Electrochemical Properties of a Multicarbonyl Polyimide Superstructure as a Hierarchically Porous Organic Anode for Lithium-Ion Batteries

Organic carbonyl compounds have been widely investigated as a promising candidate for graphite anodes in lithium-ion batteries (LIBs) because of their high capacity, low cost, and diverse structure. Here, a multicarbonyl polyimide derivative bearing an anhydride with benzoquinone was designed and synthesized by a simple hydrothermal method. Integrating flexible structural design with careful regulation of polymerization conditions, the polyimide derivative exhibits an unprecedented three-dimensional microsphere-like superstructure constructed by interconnected two-dimensional nanosheets, which is beneficial to trigger interfacial energy storage and improve storage capacity. When explored as an anode material for LIBs, the polyimide derivative delivers an outstanding reversible capacity (992 mAh/g at 100 mA/g), good rate capability (268 mAh/g at 2 A/g), and excellent cycle stability (465 mAh/g after 150 cycles at 0.5 A/g). Based on density functional theory calculations and experimental results, a 24 Li-storage mechanism with a five-step lithiation/delithiation process is proposed.