Current research on transition metal oxide materials used to improve super-capacitor performance
Haider M. Umran, Ahmed A. Alibage
Abstract
Increased energy consumption from traditional energy sources has resulted in increased pollution, which has become a serious threat to human life and living conditions. The development of renewable, reliable, and inexpensive energy storage devices has thus become both an urgent practical issue and an important research topic in modern society. New energy storage technologies, including the development of Super-Capacitors (SCs) with high energy density, cycle stability, and rapid charge/discharge processes, play a vital role in accelerating the innovation and development of such storage devices, making them among the most important and promising new energy components. Transition metal oxides (TMOs) have received significant attention in this regard because of their higher specific capacitance, which has already been used to enhance the electrical conductivity and electrochemical performance of SCs. This work thus focuses on a review of the use of ruthenium oxide (RuO2), manganese oxide (MnO2), iridium (IV) oxide (IrO2), cobalt oxide (Co3O4), and nickel oxide (NiO), which are among the most widely used TMOs, in capacitor electrodes. Various preparation methods for TMOs are presented, and some of their disadvantages, including low electrical conductivity and weak cycle stability, discussed alongside a review of the electrochemical properties of some mixed TMOs and their composites with various highly conductive carbon nanomaterials.