Solution-Processable Covalent Organic Framework Electrolytes\nfor All-Solid-State Li–Organic Batteries

Abstract

Solid electrolytes (SEs) are milestones\nin the technology roadmaps\nfor safe and high energy density batteries. The design of organic\nSEs is challenged by the need to have dynamic structural fluidity\nfor ion motion. The presence of well-ordered one-dimensional (1D)\nchannels and stability against phase transition in covalent organic\nframeworks (COFs) render them potential candidates for low-temperature\nSEs. Herein, we demonstrate two milestones using hydrazone COF as\nan SE: it achieves an ion conductivity of 10^–5 S\ncm^–1 at −40 °C with a Li⁺ transference number of 0.92 and also prevents the dissolution of\nsmall organic molecular electrode in all-solid-state batteries. Using\n1,4-benzoquinone as the cathode, a lithium battery using hydrazone\nCOF as a SE runs for 500 cycles at a steady current density of 500\nmA g^–1 at 20 °C. Considering that hydrazone\nCOF is readily amenable to large-scale production and facile post-synthetic\nmodification, its use in an all-solid-state battery is highly promising.