Multifunctional Quasi-Solid State Electrolytes Based on “Reverse” Plant Cell Structure for High-Performance Lithium Metal Batteries

Quasi-solid state electrolytes (QSSEs) combine the benefits of both solid and liquid electrolytes, making them promising for high-performance lithium metal batteries (LMBs). However, developing QSSEs that achieve high ionic conductivity, a continuous electrode/electrolyte interface, and significant mechanical robustness remains challenging. Plant cell walls provide mechanical strength, while the cell membrane offers excellent material transport capabilities, making them effective models for quasi-solid electrolytes. However, using plant cells as a model can result in poor interface contacts due to the rigid components on the exterior. To address this, a "reverse" plant cell QSSE with a multifunctional bilayer architecture has been proposed. The outer layer acts as a functional reaction interface to enhance Li⁺ transmission, improve interfacial contact, and significantly reduce interfacial impedance. Meanwhile, the inner layer is designed to provide mechanical robustness and shorten ion transport distances. The QSSE inspired by "reverse" plant cells has an ionic conductivity of 4.26 × 10−3 S cm−1, a Li+ transference number (tLi+) of 0.91, and an electrochemical stability window (ESW) of 4.83 V. Li−LiFePO4 (LFP) full cells based on the "reverse" plant cell QSSE can maintain a cycling capacity of 137 mAh g−1 after 500 cycles at 1 C, with 95% retention.