Battery-type graphene/BiOBr composite for high-performance asymmetrical supercapacitor

Battery-type electrode materials are utilised in high performance supercapacitors. Herein, graphene/BiOBr (GR/BiOBr) composite is prepared by one-step solvothermal method and firstly used in supercapacitors. The results of the dynamic calculations suggest that the key feature of the GR/BiOBr composite is its battery-like performance. When used as an electrode in a three-electrode system, the GR/BiOBr composite can deliver an excellent specific capacity of 491 C g−1 at 1 A g−1. An asymmetrical supercapacitor cell with a voltage of 1.4 V for the aid of GR/BiOBr (negative electrode) and Ni–Co–Al LDH (positive electrode) is assembled. The symmetrical supercapacitor achieves a high energy density of 29.2 Wh kg−1 corresponding to a power density of 700 W kg−1. This study shows that GR/BiOBr composite has a great potential for high performance supercapacitors. [Display omitted] •GR/BiOBr composite is a battery-type electrode material.•GR/BiOBr gives an impressive specific capacity of 491 C g−1 in −1.2–0.2 V vs. SCE.•An asymmetrical supercapacitor based on GR/BiOBr has been characterized.