Preparation of nanowires on free-standing boron-doped diamond films for high performance micro-capacitors
Résumé
A free-standing nanostructured boron-doped diamond (BDD) electrode was fabricated by reactive ion etching (RIE) with oxygen plasma. The free-standing architecture and nanowires endowed the BDD electrode with high specific capacitance and good stability. As a result, the BDD nanowires electrode etched for 60 min (BDD-NWs-60) featured the best capacitive performance with a specific capacitance of 24.9 mF cm−2 at a scan rate of 10 mV s−1 and capacitance retention of 90% after 6,000 cycles at a constant current density of 1.0 mA cm−2. Furthermore, a symmetric capacitor device was assembled using two BDD-NWs-60 electrodes, the device exhibited the highest energy and power densities of 0.41 mJ cm−2 and 0.79 mW cm−2, respectively. For a practical application, three BDD-NWs-60//BDD-NWs-60 symmetrical capacitors in series could light a red LED and rotate a homemade fan. Based on the above satisfactory behavior of the BDD electrode, the influence of the RIE process on the capacitive performance of the BDD electrode was proposed.