Modeling galvanostatic charge-discharge of nanoporous supercapacitors

Molecular modeling has been considered indispensable in studying the energy storage of supercapacitors at the atomistic level. The constant potential method (CPM) allows the electric potential to be kept uniform in the electrode, which is essential for a realistic description of the charge repartition and dynamics process in supercapacitors. However, previous CPM studies have been limited to the potentiostatic mode. Although widely adopted in experiments, the galvanostatic mode has rarely been investigated in CPM simulations because of a lack of effective methods. Here we develop a modeling approach to simulating the galvanostatic charge-discharge process of supercapacitors under constant potential. We show that, for nanoporous electrodes, this modeling approach can capture experimentally consistent dynamics in supercapacitors. It can also delineate, at the molecular scale, the hysteresis in ion adsorption-desorption dynamics during charging and discharging. This approach thus enables the further accurate modeling of the physics and electrochemistry in supercapacitor dynamics.

Automated summary

Molecular modeling is essential in studying energy storage of supercapacitors at the atomistic level, with the constant potential method providing a realistic description of charge repartition and dynamics. A new modeling approach has been developed to simulate the galvanostatic charge-discharge process of supercapacitors under constant potential, showing experimentally consistent dynamics and hysteresis in ion adsorption-desorption at the molecular scale. This approach enables accurate modeling of physics and electrochemistry in supercapacitor dynamics.