Volume 8, Issue 3 1901103
Full Paper

Sustainable Porous Carbon with High Specific Surface Area from Soybean Shell via Hydrothermal Carbonization with H3PO4 for Electric Double-Layer Capacitor Applications

Yan Wu

Yan Wu

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Jing-Pei Cao

Corresponding Author

Jing-Pei Cao

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Xiao-Yan Zhao

Xiao-Yan Zhao

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Qi-Qi Zhuang

Qi-Qi Zhuang

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Zhi Zhou

Zhi Zhou

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Ming Zhao

Ming Zhao

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Xin Cui

Xin Cui

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Yun-Peng Zhao

Yun-Peng Zhao

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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Xian-Yong Wei

Xian-Yong Wei

Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining & Technology, Xuzhou, Jiangsu, 221116 China

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First published: 30 October 2019
Citations: 14

Abstract

Soybean shell (SS), as the byproduct of soybeans, is converted into porous carbon (PC) with a high specific surface area (SSA) via hydrothermal carbonization with H3PO4 followed by KOH activation. No obvious effect on the crystal structure of PC can be found by addition of H3PO4 during the hydrothermal process. However, the SSA of PC increases remarkably compared with hydrothermal carbonization without H3PO4, as H3PO4 assists in hydrothermal carbonization dehydration reactions and creates some pores beneficial for KOH activation. The SSA of the obtained PC reaches 2523 m2 g−1, and the hierarchical pore structure is mainly in 0.6–50 nm. The sample prepared by hydrothermal carbonization with 10 wt% H3PO4 and activation by KOH with the ratio of KOH/10-hydrochar 3 under 700 °C exhibits a specific capacitance of 301 F g−1 in 6 m KOH electrolyte at the current density of 0.1 A g−1. It also has an excellent cycling stability with the specific capacitance remaining at 93.8% after 15 000 cycles. Furthermore, the energy density is 8.1 Wh kg−1 in the two-electrode system. These results display that PC based on SS is a promising electrode material for the electric double-layer capacitor.

Conflict of Interest

The authors declare no conflict of interest.

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