Zwitterionic Sulfobetaine Hydrogel Electrolyte Building Separated Positive/Negative Ion Migration Channels for Aqueous Zn-MnO2 Batteries with Superior Rate Capabilities

Hydrogel electrolytes have attracted increasing attention due to their potential uses in the fabrication of flexible solid-state batteries. However, the development of hydrogel electrolytes is still in the initial stage and the number of available strategies is limited. Ideally, the hydrogel electrolyte should exhibit suitable ionic conductivity rate, mechanical strength, and biocompatibility for safety. In this study, a zwitterionic sulfobetaine/cellulose hydrogel electrolyte is fabricated using raw materials from natural plants, which exhibits a good biocompatibility with mammalian cells. The intrinsic zwitterionic groups on sulfobetaine chains can provide separated ion migration channels for positive and negative ions, which largely facilitates electrolyte ion transport. A solid-state Zn-MnO2 battery with a fabricated zwitterionic gel electrolyte exhibits a very high rate performance. It exhibits a specific capacity of 275 mA h gMnO2-1 at 1 C. Even up to 30 C, a high capacity of 74 mA h gMnO2-1 is maintained during the charging-discharging for up to 10 000 cycles. For wearable applications, the flexible solid-state batteries can be used as reliable and portable sources to power different wearable electronics such as a commercial smart watch, electroluminescent panel, and color electroluminescence line, which shows their large potentials for use in next-generation flexible and wearable battery technologies.