Tailoring the defects of two-dimensional borocarbonitride nanomesh for high energy density micro-supercapacitor

Abstract

The development of high-performance micro-supercapacitors (MSCs) highlights two-dimensional (2D) carbon materials with pseudocapacitive charge storage capacity. However, improving the electrochemical performances of these electrode materials is still challenging. Here, we synthesized 2D borocarbonitride nanomesh (BCNN) by carbonizng gel precursor of milk powder and boron oxide in 700, 800, and 900 °C, respectively, denoted as BCNN700, BCNN800, and BCNN900, as electrode for MSCs. By tailoring defects and atomic contents of BCNN, the areal capacitance increases from 30.5 mF cm−2 for BCNN700-MSCs to 80.1 mF cm−2 for BCNN900-MSCs with a hydrogel electrolyte. Notably, BCNN900-MSCs can provide a high energy density of 67.6 mWh cm−3with an ion-gel electrolyte, efficiently powering a liquid crystal display for 328 s. In addition, a first principles simulation verifies the effects of the dopants and pores on improving the total capacitance of BCNN by enhancing qauntam capacitance. Therefore, BCNN exhibits tremendous potential for applying on future energy storage devices.