Li_1·5Al_0·3Si_0·2Ti_1·7P_2·8O₁₂ inorganic solid electrolyte for high-performance all-solid-state Li-ion batteries

Commercial Li-ion batteries are vital to our daily lives, powering everything from portable devices to high-powered electric vehicles. The current usage of flammable liquid electrolytes in conventional Li-ion batteries creates risks, necessitating the development of solid electrolytes that are secure and reliable. However, the ionic conductivity of solid electrolytes cannot compete with liquid electrolytes. Herein, we report the synthesis of Li_1·5Al_0·3Si_0·2Ti_1·7P_2·8O₁₂ (LASTP) powder with improved ionic conductivity and evaluate its performance as a solid electrolyte in an all-solid-state battery (ASSB). A facile solution-based method is used for the LASTP synthesis with optimized sintering and calcination temperatures. As a result, the LASTP sintered at 1050 °C has the highest relative density (96.84%) and ionic conductivity (9.455 × 10⁻⁴ S/cm) with the lowest activation energy (E_a, 0.226 eV). A coin cell is assembled with Li/LASTP/Li(Ni_0·65Co_0·15Mn_0.20)O₂ all-solid-state configuration to evaluate the electrochemical performance. In addition, an electrospun polymer conductor film (PVDF-HFP) is added between the electrodes and the solid electrolyte to reduce the interfacial resistance. The ASSB has shown a stable and high performance with remarkable discharge capacity (205.3 mAh/g) at 0.1C and could be operated even after 100 cycles with 85.3% of retention at 0.2C. Therefore, the present work suggests that the LASTP solid electrolyte is a promising material for next-generation safe ASSBs.