, which played an important role for the cycle stability of the lithium-ion batteries.

Interfacial modulation of bifunctional electrolyte additive engineering for dendrite-free and robust lithium metal anode

Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential. Unfortunately, safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries. In this study, methyl vinyl sulfone (MVS), a sulfone-based functional electrolyte additive, is used in an additive engineering strategy to control Li-electrolyte interactions and address the aforementioned problems. Li dendrite growth may be restricted, and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer. The electrochemical performance of an ethylene carbonate/dimethyl carbonate (EC/DMC) + 1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability, maintaining a low overvoltage for over 750 h at 1 mA cm−2, and capacity of 1 mA h cm−2. Additionally, LiNi0.8Co0.1Mn0.1O2 (NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g−1. This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.

Surface Coating Enabling Sulfide Solid Electrolytes with Excellent Air Stability and Lithium Compatibility

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.

Polycarbonate-based composite polymer electrolytes with Al2O3 enhanced by in situ polymerized electrolyte Interlayers for all-solid-state lithium-metal batteries

Lithium-metal batteries (LMBs) have attracted significant attention as promising energy storage devices due to their high energy density. However, the practical application of LMBs is hindered by issues such as dendrite growth and electrolyte decomposition, which lead to poor cycling stability. To address these challenges, this study focuses on investigating the performance of poly(ethylene carbonate) (PEC)-based composite polymer electrolytes (CPEs) with an in situ polymerized poly(vinyl ethylene carbonate) (PVEC)-based electrolyte interlayer. The electrolytes were optimized by incorporating lithium bis(fluorosulfonyl)imide (LiFSI) salt, lithium bis(oxalato)borate (LiBOB) and lithium nitrate (LiNO3) additives, as well as Al2O3 filler. The objective was to improve the compatibility and cycling stability of LMBs by enhancing the electrolyte/electrode interfacial properties. Remarkably, the Li||Li symmetric cell utilizing the optimized CPE exhibited outstanding stability, operating for 700 h without short-circuiting at 0.1 mA cm−2, indicating excellent interfacial compatibility. Additionally, the Li||LiFePO4(LFP) cells using the same electrolyte demonstrated impressive performance, delivering initial discharge capacity of 159.32 mAh g−1 at 0.1 C with retention and coulombic efficiency close to 100 % after 100 cycles at 60 °C. This paper highlights the effectiveness of utilizing polymer electrolyte interlayers and additives like LiNO3 in CPEs to enhance the interfacial compatibility and cycling stability of LMBs.

Inhibiting Residual Solvent Induced Side Reactions in Vinylidene Fluoride-Based Polymer Electrolytes Enables Ultra-Stable Solid-State Lithium Metal Batteries.

Residual solvents in vinylidene fluoride (VDF)-based solid polymer electrolytes (SPEs) have been recognized as responsible for their high ionic conductivity. However, side reactions by the residual solvents with the lithium (Li) metal induce poor stability, which has been long neglected. This study proposes a strategy to achieve a delicate equilibrium between ion conduction and electrode stability for VDF-based SPEs. Specifically, 2,2,2-trifluoro-N,N-dimethylacetamide (FDMA) is developed as the nonside reaction solvent for poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF)-based SPEs, achieving both high ionic conductivity and significantly improved electrochemical stability. The developed FDMA solvent fosters the formation of a stable solid electrolyte interphase (SEI) through interface reactions with Li metal, effectively mitigating side reactions and dendrite growth on the Li metal electrode. Consequently, the Li||Li symmetric cells and Li||LiFePO4 cells demonstrate excellent cycling performance, even under limited Li (20µm thick) supply and high-loading cathodes (>10mg cm-2, capacity >1 mAh cm-2) conditions. The stable Li||LiCoO2 cells operation with a cutoff voltage of 4.48V indicates the high-voltage stability of the developed SPE. This study offers valuable insights into the development of advanced VDF-based SPEs for enhanced lithium metal battery performance and longevity.

