In situ Sr2+-doped spinel LiNi0.5Mn1.5O4 cathode material for Li-ion batteries with high electrochemical performance and its impact on morphology
In situ Sr2+-doped spinel LiNi0.5Mn1.5O4 cathode material for Li-ion batteries with high electrochemical performance and its impact on morphology
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DOI：
10.1016/j.ceramint.2021.08.093
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发表时间：
2021-08
影响因子：
5.2
通讯作者：
X. Ji;Dai Xinyi;Fuzhong Wu;M. Yi;Haijun Chen;Yi-Jing Gu
中科院分区：
文献类型：
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作者：
X. Ji;Dai Xinyi;Fuzhong Wu;M. Yi;Haijun Chen;Yi-Jing Gu
LiNi0.5Mn1.5O4(LNMO)是一种很有前景的下一代高能量密度锂离子电池正极材料，但由于其在高电压下与电解液固有的副作用，即严重的Mn溶解和容量衰减，其应用受到阻碍。采用溶胶-凝胶法成功制备了新型LiNi0.5Mn1.5-xSrxO4材料（x = 0、0.05、0.1、0.15和0.2），并研究了不同原位Sr2+掺杂对晶体结构、形貌和电化学性能的影响。一系列表征表明，Sr掺杂的LNMO结构含有较少的Mn3+，从而增强了其循环稳定性。此外，Sr掺杂更显着地促进形貌变化。随着(100)面的出现，LNMO的形貌从八面体转变为截角八面体。 (100)表面可以有效抑制与电解质的副反应，并在工作电压下稳定结构，这也有助于支持Li+传输动力学。 Sr掺杂的LiNi0.5Mn1.4Sr0.1O4（表示为LNMO-Sr0.1）正极表现出优异的循环稳定性，在1C下循环500次后，容量保持率为86.63%。 CV和EIS结果表明，适量的Sr掺杂有效降低了电极极化和电荷转移电阻，并提高了Li+扩散系数。
LiNi0.5Mn1.5O4(LNMO) is a promising next-generation cathode material for high energy density lithium-ion batteries, but the application of LNMO is blocked because of its inherent side effects with electrolytes at high voltages, namely, serious Mn dissolution and capacity attenuation. A novel LiNi0.5Mn1.5-xSrxO4material (x = 0, 0.05, 0.1, 0.15, and 0.2) was successfully prepared using the sol-gel method, and the effect of varying in situ Sr2+-doping on the crystal structure, morphology, and electrochemical performance was researched. A series of characterizations showed that the Sr-doped LNMO structure contains less Mn3+, which enhances its cycling stability. In addition, Sr doping promotes morphological changes more remarkably. Accompanied by the appearance of (100) surfaces, the morphology of LNMO changes from an octahedron to a truncated octahedron. The (100) surface can effectively inhibit side reactions with the electrolyte and steady the structure at the working voltage, which also helps support Li+transport kinetics. The Sr-doped LiNi0.5Mn1.4Sr0.1O4(expressed as LNMO-Sr0.1) cathode exhibits preeminent cycling stability, after 500 cycles at 1C, the capacity retention is 86.63 %. CV and EIS results show that the right amount of Sr doping efficiently reduces electrode polarization and charge transfer resistance and increases the Li+diffusion coefficient.