Recently advances in flexible zinc ion batteries

Flexible batteries are key component of wearable electronic devices. Based on the requirements of medical and primary safety of wearable energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) are promising portable candidates in virtue of its intrinsic safety, abundant storage and low cost. However, many inherent challenges have greatly hindered the development in flexible Zn-based energy storage devices, such as rigid current collector and/or metal anode, easily detached cathode materials and a relatively narrow voltage window of flexible electrolyte. Thus, overcoming these challenges and further developing flexible ZIBs are inevitable and imperative. This review summarizes the most advanced progress in designs and discusses of flexible electrode, electrolyte and the practical application of flexible ZIBs in different environments. We also exhibit the heart of the matter that current flexible ZIBs faces. Finally, some prospective approaches are proposed to address these key issues and point out the direction for the future development of flexible ZIBs.