Xue Fangfang, Fan Feifan, Zhu Zhicheng, Zhang Zhigang, Gu Yuefeng, Li Qiuhong
Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, China.
School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China.
Nanoscale. 2023 Apr 6;15(14):6822-6829. doi: 10.1039/d3nr00866e.
Heterostructure construction with mixed transition metal sulfides has been recognized as a promising strategy to boost the performance of sodium-ion batteries (SIBs). Herein, a carbon-decorated MoS/CoS heterostructure on carbon cloth (MoS/CoS@CC) as a free-standing anode for SIBs was synthesized a facile growth-carbonization strategy. In the composite, the generated built-in electric field at MoS and CoS heterointerfaces is beneficial for elevating the electron conductivity, thus expediting the Na-ion transport rate. Moreover, different redox potentials between MoS and CoS can effectively mitigate the mechanical strain induced by repeated Na de-/intercalation, thus ensuring the structural integrity. In addition, the carbon skeleton derived from the carbonization of glucose can enhance the conductivity of the electrode and maintain the structural integrity. Consequently, the resulting MoS/CoS@CC electrode delivers a reversible capacity of 605 mA h g at 0.5 A g after 100 cycles, and prominent rate performance (366 mA h g at 8.0 A g). Theoretical calculations also confirm that the establishment of a MoS/CoS heterojunction can powerfully promote the electron conductivity, thereby enhancing the Na-ion diffusion kinetics.
构建具有混合过渡金属硫化物的异质结构已被认为是提高钠离子电池（SIBs）性能的一种有前景的策略。在此，通过一种简便的生长-碳化策略，在碳布上合成了一种碳修饰的MoS/CoS异质结构（MoS/CoS@CC）作为SIBs的独立阳极。在该复合材料中，MoS和CoS异质界面处产生的内建电场有利于提高电子电导率，从而加快钠离子传输速率。此外，MoS和CoS之间不同的氧化还原电位可以有效减轻由反复的钠脱嵌所引起的机械应变，从而确保结构完整性。此外，由葡萄糖碳化衍生的碳骨架可以提高电极的电导率并保持结构完整性。因此，所得的MoS/CoS@CC电极在0.5 A g下循环100次后具有605 mA h g的可逆容量，以及出色的倍率性能（在8.0 A g下为366 mA h g）。理论计算也证实，MoS/CoS异质结的建立可以有力地促进电子电导率，从而增强钠离子扩散动力学。
