Hybrid nanomaterial of α-Co(OH)₂ nanosheets and few-layer graphene as an enhanced electrode material for supercapacitors

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• 作者：J.P. Cheng^a ; ^{chengjp@zju.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; L. Liu^a ; K.Y. Ma^a ; X. Wang^b ; Q.Q. Li^b ; J.S. Wu^b ; F. Liu^a
• 关键词：Cobalt hydroxide ; Few-layer graphene ; Delamination ; Electrochemical capacitor
• 刊名：Journal of Colloid and Interface Science
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：486
• 期：Complete
• 页码：344-350
• 全文大小：2495 K

文摘

Supercapacitor with metal hydroxide nanosheets as electrode can have high capacitance. However, the cycling stability and high rate capacity is low due to the low electrical conductivity. Here, the exfoliated α-Co(OH)₂ nanosheets with high capacitance has been assembled on few-layer graphene with high electric conductivity by a facile yet effective and scalable solution method. Exfoliated hydrotalcite-like α-Co(OH)₂ nanosheets and few-layer graphene suspensions were prepared by a simple ultrasonication in formamide and N-methyl-2-pyrrolidone, respectively. Subsequently, a hybrid was made by self-assembly of α-Co(OH)₂ and few-layer graphene when the two dispersions were mixed at room temperature. The hybrid material provided a high specific capacitance of 567.1 F/g at 1 A/g, while a better rate capability and better stability were achieved compared to that mad of pristine and single exfoliated α-Co(OH)₂. When the hybrid nanocomposite was used as a positive electrode and activated carbon was applied as negative electrode to assembly an asymmetric capacitor, an energy density of 21.2 Wh/kg at a power density of 0.41 kW/kg within a potential of 1.65 V was delivered. The high electrochemical performance and facile solution-based synthesis method suggested that the hybrid of exfoliated α-Co(OH)₂/few-layer graphene could be a potential electrode material for electrochemical capacitor.