Calcination-Induced Structural Evolution of Nickel Phosphate and Its Impact on Charge-Storage Kinetics
DOI:
https://doi.org/10.66514/ssst34-2-165-175Keywords:
Amorphous, calcination temperature, Electrode, Nickel phospahte, SupercapatteryAbstract
Supercapattery performance is governed by the intrinsic properties of its electrode materials, particularly the relationship between microstructure and electrochemical behaviour. In a previous study, amorphous nickel phosphate (NP) has shown superior electrochemical performance as a battery-type electrode despite the common expectation that crystalline materials perform better in electrochemical response. In this work, NP was synthesized via a sonochemical route and its crystallinity was modulated by varying calcination temperatures. At lower calcination temperatures (300–600 ºC), NPs remain predominantly amorphous but turn crystalline when higher temperatures are applied. The thermal treatment also influenced the degree of hydration, particle morphology and pore structure. Among all temperatures, NP calcined at lower temperatures delivered the higher specific capacity and showed predominantly diffusion-influenced Faradaic kinetics. In contrast, NP calcined at higher temperatures showed lower specific capacity, but a stronger surface-control contribution to charge storage. These findings demonstrate that a high degree of crystallinity does not necessarily guarantee high charge-storage capacity and reveal a clear trade-off between active-site utilization and reaction kinetics during the amorphous to crystalline evolution of NP.
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Copyright (c) 2026 Fatin Saiha Omar, Alia Rosli, Aisyah Azizi, Artiqah Khairudin (Author)
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