LiCoO2 sintering aid towards cathode-interface-enhanced garnet electrolytes

Garnet-type Li 7 La 3 Zr 2 O 12 (LLZO) has high ionic conductivity and good compatibility with lithium metal. High-temperature processing has been proven an effective method to decrease the interface resistance of cathode|LLZO. However, its application is still hindered by the interlayer co-diffusion with the cathode and high sintering temperature (>1200 °C). In this work, a new garnet-type composite solid-state electrolyte (SSE) Li 6.54 La 2.96 Ba 0.04 Zr 1.5 Nb 0.5 O 12 -LiCoO 2 (LLBZNO-LCO) is firstly proposed to improve the chemical stability and electrochemical properties of garnet with high-temperature processing. Small doses of LCO (3%) can significantly decrease the LCO|SSE interface resistance from 121.2 to 10.1 Ω cm 2 , while the sintering temperature of garnet-type LLBZNO decreases from 1230 to 1000 °C. The all-solid-state battery based on the sintered LLBZNO-LCO SSE exhibits excellent cycling stability. Our approach achieves an enhanced LCO|SSE interface and an improved sintering activity of garnet SSE, which provides a new strategy for optimizing the comprehensive performance of garnet SSE.