Optimization of ion/electron channels enabled by multiscale MXene aerogel for integrated self-healable flexible energy storage and electronic skin system

MXenes have received extensive attention in the fields of energy storage and flexible electronics due to their excellent physicochemical properties. However, MXenes are prone to self-stacking, which would result in severely degraded performance of the electronic devices. Unlike the optimization of the structure-property relationship of MXene at specific scale in most reported studies, the current work is based on the multiscale design concept: MXene aerogels with abundant ion/electron channels are constructed through an efficient chemical oxidation and rapid gas foaming strategy. Nanoscale in-plane nanoporous MXenes can lead to increased ion channels and effectively shortened ion transport distances. Micron-scale MXene aerogels can provide abundant ionic active sites and maximized electron channels. The fabricated integrated self-healable flexible zinc-ion energy storage and pressure sensing system offers high areal specific capacitance of 576 mF cm2, sufficient energy density of 156.8 uWh cm-2 at a power density of 4200 uW cm2, and ultra-high pressure sensitivity (1024.9 kPa1), which has great potential in applications including self-healing and flexible wearable devices. The multiscale design concept achieves the maximization of ion/electron channels, realizing a thoughtful strategy for the optimization of flexible electronic devices.