Abstract:

Tungsten disulfide (WS₂), as a typical two-dimensional transition metal sulfide with a wide layer spacing (6.2Å，1Å=0.1nm) and a multi-electron conversion reaction sodium storage mechanism, is a sodium ion battery anode material with high theoretical specific capacity and fast sodium ion reaction kinetics. However, in its actual sodium storage process, the electronic conductivity inherent in the 2H phase structure of WS₂ is poor, and the large phase structure transformation and volume change are brought about by the conversion reaction, as well as the dissolution and shuttle effect of the reduced intermediate product polysulfide (NaS _x, 0<x<2) and the low conductivity of the reduced product sodium sulfide (NaS₂) during the charging and discharging process, leading to the less than ideal actual electrochemical performance of WS₂. To address the above problems, this paper introduced the basic structural features of WS₂, briefly described the main synthetic methods and modifications that existed, and researchers has used hydrothermal/solvent thermal and high-temperature sulfidation methods for nanostructure design, compounding with carbon materials, and introducing a second phase to build a heterogeneous structure to enhance the electrochemical performance of WS₂. Finally, the main modification methods of WS₂ materials and the achieved results are summarized. In the future research direction of WS₂ sodium storage materials, the combination of various modification strategies such as nanostructure design, compounding with carbon materials, constructing heterojunctions, doping with heterophase atoms and increasing active sites to fabricate high magnification performance WS₂ materials that can achieve fast charging and discharging with stable structure is the focus of research.

Key words: tungsten disulfide, sodium-ion batteries, nanostructure, composites, electrochemistry

摘要：

二硫化钨（WS₂）作为一种典型的二维过渡金属硫化物具有宽阔的层间距（6.2Å，1Å=0.1nm）和多电子转化反应储钠机制，是一种具有高理论比容量和快速钠离子反应动力的钠离子电池负极材料。但其在实际储钠过程中，2H相结构的WS₂固有的电子导电性较差，转化反应带来较大的相结构转变和体积变化，以及充放电过程中还原中间产物多硫化钠（NaS _x，0＜x＜2）存在溶解和穿梭效应，还原产物硫化钠（NaS₂）导电性低等问题，导致WS₂的实际电化学性能不太理想。针对上述问题，本文介绍了WS₂的基本结构特征，简述了目前存在的主要合成方法和改性手段，研究者们通过水热/溶剂热和高温硫化等方法来进行纳米结构设计、与碳材料复合和引入第二相构建异质结构以提升WS₂的电化学性能。最后总结了WS₂材料的主要改性手段和已取得的成果，在未来WS₂储钠材料的研究方向中，将纳米结构设计、与碳材料复合、构建异质结、掺杂异相原子和增加活性位点等多种改性策略结合来制造可以实现快速充放电且结构稳定的高倍率性能WS₂材料是研究重点。

关键词: 二硫化钨, 钠离子电池, 纳米结构, 复合材料, 电化学