<p>Supercapacitors are attracting attention as next-generation energy storage devices due to their high power density, fast charging and discharging speed, and excellent cyclical stability; however, their low energy density remains a major limitation to commercialization. This study reviews the latest research trends of Ni-based Ni<i>M</i>₂O₄ (M = Co, Mo, Mn, Fe) Spinel-type materials as a promising electrode material to address this problem. The NiM₂O₄ Spinel structure provides abundant redox active sites and multiple oxidation states, exhibiting superior electrochemical activity over single metal oxides. We evaluate the unique characteristics and limitations of NiCo₂O₄, NiMn₂O₄, NiFe₂O₄, and NiMoO₄, highlighting recent engineering strategies to mitigate these challenges. These include nanostructural tailoring to expand surface area, heteroatom doping and defect engineering to enhance conductivity, and the construction of carbon-based composites to improve structural stability. Finally, we outline the key challenges hindering the commercialization of Ni<i>M</i>₂O₄-based electrodes and propose research directions to maximize the performance of next-generation energy storage systems.</p>