In-situ construction of heterogeneous structure by crystal phase evolution to improve the sodium storage performance of NiCo2O4

• Published in: Journal of alloys and compounds Vol. 1010; p. 177584
• Main Authors: Wang, Qingwei, Yang, Fengxiang, Zhao, Yang, Wang, Jiaheng, Wu, Songyuan, Zhong, Linzhi, Li, Jiarui, Jing, Xiao, Gong, Jiaxu, Dai, Yatang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.01.2025
• Subjects: Cycling stability; Grain boundary; Heterostructure; sodium-ion batteries; strain engineering; Heterostructure; Cycling stability; strain engineering; sodium-ion batteries; Grain boundary
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.177584

Transition metal oxides (TMCs) have great potential in sodium ion batteries (SIBs) due to their significantly higher capacity and lower cost. However, during the cycle, huge volume changes often lead to structural damage, which is a key factor in the rapid decay of capacity. In this paper, a heterogeneous structure was constructed in situ by introducing sulfur element to induce the decomposition of NiCo2O4 crystal phase. The rich heterogeneous interface has enhanced redox reaction kinetics and charge transport properties. For high-capacity conversion anode materials, cross-linked grain boundaries can effectively disperse the local stress caused by volume changes and alleviate the inevitable electrode crushing, thus ensuring the stability of the electrode during long-term cycling. The NiCo2O4/NiCo2S4/CoO/ NiO heterogeneous structure (NCOS-350) exhibits enhanced cycling and rate performance (350 mAh g−1 at 0.5 A g −1 after 100 cycles and 270 mAh g −1 at 5 A g −1) when used as the anode for sodium ion batteries. In addition, it is proved that NCOS-350 has smaller volume change and better structural stability than NiCo2O4 by scanning electron microscopy and other characterizations. •Sulfur doping induces the decomposition of NiCo2O4 crystal phase.•A heterogeneous structure of NiCo2O4/NiCo2S4/CoO/NiO was constructed.•NiCo2O4/NiCo2S4/CoO/NiO exhibits excellent structural stability during cycling.