<p>Supercapacitors (SCs) are crucial in today's environment to meet the growing need for energy. To improve the performance of metal oxide-based SCs, electrode materials with strong electrocapacitive properties must be designed. A significant number of studies have been published recently about the fabrication of electrode materials using different synthesis methods for SCs. This paper provides a fundamental, comprehensive review of recent advancements in SCs. Compared to single-component metal oxides, ternary metal oxides (TMOs) exhibit multiple oxidation states and superior supercapacitive performance due to synergistic effects. The synthesis methods and electrode materials for TMOs in SC applications are reviewed in this study. A basic understanding of synthesis methods and choice of electrode materials for TMOs is reported, which will help to develop better electrode materials for SCs. This study also suggests future perspectives for the development of high-performance energy storage devices for SC applications.</p> Graphical Abstract <p></p>