Tuning Electron Delocalization of Redox‐Active Porous Aromatic Framework for Low‐Temperature Aqueous Zn−K Hybrid Batteries with Air Self‐Chargeability.

Air self‐charging aqueous batteries promise to integrate energy harvesting technology and battery systems, potentially overcoming a heavy reliance on energy and the spatiotemporal environment. However, the exploitation of multifunctional air self‐charging battery systems using promising cathode materials and suitable charge carriers remains challenging. Herein, for the first time, we developed low‐temperature self‐charging aqueous Zn−K hybrid ion batteries (AZKHBs) using a fully conjugated hexaazanonaphthalene (HATN)‐based porous aromatic framework as the cathode material, exhibiting redox chemistry using K+ as charge carriers, and regulating Zn‐ion solvation chemistry to guide uniform Zn plating/stripping. The unique AZKHBs exhibit the exceptional electrochemical properties in all‐climate conditions. Most importantly, the large potential difference causes the AZKHBs discharged cathode to be oxidized using oxygen, thereby initiating a self‐charging process in the absence of an external power source. Impressively, the air self‐charging AZKHBs can achieve a maximum voltage of 1.15 V, an impressive discharge capacity (466.3 mAh g−1), and exceptional self‐charging performance even at −40 °C. Therefore, the development of self‐charging AZKHBs offers a solution to the limitations imposed by the absence of a power grid in harsh environments or remote areas. [ABSTRACT FROM AUTHOR]