Covalent Organic Frameworks (COFs)/MXenes Heterostructures for Electrochemical Energy Storage

Covalent organic frameworks (COFs), a distinguished class of porous materials exhibiting precise modularity and crystallinity, and two-dimensional (2D) MXenes, a highly conductive, atomic layered transition metal carbides or nitrides or carbonitrides, are the two fascinating classes of advanced materials that have been intensively researched for energy storage recently. Thanks to the high surface area and porosity of COFs and high electrical conductivity coupled with highly redox active surfaces of MXenes, they have shown great potential in the energy storage applications such as batteries and supercapacitors. However, their electrochemical performance is limited by several inherent issues such as the restacking tendency of MXene sheets and low conductivity of COFs, when applied individually. Combining MXenes and COFs into heterostructures and their use as a single electrode helps in overcoming challenges for improving the energy storage capability. The current perspective intends to provide an overview of designing such COF/MXene heterostructures in the context of the energy storage applications. The research gaps that exist in designing COF/MXene heterostructures and the governing factors for improving the energy storage capability have also been highlighted as opportunities.