Conductive metal–organic framework with redox metal center as cathode for high rate performance lithium ion battery

Abstract

Exploration of new materials for lithium ion battery is a continuous challenge to meet the increasing demand for energy storage. Herein, a novel conductive metal-organic framework Cu3(2,3,6,7,10,11-hexahydroxytriphenylene)2 (Cu3(HHTP)2) is obtained and tested as cathode active material in lithium ion battery. With a working voltage range of 1.7–3.5 V, Cu3(HHTP)2 cathode shows a reversible discharge and charge capacity of ∼95 mA h g−1, which is almost equal to its theoretical value. Impressively, this novel cathode also shows highly stable redox cycling performance at the current rate as high as 20C because of its intrinsic electrical conductivity and two dimensional porous structure. Electrochemical properties and chemical analysis of Cu3(HHTP)2 reveal that the valence change of copper cations in the framework is responsible for the lithium ions insertion/desertion during redox cycles. The first principle calculation also supports this mechanism.