MgO-templated hierarchical porous carbon sheets derived from coal tar pitch for supercapacitors

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• 作者：Weidan Geng ; Fangwei Ma ; ^{Fangwei_ma@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Guang Wu ; Shijiao Song ; Jiafeng Wan ; ^{wanjiafeng@hlju.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Di Ma
• 关键词：Porous carbon sheets ; coal tar pitch ; MgO template ; KOH activation ; supercapacitor
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 February 2016
• 年：2016
• 卷：191
• 期：Complete
• 页码：854-863
• 全文大小：1376 K

文摘

Two-dimensional hierarchical porous carbon sheets (FHPCs) have been prepared by using nano-MgO sheet as template and coal tar pitch as carbon precursor coupled with KOH activation. The weight ratio of pitch with potassium hydroxide (KOH) exerts a marked effect on the porosity of the carbon. The FHPCs materials show some advantages for electrochemical energy storage including a specific surface area of 1454∼1604 m² g⁻¹, sheet structure, hierarchical porosity with macro/meso/micropores, rich O-doping (19 wt%). Resulting from the multiple synergistic effects of these advantages, the FHPC_1:2 electrode can achieve a high capacitance of 290 F g⁻¹ and 250 F g⁻¹ at 1 A g⁻¹, 20 A g⁻¹, respectively, and excellent rate capability with 86% retention rate in 6 M KOH electrolyte. The FHPC_1:2 symmetric supercapacitor displays a high energy density of 20.28 Wh kg⁻¹ at a power density of 873 W kg⁻¹ and retains as high as 8.87 Wh kg⁻¹ at 6389 W kg⁻¹ in 1 M Na₂SO₄ electrolyte. Our work demonstrates that KOH activation coupled with flake-like MgO template can act as an excellent route to prepare hierarchical porous carbon sheets from coal tar pitch for high performance supercapacitors.