Abstract
Energy storage devices are some of the most important environmental technologies that are highly influential in advancing our life in the future society. Specifically, electrochemical capacitor is an energy facilitator that exhibits an efficient/economical charging and discharging characteristics with long lifespan. Thus, the capacitor technology is regarded as promising due to an increasing effectiveness when combined with renewable (solar/wind/micro hydraulic) energy sources. In this connection, Li–ion-based hybrid supercapacitors and their functional materials are being vigorously researched in hopes to improve their capacity/voltage and therefore their energy density. Transition metal oxides are among the most popular materials utilized in this purpose. Thanks to high voltage and associated high energy density, they are tuned as both high energy and high power materials. In recent years, the structural/textural properties of oxides, including particle size, crystallinity, defects, and porosity, were successfully fine-tuned to achieve high rate performance over 300 C . The present review will describe pseudo-capacitive nanosized oxides prepared with in situ synthesis technique called “ultracentrifugation”, showing ultrafast electrochemical response even more than EDLC.