Impact of Aging Regime and State of Charge on Self-Discharge of Hybrid Supercapacitors
This study focuses on investigating the factors affecting the self-discharge and K-value of hybrid supercapacitors(HSCs)with activated carbon and lithium metal oxide as positive electrode materials and high-rate carbon material as the negative electrode material.By simultaneously enabling lithium-ion storage and double-layer energy storage in an electrolyte cell,HSCs utilize multiple monomers connected in series and parallel to enhance voltage and energy.The aim of this research is to explore the impact of different aging regimes,including aging temperature,time,and voltage,as well as the state of charge(SOC),on the self-discharge and K-value of HSCs.The findings reveal that higher aging temperatures contribute to improved K-value stability,while having minimal influence on self-discharge.Longer aging times result in smaller K-values,and a 72-hour aging time is suggested for effective monomer selection considering energy efficiency.Aging voltage significantly affects self-discharge and K-value,with lower aging voltages leading to poorer self-discharge but higher K-values,and higher aging voltages promoting self-discharge and K-value stability.Moreover,different SOC levels also have a significant impact,with a slight increase in voltage during standby at SOC levels below 3.0 V and negative K-values.However,when the voltage exceeds 3.0 V,the voltage gradually decreases with longer standby time,stabilizing at approximately 0.2 mV·h-1 after 48 hours of standby under 3.8V conditioning.
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