In Situ N, O Co-Doped Nanoporous Carbon Derived from Mixed Egg and Rice Waste as Green Supercapacitor

Abstract

The conversion of nitrogen–oxygen-rich biomass wastes into heteroatomic co-doped nanostructured carbons used as energy storage materials has received widespread attention. In this study, an in situ nitrogen–oxygen co-doped porous carbon was prepared for supercapacitor applications via a two-step method of pre-carbonization and pyrolytic activation using mixed egg yolk/white and rice waste. The optimal sample (YPAC-1) was found to have a 3D honeycomb structure composed of abundant micropores and mesopores with a high specific surface area of 1572.1 m2 g−1, which provided abundant storage space and a wide transport path for electrolyte ions. Notably, the specific capacitance of the constructed three-electrode system was as high as 446.22 F g−1 at a current density of 1 A g−1 and remained above 50% at 10 A g−1. The capacitance retention was 82.26% after up to 10,000 cycles. The symmetrical capacitor based on YPAC-1 with a two-electrode structure exhibited an energy density of 8.3 Wh kg−1 when the power density was 136 W kg−1. These results indicate that porous carbon materials prepared from mixed protein and carbohydrate waste have promising applications in the field of supercapacitors.

Mild and Efficient One-Step Synthesis of Nitrogen-Doped Multistage Porous Carbon for High-Performance Supercapacitors

“…Commercial activated carbons are still the most common electrode materials today; unfortunately, they are mainly obtained from fossil fuels, and the precursors are environmentally unfriendly and expensive. Hence, using natural and abundant biowastes from domestic, industrial, animal, and municipal wastes to obtain carbon materials has attracted great attention [16][17][18]. Tobacco straw is the most dominant by-product of the tobacco industry, and the amount produced is about 4.5 × 10 6 t per year in China [19]; most of it is discarded or incinerated, leading to environmental pollution and resource wastage.…”