【作者】 罗海峰； 聂平； 李洪森； 朱窈瑶； 张校刚；

【Author】 Haifeng Luo;Ping Nie;Hongsen Li;Yaoyao Zhu;Xiaogang Zhang;College of Material Science and Engineering,Nanjing University of Aeronautics and Astronautics;

【机构】 南京航空航天大学；

【摘要】 尖晶石型LiNi0.5Mn1.5O4(LNMO)具有电位高、能量密度大、倍率特性好、价格低廉等优点,是下一代最有潜力的锂离子电池正极材料之一[1]。研究表明,高的比表面积和丰富的孔道结构可以显著提高电极材料的电荷转移动力学、离子扩散速率及储锂性能,进而提高材料的放电比容量和循环稳定性。D-麦芽糖中含有八个羟基,当作为添加剂时,其浓度的高低可以控制反应物氧化还原反应的速率,抑制产物快速成核,因而可以较好地控制产物的形貌、结构和尺寸[2]。本文以D-麦芽糖为添加剂,采用低温溶剂热法制备了椭圆形α-Mn2O3(Fig.1a),并以其为锰源,以LiOH/Li2CO3(摩尔比0.74:0.26)为锂源,采用熔盐法制备分级结构LNMO纳/微球。从SEM图可以明显看出,得到的LNMO保持了前驱体形貌,且粒径有所减小,是由100 nm左右的纳米颗粒自组装而成(Fig.1b)。电化学测试表明(Fig.2),LNMO具有优异的倍率特性和循环稳定性,在1 C电流密度下循环100圈后容量保持率为89.5%。更多还原

【Abstract】 High-voltage LiNi0.5Mn1.5O4 spinel cathode material has received tremendous research interest due to the advantages of high discharge voltage(ca.4.7 V),low cost,and environmentally benign properties.In this work,oval-shape hierarchically structure LNMO has been synthesized via a facile molten salt method using α-Mn2O3 as precursors,which have been obtained by hydrothermal treatment of D-maltose molecule and manganese source.Scanning electron microscopy images revealed that the as-prepared oval-shape LNMO are constructed with nanometer-sized primary particles with sizes of approximately 100 nm.Electrochemical test results indicate that the unique morphology and porous structure can significantly improve the discharge capacity and cycling stability of LNMO material.The resultant product demonstrates superior rate capability and excellent cycling stability with 89.5% capacity retention over 100 cycles at a current density of 1 C.更多还原