Improving rate capacity and cycling performance of lithium-rich high-Mn Li_1.8[Mn_0.7Co_0.15Ni_0.15]O_2.675 cathode materials by Li₂SiO₃ coating

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• 作者：Kai Gao^a ; ^b ; Shi-Xi Zhao^a ; ^{zhaosx@sz.tsinghua.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Shuang-Tao Guo^a ; ^b ; Ce-Wen Nan^b
• 关键词：Lithium ion batteries ; Lithium-excess high manganese layered oxides ; Cathode materials ; Carbonate co-precipitation method ; Li2SiO3 Coating
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 July 2016
• 年：2016
• 卷：206
• 期：Complete
• 页码：1-9
• 全文大小：4719 K

文摘

Spherical lithium-excess high manganese layered oxides, Li_1.8[Mn_0.7Co_0.15Ni_0.15]O_2.675, were successfully synthesized by carbonate co-precipitation method. To further improve the electrochemical performance of this cathode materials, spherical Li_1.8[Mn_0.7Co_0.15Ni_0.15]O_2.675 particles were functionally modified with fast Li⁺-ion conductor Li₂SiO₃ via a sol-gel method. The structural change features were systematically characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, scanning electron microscopy, cyclic voltammograms and electrochemical impedance spectroscopy. The results show that Li₂SiO₃ coating layer can greatly improves the diffusion rate of Lithium ions at the interface between cathode materials and electrolyte, Li_1.8[Mn_0.7Co_0.15Ni_0.15]O2.675@Li₂SiO₃ composite cathode materials exhibits outstanding rate capability(*), cycle stability and low polarization. This excellent performance is attributes to Li₂SiO₃ coating layer can prevent electrode from the corrosion of electrolyte and improve the diffusion rate of lithium ion. 1.5 wt% Li₂SiO₃ coating sample shows the highest rate capacity (approximately 250 mAh g⁻¹ at 0.1C and 160 mAh g⁻¹ at 1C) and stable cyclic performance when cycled between 2.5-4.8 V at 25 °C.