Co‐Based Metal–Organic Frameworks With Dual Redox Active Centers for Lithium‐Ion Batteries With High Capacity and Excellent Rate Capability

Abstract

AbstractSmall molecule organic materials are widely used as anode materials for lithium‐ion batteries (LIBs) due to their high reversible capacity, designable structure, and environmental friendliness. However, they suffer from poor intrinsic electronic conductivity, severe dissolution, and low initial coulombic efficiency. Recently, metal–organic frameworks (MOFs) have demonstrated in metal‐ion batteries, outperforming some small molecule organic materials in terms of both cycling stability and rate capability. Herein, the first rational design and synthesis of a new cobalt‐based MOF (CoBPDCA), are reported employing cobalt(II) nitrate as the metal source and small organic molecules (2,2‐bipyridyl‐4,4‐dicarboxylic acid, BPDCA) as the ligands, which shows exceptional chemical stability and impressive electron conductivity. Most importantly, CoBPDCA electrodes deliver a high reversible capacity of 1112.9 mAh g−1 at 0.05 C (1 C = 1000 mA g−1) and outstanding high‐rate durability (166.3 mAh g−1 after 2500 cycles at 10 C). Employing a series of spectroscopic and morphological characterizations and density functional theory (DFT) calculations, it is revealed that these impressively electrochemical performances are contributed to the dual active redox centers of Co cations and BPDCA ligands (CN and CO groups), and the superb electron conductivity. This work might provide a new strategy and a deeper understanding of the other MOFs' development for LIBs.