Analysis of energy storage performance of supercapacitors with crumpled graphene electrodes

Abstract

The Electric Double Layer Capacitors (EDLC)are one of the most promising technologies now-a-days in the field of energy storage due to its excellent power density, great cyclability and faster charging-discharging. However, having a lower energy density than batteries leading researchers to optimize the performance of supercapacitors by enhancing their energy storage capability. Improving the electrode design of the supercapacitors has been the primary approach in this regard. In this study, to enhance the capacitive performance of supercapacitors, EDLC with crumpled graphene electrode has been designed with aqueous (NaCl) electrolyte. This study is performed with the aid of molecular dynamics (MD) simulation to analyze the influence of crumpled graphene electrode on the EDLC performance. The findings show that the proposed EDLC model possesses five times higher specific capacitance (16.351 F/cm-2) than the planar graphene. Better charging mechanism and higher ion accessible area are the reasons behind this improved performance. In addition, the effects of the degree of crumpling of graphene, inclusion of defects on the crumpled graphene surface, and the variation of surface wettability on the performance of the modeled EDLC are also examined. The effect of degree of crumpling is found to be that complete crumpling aids the capacitive ability of the EDLC. The most optimized structure of the crumpled graphene electrode is observed for an added vacancy of 20% which possesses an outstanding specific capacitance of 19.8F/cm-2. Finally, for the effect of surface wettability, it is observed that super-hydrophilic electrodes facilitate better electrode-electrolyte interaction and improves ion separation, leading to a superior performance than the hydrophobic surfaces. The major takeaway from the project is that it provides significant insight into the potential of crumpled graphene electrode-based EDLC and sheds light on the possibility of achieving the desired balance of high-storage and high-power energy.