Electrochemical characterization on layered lithium ruthenate for electrochemical supercapacitors

Electrochemical characteristics of lithium ruthenate (LixRuO2+0.5x·nH2O) for electrochemical capacitorsʹ electrode material were first examined in this paper by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests. Results show that LixRuO2+0.5x·nH2O has electrochemical capacitive characteristic within the potential range of − 0.2–0.9 V (vs. SCE) in 1 M Li2SO4 solution. The capacitance mainly arises from pseudo-capacitance caused by lithium ionsʹ insertion/extraction into/out of the LixRuO2+0.5x·nH2O electrode. The specific capacitance of 391 F g− 1 can be delivered at 1 mA charge–discharge current for LixRuO2+0.5x·nH2O electrode with an energy density of 65.7 W h kg− 1. This material also exhibits an excellent cycling performance and there is no attenuation of capacitance over 600 cycles.