A Novel Organic Anode with 14 Electrons Participating in Redox Reactions Prepared Under Mild Conditions

Abstract

Covalent organic frameworks (COFs) have been widely used in various fields due to their abundant elemental resources, easy structure control, and abundant tunable porous structures. COFs containing electroactive organic groups with reversible redox behavior are potential electrode materials for next-generation high-performance lithium-ion batteries (LIBs). However, the aromatic conjugated structure of the backbone moiety in most reported COFs cannot participate in redox reactions, resulting in low capacity of COFs. At the same time, the synthesis processes of COFs are usually complicated and generally requires high temperature and high pressure. On this basis, an imine bond-rich COF (TAACOF) with reversible Li-ion bonding is developed, which has the advantages of facile preparation and low energy consumption. In particular, the lone pair electrons of the N atom in the imine bond can induce lithium ions to combine with the aromatic conjugated structure, which greatly improves the capacity of the TAACOF electrode. After 800 cycles, the active sites of the TAACOF are fully activated, and after a 14-electron redox reaction, the specific capacity can reach as high as 1035.7 mAh g-1.

Keywords: lithium ion battery, Anode, Covalent organic framework, high performance, Lithium storage mechanism.