Zhou Jiachao, Wang Yingchao, Zhou Jiaojiao, Chen Kang, Han Lei
State Key Laboratory Base of Novel Functional Materials and Preparation Science, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
Dalton Trans. 2021 Nov 2;50(42):15129-15139. doi: 10.1039/d1dt02666f.
Reasonable design of electrodes with well-defined nanostructure is the central aspect in the practical application of high-performance supercapacitors. Herein, hollow tube@sheets NiCoS core-shell nanoarrays are rationally constructed to the free-standing electrode by growing ZIF-67 on Co-precursor nanorods array and sequentially performing anion-exchange (S) and cation-exchange (Ni). The well-defined nanostructures can shorten the ion transport path in the charging-discharging process, increase the specific surface area and electrochemical active cites, which help in improving electrochemical performance. Therefore, the unique tube@sheets NiCoS core-shell nanoarrays exhibit intriguing electrochemical performance and show excellent areal capacitance of 11.3 F cm (3227.94 F g) at a current density of 2 mA cm (2 A g). The assembled asymmetric supercapacitor device delivers a high energy density of 0.42 mW h cm at a power density of 2.1 mW cm and displays outstanding cyclic stability (90.2% retention after 5000 cycles). Consequently, the well-defined nanostructure engineering strategy is beneficial for designing active electrode materials for efficient energy storage devices.
合理设计具有明确纳米结构的电极是高性能超级电容器实际应用的核心方面。在此，通过在钴前驱体纳米棒阵列上生长ZIF-67并依次进行阴离子交换（S）和阳离子交换（Ni），合理构建了中空管@片层NiCoS核壳纳米阵列作为独立电极。明确的纳米结构可以缩短充放电过程中的离子传输路径，增加比表面积和电化学活性位点，有助于提高电化学性能。因此，独特的管@片层NiCoS核壳纳米阵列表现出引人注目的电化学性能，在2 mA cm（2 A g）的电流密度下显示出11.3 F cm（3227.94 F g）的优异面积电容。组装的不对称超级电容器装置在2.1 mW cm的功率密度下提供0.42 mW h cm的高能量密度，并显示出出色的循环稳定性（5000次循环后保留率为90.2%）。因此，明确的纳米结构工程策略有利于设计用于高效储能装置的活性电极材料。
