Enhancing electrolyte ion diffusion via direct ink writing pillar array structure of graphene electrodes for high-performance microsupercapacitors

The graphene-based microsupercapacitors (MSCs) suffer from graphene aggregation issue in electrodes. It reduces the electrolyte ions transportation in the electrodes to degrade the charge storage ability of MSCs, hampering their practical application. Increasing the electrolyte ions transportation in the electrodes can boost the charge storage ability of MSCs. Herein, we design and experimentally realize pillar array structure of graphene electrodes for MSCs by direct ink writing technology. The graphene electrodes with pillar array structure increase the contact area with electrolyte and short the electrolyte ions transport path, facilitating electrolyte ions transport in electrodes. The MSCs exhibit high areal capacitance of 25.67 mF·cm⁻², high areal energy density of 20.54 µWh·cm⁻², and high power density of 1.45 mW·cm⁻². One single MSCs can power timer for 10 min and pressure sensor more than 160 min, showing high practical application possibility. This work provides a new avenue for developing high performance MSCs.