One-step strategy to graphene/Ni(OH)2 composite hydrogels as advanced three-dimensional supercapacitor electrode materials
One-step strategy to graphene/Ni(OH)2 composite hydrogels as advanced three-dimensional supercapacitor electrode materials
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DOI：
10.1007/s12274-012-0284-4
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发表时间：
2012
期刊：
影响因子：
9.9
通讯作者：
Yuxi Xu;Xiaoqing Huang;Zhaoyang Lin;Xing Zhong;Yu Huang;X. Duan
中科院分区：
文献类型：
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作者：
Yuxi Xu;Xiaoqing Huang;Zhaoyang Lin;Xing Zhong;Yu Huang;X. Duan
石墨烯基三维（3D）宏观材料由于其在电化学能量转换和储存方面的潜在应用而引起了人们越来越多的兴趣。在这里，我们报告了一个简单的一步战略，以制备机械强度和导电石墨烯/Ni（OH）2复合水凝胶与互连的多孔网络。复合水凝胶直接用作3D超级电容器电极材料，而不添加任何其他粘合剂或导电添加剂。优化的复合水凝胶含有约82 wt.% Ni（OH）2在5 mV/s和40 mV/s扫描速率下的比电容分别为1, 247 F/g和785 F/g（电容保持率约为63%），具有良好的循环稳定性。3D水凝胶的容量大大超过石墨烯片和Ni（OH）2纳米片的物理混合物的容量（在40 mV/s下为309 F/g）。同样的策略也被应用于制备石墨烯-碳纳米管/Ni（OH）2三元复合水凝胶，其具有进一步改善的比电容（在5 mV/s下为1,352 F/g）和倍率性能（在40 mV/s下为66%的电容保持率）。这里获得的两种复合水凝胶都可以提供高能量密度（分别为1043和1047 Wh/kg）和功率密度（分别为1080和1090 kW/kg），使它们成为超级电容器应用的有吸引力的电极材料。这项研究为功能性3D石墨烯复合材料的设计和制造开辟了一条新的途径，并可能对包括储能等在内的广泛领域产生重大影响。
Graphene-based three-dimensional (3D) macroscopic materials have recently attracted increasing interest by virtue of their exciting potential in electrochemical energy conversion and storage. Here we report a facile one-step strategy to prepare mechanically strong and electrically conductive graphene/Ni(OH)2composite hydrogels with an interconnected porous network. The composite hydrogels were directly used as 3D supercapacitor electrode materials without adding any other binder or conductive additives. An optimized composite hydrogel containing ∼82 wt.% Ni(OH)2exhibited a specific capacitance of ∼1,247 F/g at a scan rate of 5 mV/s and ∼785 F/g at 40 mV/s (∼63% capacitance retention) with excellent cycling stability. The capacity of the 3D hydrogels greatly surpasses that of a physical mixture of graphene sheets and Ni(OH)2nanoplates (∼309 F/g at 40 mV/s). The same strategy was also applied to fabricate graphene-carbon nanotube/Ni(OH)2ternary composite hydrogels with further improved specific capacitances (∼1,352 F/g at 5 mV/s) and rate capability (∼66% capacitance retention at 40 mV/s). Both composite hydrogels obtained here can deliver high energy densities (∼43 and ∼47 Wh/kg, respectively) and power densities (∼8 and ∼9 kW/kg, respectively), making them attractive electrode materials for supercapacitor applications. This study opens a new pathway to the design and fabrication of functional 3D graphene composite materials, and can significantly impact broad areas including energy storage and beyond.