Study On The Effect Of Electrode Potential On The Performance Of Double-layer Capacitor

Supercapacitors are widely used in industry,electronics and other fields due to their excellent characteristics such as fast charging and discharging speed,high power density and long cycle life.At present,the main research direction of supercapacitors is to improve their energy density.The corresponding measures include changing the structure and composition of the electrode,increasing the effective specific surface area of the electrode,or introducing functional groups on the electrode surface by chemical modification to increase the pseudocapacitance of the electrode material.Although these measures have some effect,they also lose the power density of the capacitor.In order to improve the energy density on the premise of ensuring the power density,this study introduces the mechanism of energy storage at the interface of electrode and electrolytic liquid phase.This paper mainly studies the influence of external potential and surface potential on the energy storage process of double-layer capacitors.Firstly,the effect of the potential difference between activated carbon and titanium dioxide electrodes on the performance of the capacitor was investigated.The voltage range and the open circuit voltage are taken as the research parameters and the relationship between them is represented by the variation of capacitor performance.In this process,when the voltage interval at both ends of the electrode material is symmetric with the open circuit voltage,the double layer has the same adsorption effect on the anions and the capacitor has the same energy density.If the voltage interval other than the open circuit voltage is selected,the specific capacitance of the capacitor can be improved.Secondly,by studying the Potential at the point of zero charge（PZC）and surface Zeta potential of Ti O₂ electrodes with different crystal structures,the influence rule of surface potential on capacitor performance was obtained.The results showed that the Zeta potential of rutile Ti O₂ thin film electrode was about-44.5 m V,and that of anatase electrode was-18.6 m V.And the PZC of the two is-0.11V and-0.14V respectively.The absolute value of Zeta potential and the larger PZC rutile thin film electrode had a larger specific electrode capacitance up to 41.82 m F/cm².In order to study the interface of the energy storage capacitor electrode in the solution process,this study through the experiment Ti O₂ crystal structures have been obtained respectively with the Zeta potential and the relationship between zero charge voltage,combined with the electrode materials involved in energy storage mechanism of ion exchange charged ion hydration model and density functional theory is analyzed in terms of energy storage,such as implemented in the electrical energy input remains unchanged under the premise of further increase the energy density of electric double layer capacitor.