Yuvarajan Devarajan, Ravikumar Jayabal, Kajal Thakuriya, Shahazad Ali, Beemkumar Nagappan, Devarshi Parsottambhai Tadvi, Yuvaraja Naik, Premananda Pradhan, Kulmani Mehar
The rapid expansion of variable renewable energy necessitates flexible, low-carbon, and long-duration energy storage to maintain grid stability and energy security. Hydrogen has emerged as a pivotal energy vector due to its high gravimetric energy density, chemical versatility, and compatibility with sector-coupled energy infrastructures. This review presents a chemistry-centric perspective on hydrogen-based energy systems, encompassing production pathways, storage strategies, conversion technologies, and integrated energy frameworks. Particular emphasis is placed on electrochemical and thermochemical hydrogen generation, advanced catalytic and storage materials, and the physicochemical principles governing hydrogen conversion to electricity, heat, and synthetic fuels. Recent progress in electrolyzer designs, fuel cell architectures, and hydrogen carrier systems is critically analyzed alongside key challenges involving efficiency, durability, scalability, and lifecycle sustainability. Collectively, the insights highlight hydrogen’s transformative potential to enable resilient, decarbonized energy systems aligned with global sustainability targets, including affordable and clean energy, sustainable industrial innovation, and climate action.