Crosslinked Polyimides as Cathodes for Lithium-Ion Batteries

Organic cathode materials for lithium-ion batteries are becoming increasingly popular because of their structural flexibility, resource abundance, and environmental friendliness. However, their application is limited by their solubility in electrolytes, which leads to the rapid decay of cycling performance. Herein, we synthesize crosslinked polyimides by condensation polymerization between 3,4,9,10-perylenetetracarboxylic dianhydride and 1,2-ethanediamine in the presence of a trifunctional crosslinker of diethylenetriamine. The synthesized crosslinked polyimides present a porous structure with a high surface area. The crosslinked polyimide cathode materials used in lithium metal half-cells have a high discharge capacity of 160.3 mA h g–1 at a current density of 30 mA g–1, and the assembled lithium-ion batteries maintain 77% capacity after 2000 cycles at a current density of 150 mA g–1, which is much better than that of lithium-ion batteries employing linear polyimides, demonstrating that crosslinked polyimides may be potential cathode materials for high-performance lithium-ion batteries.