Influence of electrode pore size and electrolyte on carbon aerogel supercapacitors: insights from experimental studies and molecular simulations

Abstract

This study investigates the enhancement of supercapacitor energy density by exploring the role of carbon aerogel (CA) electrode pore size and aqueous electrolyte compositions by employing a combination of experimental techniques and molecular dynamics simulations. Supercapacitors, known for their rapid charge–discharge cycles and longer lifespans, face the challenge of lower energy density compared to lithium-ion batteries. To address this, recent state-of-the-art advancements have focused on optimizing electrode architecture, such as hierarchical porous carbon structures, and fine-tuning electrolyte compositions to maximize ion-transport efficiency and capacitance. Our research integrates these modern strategies by leveraging high-fidelity 3D modeling of carbon electrode pores at different quench rates to guide the synthesis of CA electrodes with precise pore size distributions. We assessed the performance of these optimized electrodes in supercapacitor systems using cutting-edge electrolytes, including 3 M aqueous KOH and 1 M Na2SO4, both recognized in current research for their high ionic conductivity and compatibility with porous carbon materials. Notably, the KOH-based system demonstrated superior specific capacitance, attributed to the increased surface area and enhanced ion accessibility of K+ and OH– ions within the optimized CA structure. The specific capacitance values measured experimentally for the KOH system at 1 A/g (119 F/g) showed a strong correlation with molecular dynamics simulation predictions (128 F/g), underscoring the accuracy and predictive power of modern computational techniques in electrode design.