Ion–Image Interactions and Phase Transition at Electrolyte–Metal Interfaces

摘要: The arrangement of ions near a metallic electrode is crucial to energy storage in electrical double-layer capacitors. Classic Poisson-Boltzmann theory predicts that the charge stored double layer continuous function applied voltage. However, recent experiments and simulations strongly suggest presence voltage-induced first-order phase transition layer, leading hysteretic response: capacitance-voltage relation dependent on whether voltage increasing or decreasing. By developing simple analytical model, we show ion-image interaction could explain this transition. Moreover, our model shows depends bulk ionic liquid. Our results justify mixing liquids with solvents as way achieve large capacitance avoid hysteresis.