Multiple uniform lithium-ion transport channels in Li6.4La3Zr1.4Ta0.6O12/Ce(OH)3 modified polypropylene composite separator for high-performance lithium metal batteries

Lithium (Li) metal anodes (LMAs) are regarded as leading technology for advanced-generation batteries due to their high theoretical capacity and favorable redox potential. However, the practical integration of LMAs into high-energy rechargeable batteries is hindered by the challenge of Li dendrite growth. In this work, nanoparticles of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) loaded with Ce(OH)3 (LLZTCO) were designed and synthesized by a hydrothermal method. A functional composite separator was crafted by coating one side of a polypropylene (PP) separator with a composite electrolyte comprised of polyvinylidene fluoride (PVDF) and LLZTCO. The synergistic interactions between PVDF and LLZTCO provide numerous rapid lithium-ion (Li+) channels, facilitating the efficient redistribution of disparate Li+ flux originating from the insulated PP separator. The composite separator demonstrated an ionic conductivity (σ) of 3.68 × 10–3 S cm−1, substantial Li+ transference number (t+) of 0.73, and a high electrochemical window of 4.8 V at 25℃. Furthermore, the Li/LLZTCO@PP/Li symmetric cells demonstrated stable cycling for over 2000 h without significant dendrite formation. The Li/LiFePO4 (LFP) cells assembled with LLZTCO@PP separators exhibited a capacity retention of 91.6 % after 400 cycles at 1C. This study offers a practical approach to fabricating composite separators with enhanced safety and superior electrochemical performance.

A Large-Scale Fabrication of Flexible, Ultrathin, and Robust Solid Electrolyte for Solid-State Lithium-Sulfur Batteries.

All-solid-state lithium metal batteries (ASSLMBs) are considered as the most promising candidates for the next-generation high-safety batteries. To achieve high energy density in ASSLMBs, it is essential that the solid-state electrolytes (SSEs) are lightweight, thin, and possess superior electrochemical stability. In this study, a feasible and scalable fabrication approach to construct 3D supporting skeleton using an electro-blown spinning technique is proposed. This skeleton not only enhances the mechanical strength but also hinders the migration of Li-salt anions, improving the lithium-ion transference number of the SSE. This provides a homogeneous distribution of Li-ion flux and local current density, promoting uniform Li deposition. As a result, based on the mechanically robust and thin SSEs, the Li symmetric cells show outstanding Li plating/stripping reversibility. Besides, a stableinterfacecontact between SSE and Li anode has been established with the formation of an F-enriched solid electrolyte interface layer. The solid-state Li|sulfurized polyacrylonitrile (Li|SPAN) cell achieves a capacity retention ratio of 94.0% after 350 cycles at 0.5 C. Also, the high-voltage Li|LCO cell shows a capacity retention of 92.4% at 0.5 C after 500 cycles. This fabrication approach for SSEs is applicable for commercially large-scale production and application in high-energy-density and high-safety ASSLMBs.

Highly Stretchable Polyurethane Porous Membranes with Adjustable Morphology for Advanced Lithium Metal Batteries.

A highly flexible, tunable morphology membrane with excellent thermal stability and ionic conductivity can endow lithium metal batteries with high power density and reduced dendrite growth. Herein, a porous Polyurethane (PU) membrane with an adjustable morphology was prepared by a simple nonsolvent-induced phase separation technique. The precise control of the final morphology of PU membranes can be achieved through appropriate selection of a nonsolvent, resulting a range of pore structures that vary from finger-like voids to sponge-like pores. The implementation of combinatorial DFT and experimental analysis has revealed that spongy PU porous membranes, especially PU-EtOH, show superior electrolyte wettability (472%), high porosity (75%), good mechanical flexibility, robust thermal dimensional stability (above 170 °C), and elevated ionic conductivity (1.38 mS cm-1) in comparison to the polypropylene (PP) separator. The use of PU-EtOH in Li//Li symmetric cell results in a prolonged lifespan of 800 h, surpasing the longevity of PU or PP cells. Moreover, when subjected to a high rate of 5 C, the LiFePO4/Li half-cell with a PU-EtOH porous membrane displayed better cycling performance (115.4 mAh g-1) compared to the PP separator (104.4 mAh g-1). Finally, the prepared PU porous membrane exhibits significant potential for improving the efficiency and safety of LMBs.

