Progress of electrochemical capacitor electrode materials: A review

The electrode is the key part of the electrochemical capacitors (ECs), so the electrode materials are the most important factors to determine the properties of ECs. In this paper, the storage principles and characteristics of electrode materials, including carbon-based materials, transition metal oxides and conductive polymers for ECs are depicted briefly. Among them, more work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and organic electrolytes. But the composites of pseudocapacitive and carbonaceous materials are promising electrode materials for ECs because of their good electrical conductivity, low cost and high mass density.