Influence of aqueous solutions treatment on the Li+ storage properties of molten salt derived Ti3C2Clx MXene

Abstract

Molten salt (MS) derived MXenes have been reported with outstanding pseudocapacitive Li+ storage performance due to the unique chlorides and -O surface groups. In this work, we investigate the influence of Li+ storage properties of Ti3C2Clx MXene treated with different aqueous solutions (including H2O, 0.5 M H2SO4, 0.5 M NaOH, and 0.5 M ammonium persulfate (APS)) washing. Maximum specific capacities of Ti3C2Clx-H2O, Ti3C2Clx-H2SO4, Ti3C2Clx-NaOH, and Ti3C2Clx-APS are 137, 140, 103, and 204 mAh g−1, respectively. It is concluded that the APS treatment will increase the -O termination content, leading to enhanced lithium-ion storage capacity. Differently, NaOH treatment results in the partial conversion of Ti3C2Clx into TiO2, thus deteriorating the lithium-ion storage capacity. This work highlights the significant effect of aqueous solution washing on the Li+ storage properties of Ti3C2Clx MXene.

Keywords

• MXene
• Molten salt synthesis
• Li+ storage
• Aqueous solutions treatment