The Design of Quaternary Nitrogen Redox Center for High-Performance Organic Battery Materials

Redox-active organic compounds attract broad research interest as a competitive candidate for battery electrode materials, owing to their structural diversity and elemental abundance. Currently, carbonyls, aza-derivatives, nitroxyl radicals, and thioethers dominate the research activities. However, the redox process of these compounds often involves chemical bond rearrangement or the formation of active intermediates, which seriously destabilize the structure. Here, we introduce an alternative strategy by using a quaternary nitrogen redox center for the design of stable organic battery materials. In such a strategy, empty orbital or lone pair electrons of the redox center participate in conjugation. During the redox reaction, the redox center is stabilized through conjugation without chemical bond rearrangement, thereby enhancing its stability. The oligomer of 5,10-diphenyl-dihydrophenazine following the proposed design strategy shows impressive cycling stability along with high redox potential, high thermal stability, and high specific energy and power density that are comparable with or superior to present organic cathode materials.