Self‐Activation Enables Cationic and Anionic Co‐Storage in Organic Frameworks

The low capacity of current anion‐hosting electrodes makes it challenging to meet future energy requirements. Maintaining the high capacity of ions per unit volume and/or weight is always the ultimate goal for an optimal electrode design. Here, an organic framework is reported that can efficiently co‐store anions and cations in a single discharge/charge process, accompanied with a special cation‐assisted electrode activation process. The inserted cations not only facilitate anion diffusion kinetics, but also make a considerable contribution to the total capacity of the electrodes. This anion–cation co‐storage cathode thus can deliver a high capacity of 530 mAh g−1 at 3.4–1.0 V and a high energy density of 901 Wh kg−1 after 800 cycles (at 0.15 A g−1). The understanding of the self‐activation process is expected to inspire electrode design that utilizes anionic–cationic hybrid electrode chemistries beyond current Li‐ion batteries.