Structural Feature and Electrochemical Performance of h-LiMnBO3 and Its Carbon Coated Material Prepared by Microwave Synthesis

摘要:

采用微波合成法制备了LiMnBO3及其碳包覆材料LiMnBO3/C。考察了烧结温度和配料比对LiMnBO3结构的影响。利用XRD、SEM、HR-TEM对材料的结构和形貌进行了表征。通过恒电流充/放电性能及交流阻抗测试研究了材料的电化学性能。结果表明，实验所得LiMnBO3具有六方晶体结构（即制得h-LiMnBO3）。750 ℃烧结温度下，反应25 min，且nLi:nB:nMn=1:1:1时，材料结晶较为完善、晶粒细小、形貌规整。碳包覆后材料充/放电性能及电导率均有提高。LiMnBO3/C的初次放电比容量达到50.3 mAh/g

Abstract:

LiMnBO3 and its carbon coated material LiMnBO3/C were synthesized by a microwave method. The influences of sintering temperature and feed composition on the structure and the morphology of materials were investigated. XRD, SEM and HR-TEM were used to characterize the structure and the morphology of the materials. The electrochemical properties of materials were tested by constant charge-discharge and electrochemical impedance spectroscopy. The results show that LiMnBO3 has a hexagonal crystal structure (h-LiMnBO3). The good crystalline structure with small grain size can be obtained under the reaction conditions of 750 oC, 25 min and nLi:nB:nMn=1:1:1(molar ratio). The charge-discharge capacity and the conductivity of the carbon coated material are enhanced after carbon coating. The initial discharge capacity of LiMnBO3/C is 50.3 mAh/g