Molecular dynamics simulation of the effect of different factors on aqueous electrolyte supercapacitors

Abstract

Abstract The effects of temperature, graphene size and electrolyte concentration on the diffusion and structure of aqueous electrolyte of graphene supercapacitor were investigated via molecular dynamics simulation. By studying the average number of hydrogen bonds, the number density distribution, the mean square displacement and the diffusion coefficient, we found that the temperature and concentration have obvious effects on the properties of the system, while the graphene size has little effect on the properties of the system. With increasing concentration of ethylene glycol, the hydrogen bonding network between water molecules is gradually broken, and then the average number of hydrogen bonds between water molecules decreases, while the average number of hydrogen bonds between water and ethylene glycol molecules increases. Ethylene glycol is more capable of forming hydrogen bonds than water molecules. Therefore, the addition of ethylene glycol creates a good protection of the water molecules. This reduces the sensitivity of water molecules to temperature, improves their stability and inhibits their decomposition.