A Minireview of Multimetallic Iron-Based Oxides for Supercapacitive Negative Electrode Materials

The serious mismatch between the positive and negative electrodes of supercapacitors (SCs) makes it imperative to develop high-performance negative electrode materials. Among them, multimetallic iron-based oxides (MIBOs) are intensively investigated attributed to their high theoretical specific capacitance, wide operating potential window, copious electrochemical active sites, variable metal oxidation states, and abundant redox centers. This paper briefly introduces some essential information on SCs and the most common synthesis methods of MIBOs. Also, the research progress of several important MIBOs and their composites is discussed. Finally, the existing problems and challenges of MIBOs are summarized and future outlooks are likewise proposed.