High-areal-capacity all-solid-state lithium batteries enabled by rational design of fast ion transport channels in vertically-aligned composite polymer electrodes

摘要

All-solid-state lithium batteries (ASSLBs) assembled with solid polymer electrolytes (SPEs) have been regarded as promising next-generation rechargeable batteries with improved safety and high energy densities. However, the Li dendrites and poor Li+ transport greatly inhibit their practical applications when coupled with relatively high loading cathodes. Herein, we combine a glass fiber (GF)-reinforced composite polymer electrolyte based on poly(ethylene oxide) (labeled as PEO@GF) to suppress Li dendrite growth with a freeze-casted vertically-aligned (VL) electrode to facilitate Li+ transport in the high loading cathode. Benefiting from the enhanced mechanical strength and uniformed Li deposition enabled by the implanted GF, the Li-Li symmetric cells exhibit significantly improved cycling stability up to 2000 h (0.2 mA cm(-2), 0.2 mAh cm(-2)) and 1000 h (0.42 mA cm(-2), 0.4 mAh cm(-2)), which are over one order of magnitude longer than those of the pure PEO electrolyte. Furthermore, VL-LiFePO4 (LFP) cathode divides the thick electrode into numerous vertically-aligned "thin electrodes", which significantly decreases the Li+ transport distance and enables the Li vertical bar PEO@GF vertical bar VL-LFP cell with a high LFP loading of 10.5 mg cm(-2) to deliver a high areal capacity of 1.52 mAh cm(-2). The rational structure design of both electrolyte and electrode offers an opportunity for developing high-performance ASSLBs with high active material loadings.