Tailoring NH₄⁺/H⁺ Co-adsorption Chemistry into h-Ti₃C₂ MXene for High Load Aqueous Microsupercapacitors

Aqueous microsupercapacitors (AMSCs) with safe and low-cost are anticipated as a leading choice for micro energy storage devices. Nevertheless, the current issue with AMSCs is their extremely low area energy density and power density, which is caused by a strong interaction between metal ions as well as the stacking properties of thick electrodes. Herein, we develop AMSCs based on the tailoring mechanism of NH 4 + /H + co-adsorption into hydroxylated Ti 3 C 2 MXene (h-Ti 3 C 2 MXene). This co-adsorption mechanism enhances the adsorption kinetics of electrode materials. The ultra-high-load h-Ti 3 C 2 MXene with a carpet shape and more oxygen-containing functional groups further improves the low performance of the thick electrode. As a result, the reported AMSCs exhibit impressive power density (16.50 mW cm –2 at 110.91 μWh cm –2 ), energy density (394.59 μWh cm –2 at 0.825 mW cm –2 ), and cycle life (20 000 GCD cycles retain 92.45%). This work provides an entirely new tailoring NH 4 + /H + co-adsorption mechanism for building advanced AMSCs.