Unraveling the Effect of Electric Discharge Machining Current on the Fabrication of 3D Mo‐Doped VO0.2 Integrated Microsupercapacitors

Abstract

Vanadium oxides are widely used for microsupercapacitors (MSCs) due to their multiple‐valence and high theoretical capacitance. A conceptually new approach of electric discharge machining (EDM) with computer‐aided control is developed to one‐step fabricate Mo‐doped VO0.2‐based electrodes and devices with designable geometry. The results demonstrate that the Mo@VO0.2 integrated interdigital MSCs (IIMSCs) with the narrowest electrode distance of 300 μm show the best capacitive performance, which is furtherly manifested by the electric field simulation. Moreover, this work concentrates on expounding the relationships between the EDM machining current, surface morphology of Mo@VO0.2, and the capacitive behavior of Mo@VO0.2 IIMSCs. Compared to the machining current of 2 and 3 A, the machining current of 1 A facilitates synthesizing smaller Mo@VO0.2 particles with more porosity and higher surface area and thus achieving a larger capacitance value for Mo@VO0.2 IIMSCs device, which is achieving 32 mF cm−2 at 1 mV s−1, working well up to an ultrahigh scan rate of 30 V s−1, and obtaining a good cyclic stability of 88.61% after 5000 cycles. Moreover, this innovative EDM approach opens a new avenue for one‐step synthesis of various ceramic metal oxides for various microdevices such as microbatteries and microsensors.