Perovskite CsPbI3 Nanowire-Reinforced PEO Electrolytes Toward High-Rate All-Solid-State Lithium–Metal Battery

Polymer solid-state electrolytes (SSEs) usually suffer from low ionic conductivity and interface instability between the electrolyte and lithium metal. Herein, a strategy using perovskite CsPbI3 nanowires (CsPbI3–NWs) to reinforce the poly(ethylene oxide) (PEO) electrolyte (PLN) has been developed to build a high-rate all-solid-state lithium–metal battery (ASSLMB). The principle is that the addition of CsPbI3–NWs significantly reduces the crystallinity of PEO and promotes the dissociation of Li+-ion, therefore leading to a large Li+-ion migration number (tLi+) (0.61) and excellent ionic conductivity (1.66 × 10–4 S cm–1) at 30 °C. Meanwhile, the lithium dendrite growth is effectively suppressed and a stable SEI is formed in the Li|PLN|Li ASSLMB. Moreover, the Li|PLN|LiFePO4 ASSLMBs possess remarkable rate capability (∼94.3 mAh g–1 under 5C), high Coulombic efficiency (CE) (∼99.7% on average), and cycling stability (8.6% capacity loss for 200 cycles at 0.8C) at 90 °C. This work reveals that CsPbI3–NW-reinforced PEO-based SSE is a good candidate to develop high-performance ASSLMBs by increasing the ionic conducting ability and promoting the formation of a stable electrochemical interface.