Micro-supercapacitors based on three dimensional interdigital polypyrrole/C-MEMS electrodes

Symmetric micro-supercapacitors with three dimensional (3D) interdigital electrode structures have been designed and fabricated through Carbon-microelectrochemical system (C-MEMS) technology. The micro-supercapacitor consists of a 3D C-MEMS structure which serves as a high effective surface area current collector and conformal polypyrrole (PPy) films deposited on the carbon structures as electroactive materials. The electrochemical performance of single electrodes and symmetric micro-supercapacitor cells were evaluated by cyclic voltammetry (CV) at different scan rates and galvanostatic charge/discharge tests. The effect of the 3D electrode structure on the performance of the micro-supercapacitor was studied. Single PPy/C-MEMS electrodes presented a specific capacitance of 162.07 +/- 12.40 mF cm(-2) and a specific power of 1.62 +/- 0.12 mW cm(-2) at 20 mV s(-1) scan rate. The symmetric micro-supercapacitor cells exhibited an average specific capacitance of 78.35 +/- 5.67 mF cm(-2) and a specific power of 0.63 +/- 0.04 mW cm(-2) at 20 mV s-1 scan rate, demonstrating that 3D micro-supercapacitors are promising for applications that require high power in a limited footprint area of the device. (C) 2011 Elsevier Ltd. All rights reserved.