Recycle of industrial waste: a new method of applying the paint residue to supercapacitors

Herein, paint residue (PR), a kind of industrial waste, is firstly used as a raw material for the synthesis of the activated carbon (AC) for supercapacitors via a simple and traditional two-step strategy before rinsing. The hydrofluoric acid greatly affects the structure of the AC, thereby affecting the performance of the supercapacitor. As evaluated in a three-electrode 6.0 M KOH system, the material exhibits a high gravimetric capacitance of 254 F g−1 at a current density of 1.0 A g−1, and excellent cycling stability with 100% retention after 10000 cycles. A voltage window of 0–1.4 V due to its high oxygen and heteroatom contents in a symmetrical supercapacitor from PR, which demonstrates a comparatively higher energy density of 15.22 Wh kg−1 at a power density of 1081 W kg−1, with good rate capability of 70% retention at 10 A g−1. The favorable capacitive performances make this environmentally unfriendly residue PR act as a new resource of carbonaceous materials for high-performance supercapacitors.