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

摘要

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.