Solution Processable Covalent Organic Framework Electrolytes for All-Solid-State Li Organic Batteries

Abstract

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