3D Porous Garnet/Gel Polymer Hybrid Electrolyte for Safe Solid-State Li-O2 Batteries with Long Lifetimes

Li-O-2 battery is a promising rechargeable battery candidate due to its ultrahigh theoretical energy density. However, safety issues and poor cycling stability of Li-O-2 batteries caused by the formation of Li dendrites and the use of organic liquid electrolytes inhibit their practical applications. Here, we propose a hybrid solid electrolyte composed of three-dimensional (3D) porous garnet microstructure (PSSE) infused with gel polymer electrolyte (GPE) (PSSE/GPE) to enhance the safety and cycling stability of Li-O-2 batteries. In this hybrid solid electrolyte, the 3D garnet microstructure serves as a rigid backbone to suppress Li dendrites, while the consecutive GPE in PSSE serves as an ionic highway, ensuring a high ionic conductivity (1.06 x 10(-3) S cm(-1)) in the bulk. Besides, the hybrid electrolyte offers the ability to block O-2 crossover and maintain good compatibility with Li metal anode and advanced air electrode. As a result, the cycle life of Li symmetric cell is dramatically improved almost 60 times (6000 h, 250 days) by replacing GPE with PSSE/GPE. The Li-O-2 battery based on PSSE/GPE shows a long cycle life of 194 cycles with a high cycling capacity of 1250 mA h g(-1). The present study demonstrates a novel class of hybrid solid electrolyte for high-performance solid-state Li-O-2 batteries.