Carbon layer-confined MoS 2 /Ni 3 S 2 heterostructure with enhanced sodium and potassium storage performance

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-06, Vol.11 (23), p.12102-12113
• Main Authors: Bai, Jin, Si, Jianguo, Mao, Yunjie, Ma, Hongyang, Wang, Peiyao, Li, Wanyun, Xiao, Ke, Zhang, Guofeng, Wei, Yiyong, Zhu, Xuebin, Zhao, Bangchuan, Sun, Yuping
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA01792C

Transitional metal sulfides have received widespread attention as efficient anode materials for sodium-/potassium-ion batteries (SIBs/PIBs), benefitting from their high theoretical capacities and strong structural reversibility. Nevertheless, their poor electrical conductivity and severe volume variation result in unsatisfactory performance, seriously hindering their practical applications. Herein, a robust carbon layer-confined MoS 2 /Ni 3 S 2 heterostructure (MoS 2 /Ni 3 S 2 @C) was designed and synthesized by a facile one-step hydrothermal method with a subsequent sulfidation process. The Ni 3 S 2 ultrafine nanoparticles are embedded between ultrathin MoS 2 nanosheets, which are surrounded by a thin carbon layer. When used as an anode material for SIBs and PIBs, the heterostructure displays high specific capacities, excellent cycling stability and outstanding rate capability. The superior performance results from the elaborate heterostructure, which forms numerous heterointerfaces, provides more Na + /K + storage sites, shortens the Na + /K + diffusion path and accelerates the charge transfer. Moreover, the carbon layer confinement further promotes the electrical conductivity, enhances the reaction kinetics and accommodates the volume expansion of the heterostructure. The sodium/potassium reaction mechanism and the performance enhancement origin of MoS 2 /Ni 3 S 2 @C were verified by kinetic analyses, multiple ex situ characterizations and density functional theory (DFT) calculations. The carbon layer-confined heterostructure strategy could shed light on the rational design of bimetallic sulfides for high-performance SIBs/PIBs.