One-step laser direct writing of boron-doped electrolyte as all-solid-state microsupercapacitors

Abstract

High specific energy microsupercapacitor (MSC) as miniature all solid-state energy storage device has attracted wide interest due to its high energy and power density, long cycle life, integrability and high safety. Here, we designed and fabricated symmetric microsupercapacitors by one-step laser direct writing of boron-doped electrolytes (B-LE). The boron-doped PVA/H2SO4 electrolyte was carbonized into interdigitated cross-linked porous carbon fiber electrodes by high energy laser irradiation. These devices can deliver a high areal capacitance of 1.57 mF cm−2 (corresponding volumetric capacitance of 3.14 F cm−3) at the current density of 0.01 mA cm−2 with 5 wt% H3BO3 loading, much higher than the devices without boron doping (0.40 mF cm−2 at the same current density). Moreover, the fabricated devices display good cycling stability with a capacitance retention of 89.27% after 3000 charge-discharge cycles. These results suggest that the one-step direct laser writing to fabricate symmetric MSC has broad applications in high energy and power storage devices for miniaturized electronics.