Effect of electrode balance on performance degradation and gas emission in stacked-type electrochemical capacitors

For electrochemical capacitor, the specific capacitance in positive is not equal to negative because of different sizes between cation and anion such as TEABF₄/PC. In stacked-type of electrochemical capacitor, the optimized stacked-type cell generates gas 25% lower than current stacked-type cell. Our results show that H₂ gas emitted from current stacked-type is twice that from optimized stacked-type; the proportion of CO in current stacked-type is similar to optimized stacked-type, while that of CO₂ in optimized stacked-type is 73% of that in current stacked-type. The working voltages of the current stacked-type capacitor and optimized stacked-type are expected to be around 3.3V and below 3.0V, respectively, because the amount of gas emissions from optimized stacked-type is estimated to be 30% less than that from current stacked-type. And higher reliability is shown in optimized stacked-type with alkali activated carbon in positive and steam activation carbon in negative. The generated gas volume by optimized stacked-type with different carbon is decreased around 50% than current stacked-type electrochemical capacitor.