Highly Conductive Two-Dimensional Metal–Organic Frameworks for Resilient Lithium Storage with Superb Rate Capability
Zhenzhen Wu, David Adekoya, Xing Huang, Milton J. Kiefel, Jian Xie, Wei Xu, Qichun Zhang, Daoben Zhu, Shanqing Zhang
Abstract
Redox-active organic cathode materials have drawn growing attention because of the broad availability of raw materials, eco-friendliness, scalable production, and diverse structural flexibility. However, organic materials commonly suffer from fragile stability in organic solvents, poor electrochemical stability in charge/discharge processes, and insufficient electrical conductivity. To address these issues, using Cu(II) salt and benzenehexathiolate (BHT) as the precursors, we synthesized a robust and redox-active 2D metal–organic framework (MOF), [Cu3(C6S6)]n, namely, Cu-BHT. The Cu-BHT MOFs have a highly conjugated structure, affording a high electronic conductivity of 231 S cm–1, which could further be increased upon lithiation in lithium-ion battery (LIB) applications. A reversible four-electron reaction reveals the Li storage mechanism of the Cu-BHT for a theoretical capacity of 236 mAh g–1. The as-prepared Cu-BHT cathode delivers an excellent reversible capacity of 175 mAh g–1 with ultralow capacity deterioration (0.048% per cycle) upon 500 cycles at a high current density of 300 mA g–1. Therefore, we believe this work would provide a practical strategy for the development of high-power energy storage materials.