Self-assembled α-MnO2 urchin-like microspheres as a high-performance cathode for aqueous Zn-ion batteries  

自组装α-MnO2海胆状微米球应用于水系锌离子电池的高性能阴极

作　　者：Yunzhao Wu Ye Tao Xianfu Zhang Kai Zhang Shengbin Chen Yu Liu Yong Ding Molang Cai Xuepeng Liu Songyuan Dai 吴云召;陶冶;张先付;张凯;陈盛斌;刘瑜;丁勇;蔡墨郎;刘雪朋;戴松元(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)

机构地区：[1]State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China

出　　处：《Science China Materials》2020年第7期1196-1204,共9页中国科学（材料科学（英文版）

基　　金：supported by the National Key Research and Development Program of China(2016YFA0202400);the 111 Project(B16016);the National Natural Science Foundation of China(51702096,U1705256 and 51572080);the Fundamental Research Funds for the Central Universities(2018ZD07 and JB2019132)。

摘　　要：Aqueous Zn-ion batteries(AZIBs)are one of the promising battery technologies for the green energy storage and electric vehicles.As one attractive cathode material for AZIBs,α-MnO2 materials exhibit superior electrochemical properties.However,their long-term reversibility is still in great suspense.Considering the decisive effect of the structure and morphology on theα-MnO2 materials,hierarchicalα-MnO2 materials would be promising to improve the cycle performance of AZIB.Here,we synthesized theα-MnO2 urchin-like microspheres(AUM)via a self-assembled method.The porous microspheres composed of one-dimensionalα-MnO2 nanofibers with high crystallinity,which improved the surface area and active sites for Zn2+intercalation.The AUM-based AZIB realized a high initial capacity of 308.0 mA hg-1,and the highest energy density was 396.7 W hkg-1.The kinetics investigation confirmed the high capacitive contribution and fast ion diffusion of the AUM.Ex-situ XRD measurement further verified the synergistic insertion/extraction of H+and Zn2+ions during the charge/discharge process.The superiority of the AUM guaranteed good electrochemical performance and reversible phase evolution,and this application would promote the follow-up research on the advanced AZIB.在绿色能源存储和电动汽车领域,水系锌离子电池(AZIB)是一种十分有潜力的电池技术.α-MnO2作为AZIB的一种热点正极材料,表现出十分优异的电化学性能.但是,α-MnO2正极的长期稳定性问题仍待解决.α-MnO2材料的结构和形貌会对其性能产生决定性的影响,因此构建多级结构的α-MnO2材料是一种提升AZIB循环充放电性能的可行方法.本文中,我们采用自组装法合成了一种α-MnO2海胆状微米球(AUM).这种微米球是由高度结晶的一维α-MnO2纳米线构建而成,这种疏松多孔的结构将有助于提升材料的比表面积和Zn2+离子嵌入的活性位点.基于AUM的AZIB器件实现了高达308.0 m A h g-1的初始容量,其最大能量密度可达396.7 W h kg-1.动力学分析表明,AUM正极具备较高比例的电容型容量贡献及快速离子扩散系数.非原位XRD测试进一步证实,在充放电过程中,存在H+和Zn2+离子的协同嵌入/脱嵌现象.AUM的这种优异特性,使器件实现了很好的电化学性能和循环可逆的结构相变,本工作将有助于高性能AZIB的进一步深入研究.

关 键 词：aqueous Zn-ion batteries α-MnO2 urchin-like microspheres fast ion diffusion coefficients reversible phase evolution synergistic H+-Zn2+insertion/extraction 

分 类 号：TM912[电气工程—电力电子与电力传动]