1.Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China 2.College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin 150001, China 3.Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China 4.Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 11704089, 51672056), the Natural Science Foundation of Heilongjiang Province, China (Grant No. LH2020E093), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province, China (Grant No. UNPYSCT-2018216), the China Postdoctoral Science Foundation (Grant No. 2017M611355), Fundamental Research Funds for the Central Universities (Grant No. 3072021CFT0402), and Merit-based funding for returning overseas students in Heilongjiang Province
Received Date:15 December 2020
Accepted Date:25 March 2021
Available Online:07 June 2021
Published Online:20 August 2021
Abstract:In recent years, the cathode materials of magnesium ion batteries have become a hot point of research, and the improvement of high-rate performance and cycle stability has become the main research goal. In this paper, sodium manganese oxide (Na0.55Mn2O4·1.5H2O) nanomaterial with a blended structure of nanowires and nanosheets is prepared by the hydrothermal method. The structure and morphology of the material are analyzed by X-ray diffraction and scanning electron microscopy. The variable rate charge-discharge curves and variable scan rate cyclic voltammetry curves are obtained by a battery tester and electrochemical workstation, respectively. The results show that the hydrothermal reaction time has significant effects on phase structure and morphology composition of the material. The nanosheets and nanowires in the sample form a closely blend by 72-h hydrothermal reaction (NMO-72), and the nanosheets effectively fill into the intersecting space of the nanowires. In this way, the tap density of the material is improved. More importantly, NMO-72 has higher discharge specific capacity and rate cycling performance. At a current density of 50 mA·g–1, the discharge specific capacity of NMO-72 reaches 229.1 mAh·g–1. At a current density of 1000 mA·g–1, the discharge specific capacity of the NMO-72 stabilizes at 81 mAh·g–1. When the current density returns to 50 mA·g–1 again, the discharge specific capacity remains stable at 164.7 mAh·g–1. Besides, the cyclic voltammetry test shows that the NMO-72 material has more excellent magnesium ion diffusion kinetic performance than other materials. Therefore, the NMO-72 material has more excellent reversible specific capacity, high rate performance and cycling stability. Keywords:aqueous Mg-ion batteries/ cathode materials/ sodium manganese oxides/ electrochemical performance
图 1 制备样品的XRD曲线
图 2 制备样品的SEM照片 (a) NMO-60; (b) NMO-72; (c) NMO-84. 插图为局部放大的SEM照片
图 3 制备样品的EDS图片
图 4 制备样品在不同倍率下的充放电循环性能
图 5 不同倍率下的充放电曲线 (a) NMO-60; (b) NMO-72; (c) NMO-84
图 6 不同扫描速率下的循环伏安曲线 (a) NMO-60; (b) NMO-72