Recently, the research team from the School of Physics and Optoelectronics at South China University of Technology reported their findings on using layered vanadium-based oxides as novel cathode materials for aqueous nickel-ion batteries. The research was published in the journal Energy Storage Materials.
Nickel-metal anodes in aqueous nickel-ion batteries are notable for their high capacity density, smaller ionic radius, and resistance to dendrite formation, making these batteries stand out among multivalent ion batteries. However, nickel ions have a high charge density, which results in strong electrostatic interactions with the cathode materials, leading to slow nickel ion diffusion dynamics. The lack of suitable cathode materials, combined with unclear storage mechanisms and diffusion pathways for nickel ions, has significantly hindered the development and application of aqueous nickel-ion batteries.
To address this issue, the research team innovatively designed a "dual-layered divanadium pentoxide pre-intercalated with iron ions" as the cathode material for aqueous nickel-ion batteries. This material expands the interlayer spacing, providing a rapid diffusion channel for nickel ions. The pre-intercalated iron ions act as pillars between the layers, significantly enhancing the structural stability of divanadium pentoxide. Further composite with graphene effectively improves the electrical conductivity of the electrode material.
This cathode material demonstrated high reversible capacity and exceptional cycle life in aqueous nickel-ion batteries. The research team used a variety of characterization methods, including in-situ X-ray diffraction, ex-situ Raman spectroscopy, and X-ray photoelectron spectroscopy, along with first-principles calculations, to deeply investigate the charging and discharging mechanisms of aqueous nickel ions and to reveal the diffusion pathways of nickel ions in the cathode material, analyzing the electrochemical kinetics of the system.
This work is of significant importance for the development and mechanism research of aqueous nickel-ion batteries and their cathode materials.
Related paper information: https://doi.org/10.1016/j.ensm.2024.103340
