Recent advances in flexible aqueous zinc-based rechargeable batteries

Flexible aqueous Zn battery has exhibited great potential as a power source for flexible and wearable electronic devices due to its unique features, such as high safety, low cost, and eco-friendliness. Numerous studies on flexible Zn batteries have been reported and exciting achievements have been obtained in the past few years. However, there are still many problems in the electrode design and the assembly process to acquire desirable flexibility without sacrificing the capacity. This review summarizes the up-to-date advances in flexible Zn batteries. We first introduce the recent progresses in anodes, cathodes and solid-state electrolytes. Special emphases are then put on the discussions of differences between various flexible current collectors or substrates. Electrode preparation techniques and flexible battery assembly technologies are also compared and discussed. Finally, challenges toward further developments of flexible Zn batteries with high capacity, excellent flexibility and cycling stability are proposed. Future research trends and highlights are suggested as well.