纳米Al2O3包覆富锂锰基正极材料Li1.2Ni0.13Co0.13Mn0.54O2的性能研究

采用纳米三氧化二铝(Al₂O₃)对富锂锰基正极材料Li_1.2Ni_0.13Co_0.13Mn_0.54O₂进行表面均匀包覆, 并考察了最优纳米Al₂O₃包覆量下材料的电化学性能. 扫描电子显微镜(SEM)和透射电子显微镜(TEM)显示了纳米Al₂O₃对富锂锰基正极材料表面均匀包覆, X射线衍射分析(XRD)结果表明包覆后富锂材料依然具有良好的层状结构. 恒流充/放电循环测试发现, 包覆后的Li_1.2Ni_0.13Co_0.13Mn_0.54O₂材料的首次放电比容量为249.7 mA·h/g, 循环100次后的容量保持率为89.5%, 与未包覆的Li_1.2Ni_0.13Co_0.13Mn_0.54O₂材料相比, 容量保持率提升约13%. 循环伏安(CV)和电化学阻抗(EIS)测试结果表明, 纳米Al₂O₃包覆可有效抑制材料极化, 降低界面阻抗和电荷转移阻抗, 进而提升富锂锰基正极材料的电化学性能.

Nano-Al2O3 Coated Li-rich Cathode Material Li1. 2Ni0.13Co0.13Mn0.54O2 for Highly Improved Lithium-ion Batteries †

The lithium-rich cathode material Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ were coated uniformly by nano-Al₂O₃ for highly stable lithium-ion batteries. The optimum content of nano-Al₂O₃ coating on the structure, surface morphology and electrochemical properties were systematically studied by X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). SEM and TEM results show that the surface of the lithium-rich cathode material is evenly coated with nano-Al₂O₃. XRD results show that the as-synthesized materials have a layered structure. Electrochemical test results show that the nano-Al₂O₃ coating is beneficial to improving the discharge specific capacity, rate performance and cycle stability. The nano-Al₂O₃ coated Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ material has a specific discharge capacity of 249. 7 mA·h/g with excellent cycling stability(89.5% capacity retention after 100 cycles). Cyclic voltammetry(CV) and electrochemical impedance(EIS) results show that nano-Al₂O₃ coating can effectively inhibit the erosion of HF, reduce electrode material/electrolyte interface side-reactions, decrease polarization, reduce interface impedance and charge transfer impedance. This work suggests that the nano-Al₂O₃ coating is an effective route to significantly improve the electrochemical performance of lithium-rich cathode materials.