Cyclooctatetrathiophene Based MOF-Derived Porous Materials as High-Performance Anode for Lithium-Ion Batteries

Extensive research on anodes with higher capacity than carbon-based materials is driven by the great demand for lithium-ion batteries with higher energy density. However, the cycling stability of high-capacity anodes is usually hindered by significant volumetric changes and structural collapse during the cycling process. Metal-organic frameworks (MOFs) are an emerging class of crystalline materials, and their derivatives are expected as alternative high-capacity anodes, resulting from the merits of easy functionalization and pore engineering. In this study, a novel porous Co-MOF-derived composite anode was prepared by the pyrolysis of a nonporous Co-cyclooctatetrathiophene tetrapyridine (Co-COTTTP) template. X-ray absorption spectroscopy and high-resolution transmission electron microscopy revealed that the precise composition of Co-COTTTP-derived composite anodes with exposed rich redox cobalt oxides active sites, appropriate degree of graphitization, and N, S-doping, which effectively enhanced the electrochemical performance of the composite anodes. Thus, the resulting porous MOF-derived composite anode demonstrated high specific capacity and long cycling stability in the assembled batteries. Specifically, the cells assembled with Co-COTTTP-500 anodes delivered a high reversible specific capacity of 1005.7 mAh/g after 100 cycles at 0.1 A/g and can be cycled steady for 800 cycles at 1 A/g, indicating the structure stability during cell operation. In summary, this study provides a feasible strategy to prepare high-performance MOF-derived anodes and deep understanding for the structure–activity relationship, contributing to the fabrication of high-energy–density lithium-ion batteries.