Preparation and electrochemical properties of Ca-doped Li₄Ti₅O₁₂ as anode materials in lithium-ion battery

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• 作者：Qianyu Zhang^a ; Chengli Zhang^a ; Bo Li^a ; Shifei Kang^a ; Xi Li^a ; ^{xi_li@fudan.edu.cn} ; Yangang Wang^b ; ^{ygwang8136@gmail.com}
• 关键词：Lithium titanate ; Anode material ; Doping ; Lithium-ion battery
• 刊名：Electrochimica Acta
• 出版年：2013
• 出版时间：30 May, 2013
• 年：2013
• 卷：98
• 期：Complete
• 页码：146-152
• 全文大小：1741 K

文摘

Ca-doped lithium titanates with the formula of Li_4?xCa_xTi₅O₁₂ (x = 0, 0.05, 0.1, 0.15, 0.2) were synthesized as anode materials by a simple solid-state reaction in an air atmosphere. The phase structure, morphologies and electrochemical properties of the prepared powders were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. XRD revealed that the Ca-doping caused no change on the phase structure and highly crystalline Li_4?xCa_xTi₅O₁₂ (0 ¡Ü x ¡Ü 0.2) powders without any impurity were obtained. SEM images showed that all samples had similar particulate morphologies and the particle size distribution was in the range of 1-2 ¦Ìm. It was observed that Ca-doped lithium titanates employed as the anode materials of lithium-ion batteries delivered excellent electrochemical performances, and sample Li_3.9Ca_0.1Ti₅O₁₂ exhibited a higher specific capacity, better cycling performance and rate capability than other samples. The Li_3.9Ca_0.1Ti₅O₁₂ material showed discharge capacities of 162.4 mAh g^?1, 148.8 mAh g^?1 and 138.7 mAh g^?1 after 100 cycles at 1 C, 5 C and 10 C charge-discharge rates, respectively. Electrochemical impedance spectroscopy (EIS) revealed that the Li_3.9Ca_0.1Ti₅O₁₂ electrode exhibited the highest electronic conductivity and fastest lithium-ion diffusivity, which indicated that this novel Li_3.9Ca_0.1Ti₅O₁₂ material was promising as a high-rate anode material for the lithium-ion batteries.