具有改进电化学性能的用于不对称超级电容器的碱蚀刻镍钴铝层状双氢氧化物
Alkali-Etched NiCoAl-LDH with Improved Electrochemical Performance for Asymmetric Supercapacitors.
作者信息
Hou Liyin, Zhou Xufeng, Kong Lina, Ma Zhipeng, Su Li, Liu Zhaoping, Shao Guangjie
机构信息
College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China.
Key Laboratory of Graphene Technologies and Applications of Zhejiang Province and Advanced Li-Ion Battery Engineering Laboratory, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of SciencesState, Zhejiang 315201, China.
出版信息
Nanomaterials (Basel). 2023 Mar 27;13(7):1192. doi: 10.3390/nano13071192.
Hydrotalcite, first found in natural ores, has important applications in supercapacitors. NiCoAl-LDH, as a hydrotalcite-like compound with good crystallinity, is commonly synthesized by a hydrothermal method. Al3+ plays an important role in the crystallization of hydrotalcite and can provide stable trivalent cations, which is conducive to the formation of hydrotalcite. However, aluminum and its hydroxides are unstable in a strong alkaline electrolyte; therefore, a secondary alkali treatment is proposed in this work to produce cation vacancies. The hydrophilicity of the NiCoAl-OH surface with cation vacancy has been greatly improved, which is conducive to the wetting and infiltration of electrolyte in water-based supercapacitors. At the same time, cation vacancies generate a large number of defects as active sites for energy storage. As a result, the specific capacity of the NiCoAl-OH electrode after 10,000 cycles can be maintained at 94.1%, which is much better than the NiCoAl-LDH material of 74%.
水滑石最早发现于天然矿石中，在超级电容器中具有重要应用。镍钴铝层状双氢氧化物（NiCoAl-LDH）作为一种结晶性良好的类水滑石化合物，通常通过水热法合成。Al3+在水滑石的结晶过程中起着重要作用，能提供稳定的三价阳离子，有利于水滑石的形成。然而，铝及其氢氧化物在强碱性电解质中不稳定；因此，本工作提出进行二次碱处理以产生阳离子空位。具有阳离子空位的NiCoAl-OH表面亲水性大大提高，有利于水系超级电容器中电解质的润湿和渗透。同时，阳离子空位产生大量作为储能活性位点的缺陷。结果，经过10000次循环后，NiCoAl-OH电极的比电容可保持在94.1%，远优于74%的NiCoAl-LDH材料。
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