Wang J W, Yuan Y F, Zhang D, Zhu M, Mo C L, Guo S Y
College of Machinery and Automation, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China.
Hang Zhou City of Quality and Technical Supervision and Testing Institute, Hangzhou 310019, People's Republic of China.
Nanotechnology. 2021 Aug 2;32(43). doi: 10.1088/1361-6528/ac15cb.
Herein, we successfully synthesize MnOmultishelled hollow nanospheres through simply oxidizing Mn-based metal-organic framework microspheres. The number of the shells reaches 4. Many cavities and nanograins are hidden underneath the shell. The multishelled hollow structure brings about a wide hierarchical mesopore size range, large pore volume (0.26 cmg) and high specific surface area (117.6 mg). The superior zinc-ion storage performance may be achieved. The reversible capacity reaches 453 mAh gat current density of 0.1 A g. After 500 cycles at 1 A g, the discharge capacity of 152.8 mAh gis still delivered. The discharge capacity at 1.5 A gstabilizes at 107 mAh g. The zinc storage process is further studied through kinetics analyses. It is found that in the zinc storage process, ion diffusion process and capacitive process occur simultaneously, and the capacitive process is dominant. The excellent electrochemical performance is mainly attributed to the multishelled hollow nanosphere structure of MnO. This structure promotes contact of electrode materials/electrolyte, offers more active sites, facilitates infiltration of electrolyte, buffer volume change of MnO, improving electrochemical activity, reaction kinetics and cycling performance of MnO. Overall, MnOmultishelled hollow nanosphere is an excellent cathode material for aqueous zinc-ion batteries.
在此，我们通过简单地氧化锰基金属有机框架微球成功合成了MnO多壳空心纳米球。壳的数量达到4个。在壳的下面隐藏着许多空洞和纳米颗粒。多壳空心结构带来了宽范围的分级介孔尺寸、大的孔体积（0.26 cm³/g）和高的比表面积（117.6 m²/g）。可以实现优异的锌离子存储性能。在0.1 A/g的电流密度下，可逆容量达到453 mAh/g。在1 A/g下循环500次后，仍能提供152.8 mAh/g的放电容量。在1.5 A/g下的放电容量稳定在107 mAh/g。通过动力学分析进一步研究了锌存储过程。发现在锌存储过程中，离子扩散过程和电容过程同时发生，且电容过程占主导。优异的电化学性能主要归因于MnO的多壳空心纳米球结构。这种结构促进了电极材料/电解质的接触，提供了更多的活性位点，有利于电解质的渗透，缓冲了MnO的体积变化，提高了MnO的电化学活性、反应动力学和循环性能。总体而言，MnO多壳空心纳米球是水系锌离子电池的一种优异正极材料。
