Electrochemical Studies of Substituted Spinel Thin Films
Electrochemical Studies of Substituted Spinel Thin Films
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取代尖晶石薄膜的电化学研究
DOI：
10.1149/1.1392640
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发表时间：
1999
影响因子：
3.9
通讯作者：
E. Cairns
中科院分区：
文献类型：
--
作者：
K. Striebel;A. Rougier;C. R. Horne;R. Reade;E. Cairns
采用脉冲激光沉积制备的锂锰氧化物尖晶石薄膜已被用作模型系统，用于研究在没有碳或粘合剂材料的情况下氧化物电化学性能和性能退化机制。 Li{sub x}Mn{sub 2{minus}y}Me{sub y}O{sub 4} 薄膜（0.3 {μm），其中 Me = Ni、Co 且 y = 0, 0.1, 0.25，是所制备的晶体。在液体电解质中，在 2 至 5.8 V vs. Li/Li{sup +} 的范围内测量作为氧化物组成函数的循环伏安响应。 x > 0.5 和 x < 0.5 的两个 4 V 峰的定量分析与预测的薄膜化学计量关系良好。 Ni取代薄膜中4.6 V氧化还原峰的容量与Ni{sup 2+}氧化成Ni{sup 4+}一致。在高于 4.5 V 的 LiMn{sub 2}O{sub 4} 中没有观察到显着的容量。3 V 区域中的伏安峰形状表明嵌入动力学因 Jahn-Teller 畸变而减慢，而 4 V 区域中的所有成分都显示出可逆行为，除了 LiNi{sub 0.25}Mn{sub 1.75}O{sub 4} 薄膜表现出较低的电子电导率。使用开窗循环伏安法将 LiMn{sub 1.90}Ni{sub 0.10}O{sub 4} 薄膜充电至 5.7 V（相对于 Li/Li{sup +}）后，放电容量没有损失。 LiMn{sub 2}O{sub 4} 和 LiMn{sub 1.75}Co{sub 0.25}O{sub 4} 薄膜相对于 Li/Li{sup +} 分别稳定在 5.6 和 5.4 V。研究了薄膜相对于粉末电极的优异稳定性的解释。« less
Thin lithium manganese oxide spinel films, prepared with pulsed laser deposition have been used as a model system for the study of oxide electrochemical properties and performance degradation mechanisms in the absence of carbon or binder materials. Films (0.3 {micro}m) of Li{sub x}Mn{sub 2{minus}y}Me{sub y}O{sub 4}, where Me = Ni, Co and y = 0, 0.1, 0.25, were crystalline as-prepared. The cyclic voltammetric response as a function of oxide composition was measured in liquid electrolyte over the range of 2 to 5.8 V vs. Li/Li{sup +}. Quantitative analysis of the two 4 V peaks, for x > 0.5 and x < 0.5, correlated well with predicted film stoichiometry. The capacity of the 4.6 V redox peaks in the Ni-substituted films were consistent with the oxidation of Ni{sup 2+} to Ni{sup 4+}. No significant capacity was observed in LiMn{sub 2}O{sub 4} above 4.5 V. The shape of the voltammetric peaks in the 3 V region suggested that intercalation kinetics are slowed by the Jahn-Teller distortion, while all compositions in the 4 V region showed reversible behavior, except for the LiNi{sub 0.25}Mn{sub 1.75}O{sub 4} film which showed lower electronic conductivity. The LiMn{sub 1.90}Ni{sub 0.10}O{sub 4} films showed no loss in discharge capacitymore » after being charged up to 5.7 V vs. Li/Li{sup +} with window-opening cyclic voltammetry. LiMn{sub 2}O{sub 4} and LiMn{sub 1.75}Co{sub 0.25}O{sub 4} films were stable to 5.6 and 5.4 V vs. Li/Li{sup +}, respectively. Explanations for the superior stability of the films relative to powder electrodes are examined.« less