Introducing low-tortuosity channels in thick electrode for high-areal-capacity solid polymer battery

All-solid-state lithium battery (ASSLB) is the most promising candidate of next generation lithium ion batteries. However, the construction of high loading composite electrode is a bottleneck of ASSLB. Herein, low-tortuosity LiFePO4 (LFP-LT) composite electrodes with high mass loadings are prepared by a phase inversion and in-situ polymerization method. The in-situ formed polymer electrolyte possesses a wide electrochemical window (0–4.9 V vs Li+/Li), high lithium-ion transference number (0.73) and a high Li+ conductivity (0.23 mS cm−1) at room temperature. In addition, the low-tortuosity channels can serve as fast electron/ion pathways. Consequently, the LFP-LT composite electrode with a loading of 15 mg cm−2 shows an excellent cycling stability with a capacity retention of 89.0 % after 250 cycles at 1C. Notably, an ultra-high loading LFP-LT composite electrode (35 mg cm−2) displays a high areal capacity of 5 mAh cm−2 and an enhanced cycling performance with a capacity retention of 94.0 % after 150 cycles at 0.5C. This work presents an efficient strategy to construct low-tortuosity and high loading solid polymer batteries.