High Performance Capacitors Based on Graphene and Boron Nitride

Abstract

Flexible all-solid-state supercapacitors (FASS) are energy supplies for wearable electronic devices and power devices. Graphene nanosheets have unique two-dimensional (2D) structures, strong mechanical properties, and an excellent electrical conductivity, which are widely used in paper-like flexible electrodes. The essential feature of the double-layer electric performance for the simple graphene nanosheet-based FASS restricts the improvement of their capacitive performance and practical applications. FASS based on the ultralarge graphene nanosheets and the ultrathin boron nitride (BN) nanosheets are investigated. The nacre-like structures could efficiently integrate both merits of pseudocapacitive BN nanoflakes and conducting graphene, thereby exhibiting an excellent electrochemical performance in FASS. After 5000 charge-discharge cycles, the highest areal specific capacitance of FASS reaches 325.4 mF/cm2, with a high capacity retention rate of about 86.2% and a high energy density of 22.8 W·h/kg (1 W·h=3.6 kJ) at a power density of 85.7 W/kg.

Keywords

• flexible all-solid-state supercapacitors (fass)
• graphene
• boron nitride (bn)