Mxene pseudocapacitive electrode material for capacitive deionization

Due to the continually growing world population, water desalination has played a vital role for many countries with a shortage of clean water services. A relevant process for brackish water desalination is capacitive deionization (CDI) with the potential of producing clean water via low energy consumption electrochemical interactions. Due to the recent availability of layered and nanostructured materials to fabricate faradaic electrodes acting as pseudocapacitors to increase the salts' storage capacity, CDI-like desalination methods have gained renewed interest. As a way of improving the desalination performance and energy efficiency of CDI, faradaic deionization (FDI) based on faradaic electrodes such as Ti-MXene (Ti3C2Tx) have been proposed for brackish water desalination. This paper provides a review of the theoretical and experimental framework underpinning CDI and FDI using MXene as electrodes, discussing the actual unique role of MXene in CDI-like desalination methods and its prospects. We will examine MXene's current achievements in the broader area of faradaic and hybrid capacitive deionization if compared with other materials and with various architectures and determine the research gaps in the use of MXene for these applications.