Recent Progress for Sodium/potassium Hybrid Capacitors
Metal ion hybrid capacitors (MIHCs) have been recognized as one of the most promising power sources owing to their combined merits of high energy density in battery and high power output in supercapacitor. The kinetics mismatch between capacitor-type cathode and battery-type anode yet must be well addressed befroe implementing their practical feasibility. Here, we overview the recent progress on sodium and potassium ion hybrid capacitors (SIHCs, PIHCs) and discuss the major challenges and outlook the future directions in this field. The fundamental knowledge and the history will be firstly introduced, special emphasis are then laid on the develoement of a variety of electrode materials in the recent years. The prospective to the future research of MIHCs is finally proposed towards their practical applications. We wish the feature article can not only educate the new commers starting their reasearch in this field, but also inspire the experieced researchers to contribute to the development of high-performance MIHCs devices.