Cross-Linked Naphthalene Diimide-Based Polymer as a Cathode Material for High-Performance Organic Batteries

In the field of rechargeable batteries, redox organic compounds have attracted huge attention owing to their eco-friendliness, resource abundance, good flexibility, and low cost. However, the high solubility of the organic compounds in electrolytes results in poor cell performance. In this paper, we report that a cross-linked naphthalene diimide-based polymer, which is a three-dimensional network structure, exhibits outstanding cell performance in organic batteries. The polymer is synthesized by the imidization condensation of naphthalene-1,4,5,8-tetracarboxylic dianhydride (NDA) and 4-vinylaniline to form N,N′-di(4′-vinylphenyl)naphthalene-1,4,5,8-dicarboxydiimide (DVP-NDI) and by subsequent radical polymerization to a cross-linked DVP-NDI (CL-DVP-NDI) polymer. The cross-linking of the polymer is characterized using infrared and solid-state 13C nuclear magnetic resonance spectroscopy. Thermogravimetric analysis shows that the polymer with a three-dimensional network structure exhibits better thermal stability than an organic molecule. The solubility test indicated that the CL-DVP-NDI polymer can suppress the dissolution of the polymer in organic electrolytes. The discharge capacity of the CL-DVP-NDI electrode is 121.3 mAh g–1 at a C-rate of 0.2 C. The cycle-life performance of the Li||CL-DVP-NDI cell is 84% remaining after 200 cycles at a charging–discharging rate of 1 C.