Cost-effective fabrication of high-performance flexible all-solid-state carbon micro-supercapacitors by blue-violet laser direct writing and further surface treatment

Abstract

A facile and cost-effective method for the fabrication of all-solid-state flexible carbon micro-supercapacitors (MSC) was demonstrated by laser direct writing on polyimide (PI) sheets with a compact and low-cost 405 nm semiconductor blue-violet laser, the beam of which was almost totally absorbed in the PI sheet. The obtained MSCs exhibit high performances due to the hierarchical porous structures and large thickness. Furthermore, surface treatment by air-plasma etching was employed to improve the contact interface between the carbon structures and the electrolyte, which may also influence pore structures, thus largely enhancing the MSC performance. The typical MSCs after plasma treatment for 100 s show an improved specific capacitance as high as 18.3 mF cm⁻² at a scan rate of 10 mV s⁻¹ and 31.9 mF cm⁻² at a current density of 0.05 mA cm⁻², both of which are higher than most of the carbon material-based MSCs reported till now. Moreover, the MSCs show good flexibility, long-time cycle stability, as well as temperature tolerance up to 80 °C. In addition, the voltage and capacitance can be scaled up by simply connecting a single MSC in series, parallel or both. The facile fabrication, low cost, and good performance make carbon-based MSCs fabricated by semiconductor laser direct writing promising candidates for on-chip energy storage devices.