Strategic Expedition of Ni to Design High-Performance Material for Advanced Energy Storage and Conversion Applications

Roy, Avishek (2026) Strategic Expedition of Ni to Design High-Performance Material for Advanced Energy Storage and Conversion Applications. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Avishek Roy (20RS138)) 20RS138.pdf - Submitted Version Restricted to Repository staff only Download (25MB)

Abstract

Focusing on the demographic growth of the global population and surging depletion of non-renewable feedstocks, the modern energy technologies quest for sustainable and paradigm resolutions. Especially worldwide, tremendous emphasis has been placed on developing cutting-edge materials to advance both energy storage and conversion applications. In the domain of energy conversion, electrocatalytic water splitting offers a transformative and compelling pathway for producing green hydrogen as a clean energy source, with a thermodynamic onset potential of 1.23 V vs. RHE. Pt group of metals reigns as the leading candidates for H₂ production; their scarcity drives the need to cultivate their proper alternative. Further, due to the additional energy consumption in the Volmer step, the hydrogen evolution reaction (HER) in an alkaline medium imposes a substantial scientific challenge. On the other hand, the extent of HER depends on the protons and electrons from the anodic oxygen evolution reaction (OER), which is kinetically sluggish due to a complex 4e- transfer process, resulting in a notably high overpotential. In this context, small-molecule (urea, alcohol, hydrazine, amine, sulfonate) oxidation facilitates H2 production and the formation of valuable by-products. Hence, the pursuit of designing an earth-robust transition-metal-based electrocatalyst is a global imperative. Further, redirecting the focus to energy storage systems, batteries, and supercapacitors are undisputed powerhouses propelling our consumer electronics tech every day. In particular, batteries excel at delivering high energy density but suffer from poor specific power and quick fade over the cycle life. In stark contrast, supercapacitors deliver immense power density and can withstand prolonged cycling, yet they are constrained by their lower energy density. In this context, battery-type supercapacitors are emerging due to their optimal power and moderate energy output. Further, when constructing a hybrid device, the battery-type materials provide a higher operating voltage. However, due to continuous phase change, the materials result in a degraded cycle life. Thus, to advance the energy-storage sectors, developing a robust battery-type material with high specific capacitance is a paramount interest. Finally, designing a unified material that bridges both supercapacitive energy storage and H₂-fuel-assisted conversion technology is a critical scientific pursuit. Nonetheless, due to kinetic constraints and distinct reaction mechanisms, designing such materials is a distinctly challenging endeavor. In this context, nickel-based materials are advantageous due to their oxyphilic character, ease of oxidation-state shift, and low cost. Ni-based systems are stable under harsh alkaline conditions, providing optimal support for the Volmer step and reducing energy consumption during hydrogen evolution. Considering energy-efficient small-molecule (urea, alcohol, hydrazine, amine, sulfion) oxidation-assisted H₂ production, the Ni(III) state serves as the active centre. Furthermore, Ni-based materials are leading as battery-type supercapacitance due to their dominant diffusion-controlled nature and high redox behaviour, but suffer from poor cyclic stability. Inspired by preceding scientific hurdles, we strategically expedite the Ni-systems to design high-performance material for advanced electrocatalytic energy conversion and supercapacitive charge storage devices.

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