Metal Ion-Induced Porous MXene for All-Solid-State Flexible Supercapacitors

MXenes are normally used for energy storage applications. However, large nanosheets and restacking are detrimental to the ion diffusion and thus limit its rate capability. Here, a strategy to prepare flexible and porous MXene–M supercapacitor electrodes can simultaneously enlarge the interlayer spacing between layers and create holes in the layers. As a result, Ti3C2Tx–Mn presents an excellent lifespan, with still 248 F g–1after 100 000 cycles at a current density of 100 A g–1. Moreover, Ti3C2Tx–Mn-based symmetric all-solid-state supercapacitor exhibits outstanding volumetric energy up to 52.4 mWh cm–3and retains 38.4 mWh cm–3at an ultrahigh volumetric power density of 55.3 W cm–3. We believe this work provides an idea for the later regulation of MXene layer spacing and the design of porous structures, and can be widely used in the next-generation high-energy density and power density practical applications.