Abstract

In this study, the spray-drying technique was used to apply a 0.5 at%, 1 at%, and 1.25 at% of lithium lanthanum zirconium tantalum oxide (Li_6.75La₃Zr_1.75Ta_0.25O₁₂) powder coating on the surface of lithium cobalt oxide (LiCoO₂) cathode materials. Subsequently, these materials were sintered for either 5 or 10 h at 800 °C to obtain LiCoO₂ cathode materials with a rough coating. X-ray diffraction, cyclic voltammetry, electrochemical impedance spectroscopy, and differential scanning calorimetry were then conducted to analyze differences in the structure, electrochemical properties, and thermostability of the materials before and after surface modification. The modified LiCoO₂ cathodes with Li_6.75La₃Zr_1.75Ta_0.25O₁₂ rough coating had more than twice the discharge capacity as the bare LiCoO₂ cathode at a high discharge current density when the cutoff voltage ranged from 2.8 to 4.5 V. In addition, 1 at% Li_6.75La₃Zr_1.75Ta_0.25O₁₂ coating and 5 h of sintering at 800 °C resulted in the optimal capacity retention of 85.4% after 80 cycles and a slower exothermic reaction than that of the bare LiCoO₂ cathode. Thus, rough coating an adequate quantity of Li_6.75La₃Zr_1.75Ta_0.25O₁₂ powder on a LiCoO₂ cathode mitigated the reaction between the cathode material surface and electrolyte, stabilizing the main structure and enhancing the ionic conductivity and electrochemical characteristics of the material.

中文翻译：

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通过对锂镧锆钛酸钽进行粗糙涂覆来修饰LiCoO 2以获得锂离子电池的高压性能

摘要

在这项研究中，使用喷雾干燥技术在锂离子电池表面喷涂了0.5 at％，1 at％和1.25 at％的锂镧锆钽氧化物（Li _6.75 La ₃ Zr _1.75 Ta _0.25 O ₁₂）粉末涂料。锂钴氧化物（LiCoO ₂）正极材料。随后，将这些材料在800°C下烧结5或10 h，以获得LiCoO ₂阴极材料，涂层粗糙。然后进行了X射线衍射，循环伏安法，电化学阻抗谱和差示扫描量热法，以分析表面改性前后材料的结构，电化学性质和热稳定性的差异。当截止电压在2.8至4.5 V范围内时，在高放电电流密度下，具有Li _6.75 La ₃ Zr _1.75 Ta _0.25 O ₁₂粗糙涂层的改性LiCoO ₂阴极具有比裸LiCoO ₂阴极大两倍的放电容量。 ，1 at％Li _6.75 La ₃ Zr _1.75Ta _0.25 O ₁₂涂层和在800°C烧结5 h在80个循环后的最佳容量保持率为85.4％，并且放热反应比LiCoO ₂裸阴极慢。因此，在LiCoO ₂阴极上粗涂适量的Li _6.75 La ₃ Zr _1.75 Ta _0.25 O ₁₂粉末可减轻阴极材料表面与电解质之间的反应，稳定主结构并增强材料的离子电导率和电化学特性。 。