Compositing MXenes with hierarchical ZIF-67/cobalt hydroxide via controllable in situ etching for a high-performance supercapacitor

Abstract

In this study, hierarchical MXene@ZIF-67/core–shell/yolk–shell cobalt hydroxide (MXene@CS-ZCH/MXene@YS-ZCH) and MXene@hollow cobalt hydroxide (MXene@Ho-CH) composites were prepared via the in situ gradient etching of a cubic ZIF-67 loaded MXene. The interlayer hierarchical cobalt hydroxide nanostructures ensure efficient electron transfer and the three-dimensional (3D) configurations avoid the accumulation/self-aggregation of two-dimensional (2D) layered materials. Meanwhile, the MXene can significantly improve electron transfer as a conductive substrate. The MXene@Ho-CH electrode shows excellent rate performance and cycling stability. This work provides a strategy for achieving MXene compositing with hierarchical core–shell/yolk–shell/hollow (CS/YS/Ho) structured MOF derivatives for electrochemical energy storage.