Porous NiCo2O4-reduced graphene oxide (rGO) composite with superior capacitance retention for supercapacitors
Porous NiCo2O4-reduced graphene oxide (rGO) composite with superior capacitance retention for supercapacitors
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DOI：
10.1016/j.electacta.2014.03.179
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发表时间：
2014-06
影响因子：
6.6
通讯作者：
Yazi Luo;Haiming Zhang;Di Guo;Jianmin Ma;Q. Li;Libao Chen;Taihong Wang
中科院分区：
文献类型：
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作者：
Yazi Luo;Haiming Zhang;Di Guo;Jianmin Ma;Q. Li;Libao Chen;Taihong Wang
在目前的工作中，我们开发了一种简单而绿色的路线来制造负载在泡沫镍基底上的不规则多孔网络状NiCo2O4还原氧化石墨烯（rGO）纳米复合材料，该复合材料可直接用作超级电容器的无粘合剂电极。 rGO作为导电网络，有利于循环过程中电子的收集和传输，提高了NiCo2O4的电导率，并允许更大的比表面积。不规则的多孔结构使电解质能够轻松扩散到电极的内部区域。此外，直接在泡沫镍上制备的纳米复合材料具有更好的附着力，并且避免了聚合物粘合剂的使用。该方法有效地降低了欧姆极化并提高了倍率性能。结果，NiCo2O4-rGO纳米复合材料在5 A g−1时表现出777.1 F g−1的比电容，并且在3000次循环后保留了约99.3%的电容。当电流密度从1 A g−1增加到20 A g−1时，电容保持率约为87.6%。这些结果表明，直接在基底上合成的这种不规则多孔网络状结构可能是高性能储能应用的有希望的候选者。
In present work, we developed a simple and green route to fabricate irregular porous network-like NiCo2O4-reduced graphene oxide (rGO) nanocomposite supported on the nickel foam substrates, which was directly used as a binder-free electrode for supercapacitors. The rGO served as a conductive network to facilitate the collection and transportation of electrons during the cycling, improved the conductivity of NiCo2O4, and allowed for a larger specific surface area. The irregular porous structure allowed for the easy diffusion of the electrolyte into the inner region of the electrode. Moreover, the nanocomposite directly fabricated on nickel foam with a better adhesion and avoided the use of polymer binder. This method efficiently reduced ohmic polarization and enhanced the rate capability. As a result, the NiCo2O4-rGO nanocomposite exhibited a specific capacitance of 777.1 F g−1at 5 A g−1and about 99.3% of the capacitance retained after 3000 cycles. The capacitance retention was about 87.6% when the current density increased from 1 A g−1to 20 A g−1. These results indicated that such the irregular porous network-like structure directly synthesized on the substrate could be a promising candidate for high performance energy storage application.