Recent Advancements of Spinel Oxide Materials in Energy and Fuel Applications

In recent years, spinel oxides (i.e., AB₂O₄) have gained attention for energy and fuel applications due to their inherent structural stability and unique functional properties, making them strong contenders for advancing different energy systems. The intrinsic structural flexibility of AB₂O₄ permits targeted modification of their electrical, magnetic, chemical, thermal, and structural characteristics to meet various operational requirements. This review focuses on recent research (from 2020 to the present) on how such a big family of materials can be tailored and leveraged for use in energy and fuel applications, such as batteries, supercapacitors, fuel cells, electrolysis, CO₂ conversion, and chemical catalysts. We focus on experimental strategies for modifying spinels to better exploit their key attributes while minimizing known drawbacks. This review aims to evaluate the use of key modification approaches to tune the structures and properties of AB₂O₄, including doping, defect engineering, and nanostructuring, to drive improvements in energy and fuel applications. Additionally, we discuss diverse emerging applications where continued innovation could significantly enhance the role of spinels in advanced energy systems.