3D Heterostructure Constructed by Few-Layered MXenes with a MoS2 Layer as the Shielding Shell for Excellent Hybrid Capacitive Deionization and Enhanced Structural Stability

作者：Yanmeng Cai, Yue Wang, Le Zhang, Rongli Fang, Jixiao Wang · 发表于：ACS Applied Materials & Interfaces · 年份：2022 · DOI：10.1021/acsami.1c20531 · 被引用次数：127 · 研究领域：Membrane-based Ion Separation Techniques、Membrane Separation Technologies、Supercapacitor Materials and Fabrication

Two-dimensional (2D) layered transition-metal carbides (MXenes) are attractive faradic materials for an efficient capacitive deionization (CDI) process owing to their high capacitance, excellent conductivity, and remarkable ion storage capacity. However, the easy restacking property and spontaneous oxidation in solution by the dissolved oxygen of MXenes greatly restrict their further application in the CDI domain. Herein, a three-dimensional (3D) heterostructure (MoS 2 @MXene) is rationally designed and constructed, integrating the collective advantages of MXene flakes and MoS 2 nanosheets through the hydrothermal method. In such a design, the well-dispersed MXene flakes can effectively reduce the aggregation of MoS 2 nanosheets, boost electrical conductivity, and provide efficient charge transfer paths. Furthermore, MoS 2 nanosheets as the high-capacity interlayer spacer can prevent the self-restacking of MXene flakes and provide more active sites for ion intercalation. Meanwhile, the strong chemical interactions between MXene flakes and MoS 2 nanosheets contribute to accelerating the charge transfer kinetics and enhancing structural stability. Consequently, the resulting MoS 2 @MXene heterostructure electrode possesses high specific capacitance (171.4 F g –1 ), fast charge transfer and permeation rate, abundant Na + diffusion channels, and superior electrochemical stability. Moreover, the hybrid CDI cell (AC//MoS 2 @MXene) with AC as the anode and MoS 2 @MXene as the cathod...