Breaking Low-Temperature Bottlenecks via p-d-π-Type Local Environment toward High-Performance Polymer-Based All-Solid-State Lithium Battery.

Polymer-based composite solid electrolytes (CSEs) suffer from extremely slow bulk/interface Li+ transport and poor interfacial stability at room temperature (RT) and low temperature (LT) in all-solid-state lithium batteries (ASSLBs). Herein, we design a novel p-d-π-type local environment in polymer CSEs to break the bulk/interfacial Li+ kinetic bottlenecks and construct LT high-performance ASSLBs. The customized anion-rich association state from ternary lithium salts (FSI-, DFOB-, and NFSA-) breaks the strong ion-association environment, and the cations-π interactions trigged by nickel phthalocyanine supplies extra Li+ transport sites, which considerably enhances the ionic conductivity (25 °C: 1.31 mS·cm-1; 0 °C: 0.70 mS·cm-1; -40 °C: 0.10 mS·cm-1). Moreover, the delocalized π-electrons and Ni(3d)-O(2p) orbital hybridization accelerate the interfacial charge transference and the formation of LiF-LiNxOy/B-O/B-F-rich interphases, greatly improving the dual-interface compatibility and long-term stability. ASSLBs with the LiFePO4 cathode demonstrate large rate capacity (115.6 mAh·g-1@6.0C), superhigh cycling stability (90.3% retention after 1000 cycles at 4.0C) at RT, and prominent LT performance (0 °C: 106.52 mAh·g-1@1.0C, 100% retention after 500cycles; -20 °C: 100% retention after 200 cycles at 0.2C). The pouch cell shows a capacity retention of 90.75% after 700 cycles at 3.0C. ASSLBs employing LiNi0.9Co0.05Mn0.05O2 cathode display a 100% retention after 500 cycles at 1.0C, and it can work even at -37.8 °C. This work addresses the critical challenges of polymer ASSLBs in high-rate and LT and should promote their practical applications.