Dual Active Site of the Azo and Carbonyl-Modified Covalent Organic Framework for High-Performance Li Storage

Abstract

Organic electrode materials play a crucial role in environmentally friendly and sustainable lithium-ion batteries (LIBs) due to their abundance, high theoretical capacity, inexpensiveness, and recyclability. However, critical issues such as fewer redox-active sites and poor structural stability limit their extensive application in LIBs. Herein, a unique covalent organic framework (Tp-Azo-COF) with a dual active site of N═N and C═O is designed and successfully applied as the anode material for LIBs. Benefiting from its abundance of active sites, large conjugate structure, large surface area, and accessible Li+ transport channels, the Tp-Azo-COF anode materials present high electrochemical kinetics and structural stability. The assembled LIBs deliver a specific capability of 305.97 mAh g–1 at a current density of 1000 mA g–1 after 3000 cycles. This work may inspire avenues for the development of advanced organic materials of inexpensive, sustainable, and durable rechargeable batteries.