Energy Release from RuO2//RuO2 Supercapacitors under Dynamic Discharge Conditions

Abstract In this study, RuO2 was deposited on tantalum (Ta) substrates by electrochemical plating and then assembled into supercapacitors RuO2//RuO2. The output energies of the as-obtained RuO2//RuO2 under dynamic conditions were evaluated through a designed measuring circuit. The specific capacitance of electrodes in RuO2//RuO2 was calculated from the experimental results of the discharge current and the potential of positive/negative electrodes during discharge. Also, the energy of the positive/negative electrodes and RuO2//RuO2 with respect to time were derived. The results showed the positive electrode energy was partly transferred into the load R to generate joule heat and the other was used to elevate the potential of the negative electrode during discharge. The decrease in mass of negative electrode ( m − ) could extend the potential window, resulting in an enhancement of the energy of RuO2//RuO2. The energy of RuO2//RuO2 with m − = 103 μ g was elevated by 138.7% compared to that with m − = 200 μ g . Further decrease in mass of the negative electrode would deteriorate the energy of RuO2//RuO2.