Monolithic in situ assembly of seamless hydrogel interfaces for high-performance and mechanically adaptive flexible energy storage

Hydrogel-based flexible electronic energy storage devices have already played a significant role in enabling the rapid development of wearable electronic devices. However, the imbalance between the electrical performance and biocompatibility of hydrogel materials and the weak interactions between electrodes and electrolytes still restrict the development of hydrogel energy storage devices. Herein, a Zn-MnO 2 flexible electronic energy storage system based on hydrogel materials is presented. First, a filler-free hydrogel electrode is fabricated by phase segregation of a pure conductive polymer network treated with an ionic liquid, which exhibits high electrical conductivity and flexibility. Then, polysaccharide materials are introduced into the hydrogel electrolyte to adjust the network structure, which demonstrates higher ion conductivity and flexibility. Moreover, the electrolyte is in-situ polymerized on the surface of the electrode to form a topology of connection between the hydrogel electrode and the electrolyte, thus ensuring the high specific capacity (150 mAh/g at a current density of 0.4 A/g) and relatively stable electrochemical performance under deformation. Last but not least, the device could be integrated with hydrogel electronics to achieve message transmission and health monitoring, verifying the application of energy supply for wearable electronics. It is believed that such a system will provide a pathway to a stable energy supply for flexible electronics.