Transition metal oxide-based electrode materials for flexible supercapacitors: A review

Highlights: • Different types of TMOs applied for flexible supercapacitors are studied. • Fabrication of TMOs-based electrode for flexible device, are thoroughly discussed. • The challenges and landscape of TMO-based flexible supercapacitors are highlighted. • Recent advances of TMOs -based flexible supercapacitors are reviewed. -- Abstract: All over the world, the research done on designing the novel methods for inventing flexible electrochemical energy storage devices is becoming of more interest each day while the development of new technology in fields such as public wearable, consuming portable electronics, and electronic skin proceeds. Taking their large power density, cyclic stability, and outstanding mechanical integrity completeness into account, flexible supercapacitors are being used as energy storage devices at a wide interval. In the past few years, researchers have devoted considerable energy to promoting different kinds of transition metal oxides (TMOs) to employ in supercapacitors. Their choice can be found in unique TMOs characteristics such as ideal capacitive performance, low cost, and environment friendly. Their charge storage mechanisms obey from pseudocapacitance behavior. In the present document, we aim to provide a brief collection of the latest outcomes about several electrode materials of flexible supercapacitors based on TMOs and present this review by categories. The most popular routes to produce TMOs-based electrode materials, and the typical fabrication techniques for flexible devices, are thoroughly discussed. To add, since there is a tight connection between the morphology of the electrode materials and the electrochemical performance, the evaluation of the electrode component effect on the mechanical flexibility of the fabricated devices is a necessity. Not far ago for making accurate predictions about the upcoming trends towards the comprehension of an ultimate-performance, TMOs-based flexible supercapacitors, a history of the throughout electrochemical nobles and current evolution of the reported devices has been reported.