Printable High-Voltage Integrated Microsupercapacitors Based on Heteroatom-Doped Porous Biomass Carbon

The popularity of portable and wearable electronic equipment increases the demand for rapid, low-cost, and scalable production of microsupercapacitors (MSCs). However, the synthesis of two-dimensional materials and the fabrication of the reported MSCs are considerably time-consuming and intricate processes. Herein, we developed the low-cost and scalable fabrication of biomass-based planar MSCs with desirable flexibility, shape diversity, and tailorable voltage and capacitance output. The prepared N,S-doped carbon (KNSC) possesses a tunable specific surface area of 1323–2116 m2·g–1, hierarchical porous structure, and superior conductivity and delivers a high specific capacitance of 481 F·g–1. On the basis of the KNSC ink and screen-printing technique, we can also facilely extend this to construction of hundreds and thousands of MSCs connected in a serial and parallel fashion on a target substrate. As a proof of concept, the resulting stripes integrated MSCs with a complex connection fashion of 11 cells in series and 3 cells in a parallel pattern presented a record voltage output of 8.8 V and exceptional areal capacitance of 102.7 mF·cm–2, which can efficiently light up a white light-emitting diode.