Evaluating the Role of Nanostructured Current Collectors in Energy Storage Capability of Supercapacitor Electrodes with Thick Electroactive Materials Layers
Evaluating the Role of Nanostructured Current Collectors in Energy Storage Capability of Supercapacitor Electrodes with Thick Electroactive Materials Layers
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DOI：
10.1002/adfm.201705107
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发表时间：
2018-02-07
影响因子：
19
通讯作者：
Lei, Yong
中科院分区：
文献类型：
--
作者：
Liu, Long;Zhao, Huaping;Lei, Yong
电活性材料（特别是赝电容材料）一般以超薄共形涂层的形式存在于基于纳米结构集流器的超级电容器电极中；因此，电活性材料的低质量负载在很大程度上限制了纳米结构集流器的应用。本文制备了以镍纳米棒阵列为纳米结构集流器、二氧化锰为电活性材料的超级电容器电极，研究了当电活性材料处于厚层而非超薄保形涂层中时，纳米结构集流器对储能能力的影响。电化学分析表明，Ni纳米棒可以在厚层电极中形成许多导电隧道，从而显著减轻电活性材料/集流器界面处的接触电阻。在厚度为1 μ m的MnO2层下，Ni纳米棒电极的面电容比以Ni箔作为集流电极的面电容高得多，是相同MnO2质量负载下的6倍以上，是相同厚度MnO2层下的18倍以上。此外，即使在3 μ m厚的MnO2层上，Ni纳米棒电极也能保持较好的速率性能和较高的结构稳定性。这些结果为纳米结构集流器构建具有优异储能能力的超级电容器开辟了新的机会。
Electroactive materials (especially pseudocapacitive materials) are generally in the form of ultrathin conformal coating in supercapacitor electrodes based on nanostructured current collectors; thus, the resultant low mass loading of electroactive materials largely limits the applications of nanostructured current collectors. Here, supercapacitor electrodes with nickel nanorod arrays as nanostructured current collectors and MnO2 as electroactive materials are fabricated to study the role of nanostructured current collectors in determining the energy storage capability when electroactive materials are in thick layer rather than ultrathin conformal coating. Electrochemical analysis reveals that Ni nanorods could create numerous electrical conductive tunnels in the thick-layer electrodes to dramatically alleviate the contact resistance at the electroactive-material/current-collector interface. With 1 mu m thick MnO2 layer, the Ni nanorods based electrodes have much higher areal capacitance than those with Ni foils as current collectors, which is more than six times of that with the same MnO2 mass loading or more than 18 times of that with the same 1 mu m thick MnO2 layer. Moreover, better rate capability and higher structural stability is maintained in Ni nanorods based electrodes even with 3 mu m thick MnO2 layer. These results open up new opportunities for nanostructured current collectors to construct supercapacitors with superior energy storage capability.