A mechanically durable and device-level tough Zn-MnO₂ battery with high flexibility

Practical application of flexible energy storage devices has not been realized despite the booming of experimental researches. One major concern is their poor mechanical durability, which has seldom been investigated in literatures. On one hand, their flexibility is not good enough to accommodate arbitrary deformations, which was merely demonstrated by statically bending at certain angles. Thus, stability against dynamic mechanical stimuli is highly desired. On the other hand, these devices are not strong enough to endure severe mechanical stimuli including large shear forces and impacts, which greatly limits their practicability. Therefore, device-level toughness to ensure long-term usability is also needed. Here, a mechanically durable Zn-MnO₂ battery is developed based on a dual-crosslinked hydrogel electrolyte without the usage of separator. Due to the effective energy dissipation of the hydrogel, the as-fabricated battery maintains a stable energy output when being dynamically deformed under severe mechanical stimuli. It can be vastly deformed into various shapes without electrochemical performance decay, showing excellent flexibility. It also exhibits super toughness that can endure two days’ treading pressure and survive 20 times of random run-over by cars on road. These demonstrations reveal its outstanding mechanical stability and durability, suggesting great potential in truly flexible and wearable applications.