Symmetric All‐Organic Battery Containing a Dual Redox‐Active Polymer as Cathode and Anode Material

All‐organic batteries are a promising sustainable energy storage technology owing to the wide availability, flexibility, and recyclability of organic/polymeric compounds. The development of all‐organic or polymer batteries is still a challenge, as both electrode materials need to be carefully optimized to have a wide difference of redox potential and compatibility with the electrolyte. Herein, dual redox‐active polyimides based on phenothiazine and naphthalene tetracarboxylic dianhydride units are presented. After only one optimization step, the electrodes based on these dual redox polymers can be applied simultaneously as anode and cathode in a symmetric all‐organic battery. The phenothiazine functional polyimide shows two redox active voltages at around 2.5 and 3.7 V (vs. Li/Li+) with high discharge capacities of 160 mAh g−1. Moreover, the symmetric full battery delivers high power density up to 1542 W kg−1 with stable cyclability for 1000 cycles. This work demonstrates an efficient strategy to develop dual redox active polymer electrodes for next generation all‐polymer batteries. Dual‐ing polymers: A phenothiazine and naphthalene‐polyimide‐based redox polymer is applied as both cathode and anode material to build a symmetric polymer–polymer battery with good cycling stability for 1000 cycles at 800 mA g−1 and outstanding power density up to 1542 W kg−1.