A flexible, ion-conducting solid electrolyte with vertically bicontinuous transfer channels toward high performance all-solid-state lithium batteries

All-solid-state lithium batteries, featuring high security and volume energy density, hold great potential as next-generation energy storage device. However, their development needs the fabrication of ionic conductive and structural stable solid electrolyte. Herein, Li0.33La0.557TiO3 (LLTO) framework with interlocked porous structure is synthesized by sintering the gel permeated nylon. Then, poly(ethylene oxide) (PEO) is incorporated in the pores to produce PEO-LLTO framework solid electrolyte (PLLF electrolyte) with vertically bicontinuous phase. We demonstrate that LLTO framework fast transports Li+ through the intrinsic vacancy; meanwhile the confined PEO with low crystallization displays fast Li+ transfer ability, thus synergistically realizing efficient Li+ conduction. This novel PLLF electrolyte exhibits a remarkable ionic conductivity of 2.04 × 10−4 S cm−1, which is ~72 times higher than that of traditional PEO-based electrolytes and superior to most reported solid electrolytes. Moreover, the interconnected networks endow PLLF electrolyte with excellent structural stability. Thus, the LiFePO4 (LFP)/Li cell exhibits extraordinary cycling stability: the discharge capacity of 154.7 mAh g−1 at 1 C after 150 cycles with capacity decay of only 0.03% per cycle. Briefly, such a vertically bicontinuous phase structure maximizes the cooperation between the conduction function of ceramic framework and the stability of polymer, offering a promising approach for all-solid-state batteries.