摘要
橄榄石型LiFePO_(4)材料因其高理论容量(170 mAh/g)、优异的热稳定性、环境友好和低成本等优点而成为目前动力电池主要正极材料。然而,LiFePO_(4)较低的工作电压(3.4 V vs.Li+/Li)导致其能量密度不高,同样具有橄榄石型结构的LiMnPO_(4)的工作电压达到4.1 V,因而具有更高的能量密度,可是LiMnPO_(4)的循环稳定性差。铁掺杂的LiFe_(0.4)Mn_(0.6)PO_(4)/C正极材料结合了LiFePO_(4)和LiMnPO_(4)的优点,具有高能量密度、良好的循环稳定性和安全性等优势,因而成为当今正极材料研究的热点材料之一。然而,要实现其大规模商业化应用,仍需进一步提高LiFe_(0.4)Mn_(0.6)PO_(4)/C材料的倍率性能和循环寿命。为了解决这些问题,研究人员发现构建多孔结构和碳包覆是最有效的方法之一。为此,采用葡萄糖辅助溶剂热法来构建多孔LiFe_(0.4)Mn_(0.6)PO_(4)/C材料。对比研究两种水热法来制备LiFe_(0.4)Mn_(0.6)PO_(4)/C材料,发现葡萄糖辅助溶剂热法能得到棒状、纳米结构的多孔LiFe_(0.4)Mn_(0.6)PO_(4)/C材料,并表现出优异的电化学性能。在0.1、0.2、0.5、1和2 C时,放电比容量分别达到140.1、130.6、118、106.1和88.9 mAh/g,在1 C倍率下充放电循环100次后保持率达94.7%。这说明在溶剂热法基础上加入一定量的葡萄糖辅助,可以调控制备多孔LiFe_(0.4)Mn_(0.6)PO_(4)/C纳米材料,并能显著改善其倍率性能和循环性能。
Olivine type LiFePO_(4)material has become the main positive electrode material for power batteries due to its high theoretical capacity(170 mAh/g),excellent thermal stability,environmental friendliness,and low cost.However,the relatively low operating voltage of LiFePO_(4)(3.4 V vs.Li+/Li)results in a lower energy density.In contrast,LiMnPO_(4),which has also an olivine type structure,operates at a higher voltage of 4.1 V,offering higher energy density,but it suffers from poor cycling stability.The iron doped LiFe_(0.4)Mn_(0.6)PO_(4)/C material combines the advantages of LiFePO_(4)and LiMnPO_(4),featuring high energy density,good cycling stability,and safety,making it one of the hottest materials in the cathode materials of lithium-ion batteries.However,to achieve large-scale commercial application,the rate performance and cycle life of LiFe_(0.4)Mn_(0.6)PO_(4)/C materials still need to be further improved.To address these issues,researchers have found that constructing a porous structure and carbon coating are among the most effective methods.To this end,a glucose assisted solvothermal method was used to prepare porous LiFe_(0.4)Mn_(0.6)PO_(4)/C materials in this content.A comparative study of two hydrothermal methods for preparing LiFe_(0.4)Mn_(0.6)PO_(4)/C materials revealed that glucose-assisted solvothermal method could construct rod-shaped and porous LiFe_(0.4)Mn_(0.6)PO_(4)/C nanostructure with excellent electrochemical performance.The discharge specific capacities at 0.1,0.2,0.5,1 and 2 C were 140.1,130.6,118,106.1 and 88.9 mAh/g,respectively.After 100 charge-discharge cycles at 1 C rate,the capacity retention reached 94.7%.This demonstrates that glucose-assisted solvothermal synthesis can effectively regulate the structure and morphology of the LiFe_(0.4)Mn_(0.6)PO_(4)/C,leading to significant improvements in its rate performance and cycling.
作者
刘樟斌
李济澜
LIU Zhang-bin;LI Ji-lan(School of Environmental and Chemical Engineering,Dalian University,Dalian 116622,China;School of Chemistry and Materials Engineering,Liupanshui Normal University,Liupanshui 553004,China)
出处
《化学试剂》
2025年第7期43-49,共7页
Chemical Reagents
基金
贵州省教育厅基金项目(黔教技[2023]044号)
贵州省科技厅技术基金项目(黔科合基础-ZK[2022]一般531)
六盘水师范学院高层次人才科研启动基金项目(LPSSYKYJJ202006)
六盘水师范学院联合培养研究生科研项目(LPSSYLPY202327)。
