Novel electrode geometry for high performance CF/Fe₂O₃ based planar solid state micro-electrochemical capacitors

A novel geometry of sharp-edged electrodes for planar micro-electrochemical capacitors is utilized for an enhanced performance compared to the conventionally used interdigitated electrodes. The sharp-edged electrode geometry achieves a 68% enhancement in the electric field at the sharp-edge of the electrodes as compared to interdigitated electrodes. Moreover, carbon foam with high specific surface area loaded with iron oxide nanoparticles allows a large mass loading for the pseudocapacitance in addition to electric double layer capacitance (EDLC). Thus, an enhancement of 235% was obtained in both the areal specific capacitance and energy density when the performance was compared with the interdigitated electrode based supercapacitors. Moreover, an excellent cycling stability (∼99.5%) over 10 000 charge-discharge cycles was also achieved. The high-performance architecture of sharp-edged electrodes paves a way for smart electrochemical capacitors using an efficient planar structure in combination with high-loading materials for large pseudocapacitance as well as EDLC.