▎ 摘　　要

Herein, we studied the nitrogen-doped reduced graphene oxide (N-doped RGO) as an excellent electrode materials in energy storage applications. The N-doped RGO based solid-state symmetric supercapacitor (SSC) device shows high specific capacity (141.1 mA h g(-1)) and high energy density (28.2 W h kg(-1)). The N-doped RGO based SSC device illustrates the notable stabilities of similar to 95.4% via 10,000 galvanostatic charging-discharging (GCD) cycles and similar to 93.2% via 8 h voltage holding tests. Additionally, the N-doped RGO based SSC device shows outstanding self-discharge properties, which retains the voltages of 0.65 V, 0.69 V, 0.68 V and 0.70 V of its initial voltage (1.2 V) after each GCD cycling + 2 h voltage holding test + 2 h self-discharge test, respectively, which vindicates the excellent state of health of the supercapacitor device. (C) 2019 Elsevier B.V. All rights reserved.