Polynitrosoarene Radical as an Efficient Cathode Material for Lithium-Ion Batteries

Organic radical batteries (ORBs) with radical-branched polymers as cathode materials represent a valuable alternative to meet the continuously increasing demand on energy storage. However, the low theoretical capacities of current radical-contained compounds strongly hamper their practical applications. To address this issue, a chemically robust polynitrosoarene (tris(4-nitrosophenyl)amine) with a pronounced radical property is rationally designed as an efficient cathode for ORBs. Its unique multi-nitroso structure displays remarkably reversible charge/discharge capability and a superior capacity up to 300 mA h g^-1 (93% theoretical capacity) after 100 cycles at 100 mA g^-1 within a broad potential window of 1.3-4.3 V (vs Li⁺/Li). Moreover, the ultra-long cycle life is also achieved at 1000 mA g^-1 with 85% preservation of the capacity after 1000 cycles, making it the best-reported organic radical cathode material for lithium-ion batteries.