Synthesis of Low-Crystalline MnO 2 /MXene Composites for Capacitive Deionization with Efficient Desalination Capacity.

MXene has drawn widespread attention as a potential material for electrode use in capacitive deionization (CDI). However, the applications of MXene are limited by its property of low electrical capacity. Herein, a MnO₂/MXene composite was firstly evaluated in a capacitive deionization system, in which the MnO₂ acts as intercalation-type pseudocapacitive electrodes to enhance the electrical capacity, and MXene provides an electron conduction highway network that improves the charge transfer of the MnO₂. The result showed that the low-crystallinity MnO₂ with irregular particles was well-distributed on the surface of the MXene. The desalination capacity of 30.5 mg·g⁻¹ is achieved at a voltage window of 1.2 V, which was higher than that of the reported pure MXene and MnO₂. The electrical double-layer (EDL) capacitive and the diffusion-controlled processes are the main charge storage mechanisms, and the EDL contribution provides 50.3% to the total capacitance. This result suggests a promising direction for further applying a MnO₂/MXene composite in CDI. [ABSTRACT FROM AUTHOR]