Phase formation and crystallization of LiMn_(x)Fe_(1-x)PO_(4)-C olivine material with different Mn^(2+)contents fabricated at lower calcination temperatures

作     者：Guan-Wei Liu Xiang-Jun Zhang Song Gong Dan-Ping Jiang Bing-Xue Liu Rong Yang Shi-Gang Lu Guan-Wei Liu;Xiang-Jun Zhang;Song Gong;Dan-Ping Jiang;Bing-Xue Liu;Rong Yang;Shi-Gang Lu

作者机构：R&D center for energy storage and vehicle batteriesGeneral Research Institute for Nonferrous MetalsBeijing100088China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2022年第41卷第9期

页      面：3142-3149页

核心收录：

学科分类：0808[工学-电气工程] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0702[理学-物理学] 

基　　金：financially supported by the National Natural Science Foundation of China(No.51202014) 

主　　题：Energy storage materials Solid-state reactions Phase transitions 

摘      要：LiMn_(x)Fe_(1-x)PO_(4)-C cathode materials for lithium ion batteries were synthesized via solid-state method using Li_(2)CO_(3),MnCO_(3),NH_(4)H_(2)PO_(4),FePO_(4) and sucrose as starting raw materials,followed by high-temperature reduction-annealing.A series of calcination experiments at different temperatures reveal that Mn^(2+)-containing materials exhibit a lower temperature for olivine phase formation,for example LiMn_(0.5)Fe_(0.5)PO_(4) olivine phase forms at 275℃,while manganese-free crystalline LiFePO_(4) generally forms at the required temperature of 350℃.Increasing Mn^(2+) content is found to enhance crystallization degree of LiMn_(x)Fe_(1-x)PO_(4) material prepared at lower calcination temperatures.X-ray photoelectron spectroscopy(XPS)results confirm that Mn valence state(+2)remains unchanged up to~250℃ when calcined in ambient *** above-mentioned beneficial effect of manganese on phase formation and crystallization of olivine can be well attributed to the stable nature of Mn^(2+)and its strong propensity to form olivine phases.