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.