Insight into faradaic mechanism of NiCo-CHH microspheres in high-performance Ni-Cu batteries

• Published in: Scripta materialia Vol. 215; p. 114691
• Main Authors: Dai, Shuge, Zhang, Wang, Xia, Tianyu, Hu, Hao, Zhang, Zhuangfei, Li, Xinjian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2022
• Subjects: Energy storage mechanism; In-situ Raman; Ni-Cu batteries; NiCo-CHH microspheres; In-situ Raman; NiCo-CHH microspheres; Energy storage mechanism; Ni-Cu batteries
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2022.114691

Preintercalation of ions/molecules into the crystal structure with further structural reconstruction can provide fundamental optimizations to improve the electrochemical performance of electrode materials. Herein, Co-doped nickel carbonate hydroxide hybridized (NiCo-CHH) microspheres are prepared by incorporating cobalt cations, carbonate ions and water molecules into the layered-structure of Ni(OH)2. The optimized NiCo-CHH electrode shows ultrahigh specific capacity, superior rate performance and excellent cycling stability. In situ Raman spectroscopy demonstrates that the preintercalation of Co cations, carbonate ions and crystal water molecules into the layered crystal structure of Ni(OH)2 can activate more active sites, improve the electronic conductivity, facilitate diffusion kinetics, and strengthen the crystal structural integrity of Ni(OH)2. Ex situ XRD, ex situ SEM and TEM images reveal the electrochemical reaction mechanism on the anode surface. These findings provide new insight into the faradaic mechanism generally applicable to aqueous rechargeable Ni-Cu batteries. [Display omitted] A novel Ni-Cu cell is assembled from NiCo-CHH microspheres as the cathode and pure Cu foil as the anode, delivering high capacity, superior rate capability and good cycling stability. The charge storage behavior and structural evolution of the NiCo-CHH//Cu cell are carefully understood using in situ Raman spectroscopy.