Engineered Molybdenum Disulfide-based Nanomaterials for Capacitive Deionization Application

Capacitive deionization (CDI) is a highly promising technique for removal ions from water, showing great perspective in desalination of salty water and wastewater remediation. CDI displays an energy efficiency, simple operation, excellent reversibility, long-term stability, and high feasibility for coupling with other techniques. Similar to supercapacitors, the electrode materials play crucial role in determining CDI performance, such as operating voltage, desalination capacity, and the lifecycle of CDI cells. Molybdenum disulfide (MoS2), a typical two-dimensional (2D) metal sulfide, has gained tremendous attention in CDI technique due to its exceptional mechanical, electrical, and optical properties. Herein, we critically reported deliberated the inventory and the recent progress in the rational design of MoS2 based electrodes for CDI cells. We start with a brief introduction to foundation knowledge of CDI system and structure of MoS2. To make the review comprehensive, we then summarized the available common techniques to prepare MoS2 based nanomaterials, spanning from various exfoliation processes, chemical vapor deposition, colloidal synthesis, hydrothermal/solvothermal synthesis, and molten salt synthesis. Significantly, the recent progress of MoS2 based electrodes in CDI application is summarized in detail. These systems are divided into pristine MoS2 and various MoS2 based composite with other species, such as carbon, conducting polymer, metal oxide, MXene, and C3N4. For assisting further development of MoS2 electrodes for efficient and long-term stable CDI, some challenges and possible solutions are outlined.