High‐Potential Cathodes with Nitrogen Active Centres for Quasi‐Solid Proton‐Ion Batteries

Abstract Although proton‐ion batteries have received considerable attention owing to their reliability, safety, toxin‐free nature, and low cost, their development remains in the early stages because of lacking proper electrolytes and cathodes for facilitating a high output voltage and stable cycle performance. We present a novel cathode based on active nitrogen centre, which provides a flat discharge plateau at 1 V with a capacity of 115 mAh g −1 and excellent stability. Moreover, a quasi‐solid electrolyte was developed to overcome the issue of corrosion, broaden the potential window of the electrolyte, and prevent the active material from dissolving. While using the unique as‐developed electrolyte, the newly designed cathode retained 89.67 % of its original capacity after 2000 cycles. Finally, we demonstrated the excellent cycle performance of the as‐developed metal‐free, flexible, soft‐packed battery. Notably, even when a portion of the battery was cut off, it continued to function normally.