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

Abstract

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 NH4+/H+ co-adsorption into hydroxylated Ti3C2 MXene (h-Ti3C2 MXene). This co-adsorption mechanism enhances the adsorption kinetics of electrode materials. The ultra-high-load h-Ti3C2 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 NH4+/H+ co-adsorption mechanism for building advanced AMSCs.