Enhanced High-Temperature Cycling Stability of Garnet-Based All Solid-State Lithium Battery Using a Multi-Functional Catholyte Buffer Layer

The pursuit of safer and high-performance lithium-ion batteries(LIBs)has triggered extensive research activities on solid-state batteries,while challenges related to the unstable electrode-electrolyte interface hinder their practical implementation.Polymer has been used extensively to improve the cathode-electrolyte interface in garnet-based all-solid-state LIBs(ASSLBs),while it introduces new concerns about thermal stability.In this study,we propose the incorporation of a multi-functional flame-retardant triphenyl phos-phate additive into poly(ethylene oxide),acting as a thin buffer layer between LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode and garnet electro-lyte.Through electrochemical stability tests,cycling performance evaluations,interfacial thermal stability analysis and flammability tests,improved thermal stability(capacity retention of 98.5%after 100 cycles at 60℃,and 89.6%after 50 cycles at 80℃)and safety characteristics(safe and stable cycling up to 100℃)are demonstrated.Based on various materials characterizations,the mechanism for the improved thermal stability of the interface is proposed.The results highlight the potential of multi-functional flame-retardant additives to address the challenges associated with the electrode-electrolyte interface in ASSLBs at high temperature.Efficient thermal modification in ASSLBs operating at elevated temperatures is also essential for enabling large-scale energy storage with safety being the primary concern.

Optimization of two-dimensional solid-state electrolyte-anode interface by integrating zinc into composite anode with dual-conductive phases

Solid-state electrolytes(SSEs)are a solution to safety issues related to flammable organic electrolytes for Li batteries.Insufficient contact between the anode and SSE results in high interface resistance,thus causing the batteries to exhibit high charging and discharging overpotentials.Recently,we reduced the overpotential of Li stripping and plating by introducing a high proportion of dual-conductive phases into a composite anode.The current study investigates the interface resistance and stability of a composite electrode modified with Zn and a lower proportion of dual-conductive phases.Zn-cation-adsorbed Prussian blue is synthesized as an intermediate component for a Zn-modified composite electrode(Li-FeZnNC).The Li-FeZnNC symmetric cell presents a lower interface resistance and overpotential compared with Li-FeNC(without Zn modification)and Li-symmetric cells.The Li-FeZnNC symmetric cell shows high electrochemical stability during Li stripping and plating at different current densities and high stability for 200 h.Full batteries with a Li-FeZnNC composite anode,garnet-type SSE,and LiFePO4 cathode show low charging and discharging overpotentials,a capacity of 152 mAh g^(−1),and high stability for 200 cycles.