How the Thermal Effect Regulates Cyclic Voltammetry of Supercapacitors

Cyclic voltammetry (CV) is a powerfultechnique for characterizingthe electrochemical properties of electrochemical devices. Duringcharging-discharging cycles, the thermal effect can have aprofound effect on its performance. However, existing theoreticalmodels cannot clarify such an intrinsic mechanism and often give poorpredictions. Herein, we propose an interfacial model for the electro-thermalcoupling based on fundamentals in nonequilibrium statistical mechanics.By incorporation of molecular interactions, our model shows a quantitativeagreement with experimental measurements. The integral capacitanceshows a first enhanced and then decayed trend against the appliedheat bath temperature. Such a relation is attributed to the competitionbetween electrical attraction and Born repulsion via dielectric inhomogeneity,which was not well understood in previous models. In addition, asevidenced in recent experimental CV tests, our model predicts thenonmonotonic dependence of the capacitance on the bulk electrolytedensity. This work demonstrates a potential pathway toward next-generationthermal regulation of electrochemical devices.

Automated summary

Cyclic voltammetry (CV) is a powerful technique for characterizing electrochemical properties. Existing theoretical models cannot explain the intrinsic mechanisms accurately. In this study, a new interfacial model based on statistical mechanics is proposed, showing quantitative agreement with experimental results. This work has the potential to advance thermal regulation in next-generation electrochemical devices.