Activation-Free Synthesis of Chitin-Derived Porous Carbon: Application for Electrical Energy Storage

Abstract

High Resolution Image Download MS PowerPoint Slide Chitin-derived porous carbons (CDPCs) are synthesized by simply carbonizing chitin at 850 °C for 1 h under a N 2 atmosphere. This method is very simple and does not require any activation or washing processes. We study the effects of the heating rate (2–20 °C min –1 ) on their structural characteristics and electric double-layer capacitor performance. Pore development proceeds above 300 °C during heating chitin, and nitrogen in chitin remains in the CDPCs with nitrogen/carbon molar ratios of 0.053–0.055. Although their specific surface areas are only 300–327 m 2 g –1, three-electrode cell measurements in 1 M H 2 SO 4 reveal that their gravimetric and area-normalized capacitances at 0.05 A g –1 are as high as 173–177 F g –1 and 54–57 μF cm –2, respectively. The area-normalized capacitances exceed those reported for activated carbons derived from chitin. Moreover, they show high capacitance retentions of 49–52% at 10 A g –1 . Their high area-normalized capacitances and capacitance retentions are attributed to the coexistence of ultramicropores and mesopores along with high electrical conductivity due to a large amount of quaternary nitrogen and the absence of activation. Symmetrical two-electrode cell measurements show the practical energy and power densities of 4.9 W h kg –1 at 11.3 W kg –1 and 1.1 W h kg –1 at 1.5 kW kg –1 with a long cycle lifetime of 10,000 cycles. Our study demonstrates the significant contribution of utilizing biomass for electrode materials, aligning with the objectives of both United Nation’s Sustainable Development Goals 7 and 12. By enhancing clean energy accessibility (SDG 7) and promoting responsible consumption and production practices (SDG 12) through efficient resource utilization, we have paved the way for a more sustainable energy future.