Phenothiazine-Functionalized Poly(norbornene)s as High-Rate Cathode Materials for Organic Batteries.

Organic cathode materials are handled as promising candidates for new energy-storage solutions based on their transition-metal-free composition. Phenothiazine-based polymers are attractive owing to their redox potential of 3.5 V vs. Li/Li+ and high cycling stabilities. Herein, three types of poly(norbornene)s were investigated, functionalized with phenothiazine units through either a direct connection or ester linkages, as well as their crosslinked derivatives. The directly linked poly(3-norbornylphenothiazine)s demonstrated excellent rate capability and cycling stability with a capacity retention of 73 % after 10 000 cycles at a C-rate of 100 C for the crosslinked polymer. The polymer network structure of the crosslinked poly(3-norbornylphenothiazine) was beneficial for its rate performance.