Electrochemical capacitors utilising transition metal oxides: an update of recent developments

Abstract

Transition metal oxides receive considerable attention in the area of electrochemistry not only due to their beneficial reported structural, mechanical or electronic properties, but because of their capacitive properties ascribed to their multiple oxide states they exhibit pseudo capacitances which carbon counterparts generally cannot. Typically transition metal oxides may be classified as noble transition metal oxides which exhibit excellent capacitive properties but have the drawback of generally being relatively expensive. Alternatively base metal oxides may also be utilised which are considerably cheaper and more environment friendly than noble transition metals as well as exhibiting good capacitive properties. In considering that nanostructured materials can help ameliorate the electrochemical performances of transition metal oxides, this review summarizes the recent investigations of fundamental advances in understanding the electrochemical reactivity of transition metal oxides, thus leading to an improved capacitive performance, which is essential for their continual use in a plethora of supercapacitor applications.

Titanium Dioxide Nanotube Films for Electrochemical Supercapacitors: Biocompatibility and Operation in an Electrolyte Based on a Physiological Fluid

“…1,[7][8][9][10] TiO 2 is an interesting electrode materials for the state-of-the-art electrochemical energy storage systems and can be used both lithiumion batteries 11-13 and electrochemical supercapacitors. 12 Films of TiO 2 nanotube arrays have particularly attracted attentions for the application in supercpacitors because of their high surface area and have been a subject of a number of studies.…”

Nickel/Iron Oxide Nanocrystals with a Nonequilibrium Phase: Controlling Size, Shape, and Composition

“…Metal oxides and mixed metal oxides (MMOs) are of significant interest as electrode materials in a broad range of device applications, including Li-ion batteries, 1−3 electrochemical capacitors, 2,4,5 fuel cells, 6,7 gas sensors, 8,9 thin film transistors 10−12 and electrochemical water oxidation catalysts. 13−16 Many synthetic methods have been reported for the production of high-purity MMOs, including the mechanical mixing of metal precursors, 17−19 spray pyrolysis, 20,21 sol−gel decomposition, 11,22−24 hydrothermal processing, 24−27 polymerbased processes, 28,29 and solution-phase thermal decomposition of metal−organic precursors.…”

Nitrogen/manganese oxides co-doped nanoporous carbon materials: Structure characterization and electrochemical performances for supercapacitor applications

“…An alternative method to enhance the capacitance is to incorporate additional contributions from pseudo-capacitance [10]. In terms of transition metal oxides possessing mixed valences such as MnO 2 , NiO, Fe 3 O 4 , Co 3 O 4 , they have been demonstrated for supercapacitor application due to the superior pseudo-capacitive behavior, practical availability, environmental compatibility and lower cost especially in contrast to the expensive and rare material RuO 2 [11]. Among these metal oxides, manganese oxides, basically including MnO, Mn 3 O 4 , Mn 2 O 3 , MnO 2 with different allotropes, exhibit the advantages of low cost, no toxicity, easy to obtain and high specific capacitances and therefore has been taken for granted as the most promising materials in application of supercapacitors [12].…”