How to achieve high mass loadings while maintaining energy and power densities together with slow self-discharge rates for aqueous asymmetric supercapacitors (AASCs) remains a great challenge. Herein, we tested an AASC using Ti3C2Tz MXene as the negative electrode, mixture of manganese oxides, Mn3O4 MnOOH, positive electrode saturated lithium chloride (14 M LiCl) electrolyte. This device, thick...