Carbon-based flexible micro-supercapacitor fabrication via mask-free ambient micro-plasma-jet etching

We demonstrate a general and facile method to fabricate all-solid-state flexible micro-supercapacitors (MSCs) with micropatterned multi-walled carbon nanotube (MWNT) electrodes via mask-free micro-plasma-jet etching in ambient conditions. Localized pulsed plasma jet etches the MWNTs rapidly and produces the interdigitated electrode patterns by scanning. This mask-free patterning technique is easy operated, cost-effective, readily scalable, free from photoresist contamination and applicable to various kinds of carbon-based materials. A solid-state polyvinyl alcohol-H3PO4 gel electrolyte is introduced to realize an all-solid-state flexible MSC assembly. Cyclic voltammetry measurements exhibit the expected electrical double layer behavior. The fabricated MSC with twelve interdigitated electrodes exhibits a stack capacitance of 2.02 F cm−3 at a scan rate of 10 mV s−1. Moreover, the MSC shows stable performance under repeated bending, with retention of 98.2% of capacitance after 600 bending cycles. Furthermore, both the output voltage and the total capacitance of the MSC could be controlled via the serial or parallel connection.

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