Topological Optimization of Flexible Supercapacitor Electrodes through Modelling and Direct Ink 3D‐Writing

Flexible, high surface area porous supercapacitors have caught great attention as energy storage devices. However, fabricating them through conventional methods have been challenging. The emergence of 3D printing has made it more effective to produce supercapacitors with both high capacitance and structural rigidity, while minimising material wastage. In this work, extrusion-based 3D printing, i.e. direct ink writing (DIW) has been used for the fabrication of flexible macroscale (centimetre scale) carbon-based interdigital (ID) electrodes of different geometries for supercapacitors. To investigate the effect of geometry and design on supercapacitor performance, electrochemical cyclic voltammetry (CV) analysis was performed through simulation and experiments on ID electrodes with different geometric parameters. The finite elemental analysis simulations carried out using COMSOL Multiphysics shows the interdependency of topology, surface area and capacitance. The maximum areal capacitance of ~33.2 Fcm -2 at 50 mVs -1 has been measured experimentally for the printed capacitors. The statistical validation of the experimental results is evaluated through regression analysis. Our findings described an approach to optimize the ID electrode design geometry for high capacitance with good structural rigidity using DIW. • Direct ink writing 3D printing of activated carbon (AC) slurry and preparation of gel electrolyte. • Fabrication of flexible and scalable interdigital electrodes of different geometry. • Optimisation of geometry through modelling and electrochemical experimental investigations. • Correlation of topological parameters and bending moment for optimum capacitance.