A soft yet device-level dynamically super-tough supercapacitor enabled by an energy-dissipative dual-crosslinked hydrogel electrolyte

Three challenges remain unsettled for current flexible energy storage devices. One is that most developed devices are not soft enough to conform various deformations; another is that they can hardly guarantee a stable energy output when being dynamically deformed―most of the ever-reported tests on flexibility are performed under static conditions; the third is that they lack sufficient toughness at device level, meaning they are vulnerable to severe mechanical stresses. We believe these problems must be well settled before wearable devices can be practically applied. Here we report a hydrogel with excellent energy-dissipating ability that can be simultaneously used as high-performance electrolyte, super-tough separator and highly effective electrode protector for supercapacitors. The developed supercapacitor is highly soft and super tough at device level. It can well maintain its stable output when being dynamically bent and exhibits high resistance to severe mechanical stimuli including blade-cut, hammering, etc. It can be arbitrarily deformed into irregular shapes while keeping original performances. Moreover, it can even survive extremely harsh conditions including 6 days’ treading and 50 times of car run-over without notable deterioration in capacitance and long-term stability. This super tough supercapacitor shows great potential in truly wearable applications involving severe mechanical stresses and impacts.