▎ 摘　　要

Graphene has great potential in the application as supercapacitor electrode materials owing to its unique properties. However, it is challenging to find a facile and cost-efficient method using cheap raw materials for large-scale synthesis. Herein, a simple method is demonstrated for converting printing paper to graphene via one-step pyrolysis followed by washing. Various characterizations are used to analyze the obtained samples, revealing the typical graphene feature of the products. The sample obtained at 900 degrees C (denoted as G-900) shows a specific surface area of 514 m(2) g(-1) with a 50% mesopore volume. The symmetric supercapacitor using G-900 as an active electrode material gives rise to an ultrahigh power density of 49 kW kg(-1) at a high current density of 10 A g(-1), along with a great specific capacitance of 164.4 F g(-1). The capacitance retention ratio is as high as 93% after cycling for 4000 cycles at a current density of 1 A g(-1). As hundreds of million tons of paper are used annually, converting the waste paper to graphene is a scalable way for practical applications, associated with the facile conversion procedures.