Mn3O4微观结构对固相合成类单晶锰酸锂的影响

探究了Mn₃O₄的微观结构对高温固相法制备类单晶锰酸锂(LiMn₂O₄)的影响。结果表明，前驱体对LiMn₂O₄的结构和形貌有决定性的影响。粒度小、比表面积大的类球形Mn₃O₄更易制得类单晶锰酸锂，其颗粒团聚致密、表面光滑，且晶胞参数小、能量密度大、Li⁺浓度高。类单晶锰酸锂的综合电化学性能和热稳定性远高于非类单晶材料，在0.2 C倍率下首次放电比容量和库仑效率分别高达112.50 mA·h/g、96.5%,8 C倍率下放电比容量仍有102.11 mA·h/g,200次循环后容量保持率为90.1%。类单晶锰酸锂优异的性能归因于其具有稳定的晶体结构和外露表面、较高的Li⁺浓度，在电化学反应中结构稳定、锂离子迁移速率快、电极极化和电荷转移阻抗小。

Effect of Mn3O4 microstructure on solid-phase synthesis of mono-like lithium manganate

The influence of the microstructure of Mn3O4 on the preparation of mono-like lithium manganate by high temperature solid state reaction. The experimental results show that the precursors have a great influence on the structure and morphology of LiMn2O4. Mono-like lithium manganate, which has dense particle agglomeration, smooth surface, and small cell parameters, high density, and Li-ion molar concentration, is easily made by sphere-like Mn3O4 with small particle size and large specific surface area. The comprehensive electrochemical performanced and thermal stability of the mono-like lithium manganate is excellent and much higher than that of general lithium manganate materials, such as the first discharge specific capacity of 112.50 mAh/g and the coulomb efficiency at 0.2C of 96.5%; the discharge specific capacity is still as high as 102.11 mAh/g at 8C rate, as well as the capacity retention of 90.1% after 200 cycles at 1C. The excellent performance of single crystal lithium manganate is attributed to its more stable crystal structure, larger exposed surface, and higher li-ion molar concentration, but also exhibits higher charge-discharge reversibility, faster li-ion migration rate, lower electrode polarization and charge transfer impedance in electrochemical reactions.