Influence of aqueous solutions treatment on the Li+ storage properties of molten salt derived Ti3C2Clx MXene
Pengcheng Liu, Bin Guan, Ming Lu, Hui Wang, Zifeng Lin
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.