79 / 2019-10-30 19:28:59

A NOVEL STRATEGY TO PREPARE N, S-CODOPED POROUS CARBONS DERIVERD FROM BARLEY WITH HIGH SURFACE AREA FOR SUPERCAPACITORS

Barley; Chemical activation; Copper citrate; Porous carbon; Supercapacitor

In this work, barley derived N, S-codoped porous carbons (BPC) were synthesized through a simple, one-step chemical activation method using copper citrate as an activating agent. The copyrolysis of barley and copper citrate contributes to the formation of numerous micro-/mesopores and the high surface area after activation and acid washing process. Owing to redox reactions between copper citrate and carbon matrix during the activation process, the as-prepared carbon possesses a ultrahigh specific surface area of 2139.6 m2 g-1, hierarchical porous architecture with a large pore volume of 1.16 cm3 g-1, and high nitrogen, oxygen and sulfur contents. The resultant carbon exhibits a high specific capacitance of 401.6 F g-1 at 0.5 A g-1 and good rate capability with the capacitance remaining 165.6 F g-1 at 100 A g-1. Additionally, the assembled symmetric carbon-based supercapacitor delivers a high energy density of 30.9 Wh kg-1 and superior long-term cycling stability of 94.8% capacitance retention after 20,000 cycles in 1.0 M Na2SO4 electrolyte. This work provides a facile strategy to design high-surface-area porous carbons with adjustable pore structure and rich heteroatom amount, which holds a promising future for constructing high energy carbon-based supercapacitors.