Ga-polymer dual interfacial layer modified Li metal for high-energy Li metal batteries

Lithium metal is regarded as the ultimate anode material for its extremely exceptional theoretical capacity and low reduction potential. Unfortunately, its practical utility has been constrained by changings such as the formation of lithium dendrites, volume expansion resulting from host-free structure, and uncontrollable side reactions with electrolyte. To achieve long cycle life, conventional single artificial layer strategy fails to solve due to ununiform lithium deposition problem. Consequently, the adoption of dual interfacial layer on lithium metal has emerged as prevailing strategy. In this study, we present a design of dual interface protective layer that combines a Ga-based liquid metal with the organic polymer Poly (ethylene glycol) diacrylate (PEGDA). This innovative combination offers synergistic benefits, including alleviate the volume effect and suppressing undesired interface side reactions. In practical test, the Li || Li symmetrical cell assembled from PEGDA Li-Ga dual interfacial layer maintains a low overpotential of 36.8 mV after 1400 h (2 mA cm−2, 2mAh cm−2). Moreover, even at a high rate of 5C, Li || LiNi0.8Co0.1Mn0.1O2 (NCM811, 1.0 mAh cm−2) cell still delivers a discharge capacity of 120 mAh g1, 1.4 times higher than bare Li. Notably, when integrated into a pouch cell with a LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode (1.52 mAh cm−2), this dual interface layers ensures stable performance over 60 cycles, with a capacity retention of 82 %. In summary, this innovative dual interface layer design offers a promising approach to address the intricate challenges associated with lithium metal protection and interface modification.

Reasonable design a high-entropy garnet-type solid electrolyte for all-solid-state lithium batteries

Traditional garnet solid electrolyte (Li7La3Zr2O12) suffers from low room temperature ionic conductivity, poor air stability, high sintering temperature and energy consumption. Considering the development prospects of high-entropy materials with high structural disorder and strong component controllability in the field of electrochemical energy storage, herein, a novel high-entropy garnet-type oxide solid electrolyte, Li5.75Ga0.25La3Zr0.5Ti0.5Sn0.5Nb0.5O12 (LGLZTSNO) was constructed by partially replacing the Li and Zr sites in Li7La3Zr2O12 with Ga and Ti/Sn/Nb elements, respectively. The experimental and density functional theory (DFT) calculation results show that the high-entropy LGLZTSNO electrolyte has preferable room temperature ion conductivity, air stability, interface contact performance with lithium anode, and the ability to suppress lithium dendrites. Thanks to the improvement of electrolyte performance, the critical current density of Li/Ag@LGLZTSNO/Li symmetric cell was increased from 0.42 to 1.57 mA cm−2, and the interface area specific impedance (IASR) was reduced from 765.2 to 42.3 Ω cm2. Meanwhile, the Li/Ag@LGLZTSNO/LFP full cell also exhibits excellent rate performance and cycling performance (148 mA h g−1 at 0.1 C and 124 mA h g−1 at 0.5 C, capacity retention up to 84.8% after 100 cycles at 0.1 C), showing the application prospects of high-entropy LGLZTSNO solid electrolyte in high-performance all solid state lithium batteries.

Breaking the Trade‐Off between Ionic Conductivity and Mechanical Strength in Solid Polymer Electrolytes for High‐Performance Solid Lithium Batteries

AbstractSolid polymer electrolytes (SPEs) are among the most promising candidates for solid‐state batteries due to their easy processibility, interface compatibility, and cost efficiency. However, the trade‐off between the ionic conductivity and mechanical strength of SPEs, which has persisted for decades, hinders their application in solid‐state lithium (Li) metal batteries. In this study, the aim is to break this trade‐off by utilizing poly(p‐phenylene benzobisoxazole) (PBO) nanofibers as a mechanically strong backbone and polyethylene oxide (PEO) as an ionically conductive network. The PBO/PEO composite electrolyte reduces the crystallinity of PEO while increasing the mechanical strength (74.4 MPa, ≈14 times that of PEO). Thus, PBO/PEO simultaneously improves ionic conductivity and mechanical strength both at room temperature and elevated temperatures, enabling uniform and smooth Li deposition. Thus, a long cycle life of solid‐state Li symmetric cells for 1000 h at 60 °C is achieved, and stable cycling of solid‐state Li metal full batteries at 60 °C and even 100 °C. Furthermore, the solid‐state pouch cell using this SPE exhibits excellent performance reliably after bending. The study clearly indicates that simultaneously improving mechanical properties and conductivity is the indispensable path to the practical application of solid‐state electrolytes.