Investigation on the effect of Na doping on structure and Li-ion kinetics of layered LiNi_0.6Co_0.2Mn_0.2O₂ cathode material

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• 作者：Zhenjun Huang^a ; Zhixing Wang^a ; ^{zxwang.csu@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Qun Jing^b ; Huajun Guo^a ; Xinhai Li^a ; Zhihua Yang^c ; ^{zhyang@ms.xjb.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Lithium-ion Batteries ; Na-doping ; Rate capabilty ; Li-ion diffusion coefficient ; First-principle calculation
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：20 February 2016
• 年：2016
• 卷：192
• 期：Complete
• 页码：120-126
• 全文大小：2547 K

文摘

Introducing the Na ion into the Ni-rich LiNi_0.6Co_0.2Mn_0.2O₂, Li_1-xNa_xNi_0.6Co_0.2Mn_0.2O₂ (x = 0, 0.01, 0.03) has been synthesized by high-temperature solid method. The effect of Na dopants on the structure, morphology, electrochemical properties, Li ion diffusion coefficient and the activation barriers has been extensively studied. Rietveld refinement results reveal that Na doping suppress cation mixing degree effectively and enlarge Li slab space. Electrochemical testing shows that Na-doped electrodes exhibit higher initial coulombic efficiency, good capacity retention and superior rate capability. Using experiments combined with first-principles calculations, we confirmed that the Na doping has enlarged Li slab space and then made the activation barrier of Li migration be reduced resulting higher Li⁺ diffusion coefficients.