Abstract
Biomass-based porous carbon materials have appeal due to their low cost, abundance and sustainability. In this report, a novel kind of heteroatom (N, S) co-doped 2D porous activated carbon using turnip as biomass has been prepared with subsequent non-toxic dual activators. At optimized activation temperature, the activated carbon from turnip-derived using KCl/NaCl (ACTKNa) as activators shows excellent surface area of 1938 m2·g−1 with micro-mesopores distributions. Importantly, ACTKNa as electrode materials for supercapacitors exhibits a superb capacitance value of 570 F·g−1 (0.5 A·g−1) and retains high stability. Interestingly, a symmetric ACTKNa//ACTKNa device can work in the potential window (0–1.5 V) under neutral Na2SO4 solution. Among them, the symmetric device delivers specific energy value 47.5 Wh·kg−1 at specific power of 372 W·kg−1 with outstanding rate capability of 86 % after 20,000 cycles. This work opens the way to enhance the specific energy value by increasing the potential window using neutral electrolyte.
We highlight an environmentally friendly strategy to successfully prepare N, S co-doped turnip-derived porous activated carbons using neutral, non-toxic and non-corrosive dual activators NaCl/KCl. The obtained carbon material had large surface area (1938 m2·g−1), and exhibited a superior specific capacitance (570 F·g−1 at 0.5 A·g−1) and retains high stability as electrode material of supercapacitor. The symmetric ACTKNa//ACTKNa device with the potential window (0–1.5 V) could deliver excellent specific energy value 47.5 Wh·kg−1 at specific power of 372 W·kg−1. [Display omitted]
•N/S co-doped 2D porous activated carbon were prepared from turnip biomass.•Non-toxic and non-corrosive neutral double salts NaCl/KCl were used as activator.•The porous carbon exhibited high specific capacitance of 570 F·g−1 at 0.5 A·g−1.•The device delivers specific energy of 47.5 Wh·kg−1 at specific power of 372 W·kg−1.