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Effect of Film Thickness of Layer-Structured Oxide Thin Films on Lithium Insertion/Extraction and Semiconductive Properties

层状氧化物薄膜的膜厚对锂嵌入/脱嵌和半导体性能的影响

基本信息

批准号：
10650803
负责人：
NISHINA Tatsuo
金额：
$ 2.56万
依托单位：
YAMAGATA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

LiMィイD2xィエD2OィイD2yィエD2 (M=Mn, Ni, Co) thin films were fabricated by dipping Au wire into the citric complex during the synthesis process (DICC method). Only the LiCoOィイD22ィエD2 thin film was obtained by the in situ oxidation in molten carbonate. However, DICC process enabled us to fabricate the LiCoOィイD22ィエD2, LiMnィイD22ィエD2OィイD24ィエD2 and LiNiOィイD22ィエD2 thin films onto the Au. In case of LiCoOィイD22ィエD2 and LiNiOィイD22ィエD2 thin films, lithium extraction was easy but hard to insert lithium it. On the other hand, lithium extraction/insertion was quite easy for LiMnィイD22ィエD2OィイD24ィエD2 thin film up to 1 V/s scan rate in cyclic voltammetry with excellent cyclability. This result is really amazing that the charging/discharging rate of theoretical capacity within 10 seconds is possible principally but the recent state-of-the-art battery technology needs an hour. However, similar reversible charging/discharging reaction was obtained at very slow scan rate (0.01 mV/s) when the composite electrode o … More f LiMnィイD22ィエD2OィイD24ィエD2 was applied. This difference is a clear indication that the carbon conductive additive in the composite electrode enhances the electronic conductivity of active materials and passivated film formed on the Al current collector. However, it makes no potential gradient inside the active material, and hence it reduces the lithium ion conduction inside the solid phase. In case of thin film electrode, potential difference between electrolyte solution and current collector exists at the active material, and this enhances the lithium ion conductivity inside the active material solid phase.Optical current measurements were carried out using lock-in amplifier synchronized with the optical chopper. Unfortunately, we could not observe any traces of optical current. However, the formation of barrier type AlFィイD23ィエD2 passivation film was found at the Al current collector in the organic solution with LiPFィイD26ィエD2 and LiBFィイD24ィエD2 electrolyte by the high-potential field mechanism, which was similar to the anodic oxide film formation in aqueous solution. Less

在合成过程中，通过在柠檬酸络合物中浸渍Au丝的方法制备了LiMィイD2XィエD2OィイD2yィエD2(M=Mn，Ni，Co)薄膜。在熔融碳酸盐中原位氧化只得到了LiCoOィイD22ィエD2薄膜。然而，我们能够在Au上制备LiCoOィイD22ィエD2、LiMnィイD22ィエD2OィイD24ィエD2和LiNiOィイD22ィエD2薄膜。在LiCoOィイD22ィエD2和LiNiOィイD22ィエD2薄膜的情况下，锂的提取很容易，但很难插入锂。另一方面，在循环伏安实验中，LiMnィイD22ィエD2OィイD24ィエD2薄膜在高达1V/S的扫描速率下，锂的提取/插入相当容易，具有良好的循环性能。这个结果真的很令人惊讶，理论容量的充放电速度在10秒内是可能的，但最近最先进的电池技术需要一个小时。然而，当复合电极为…时，在很慢的扫描速度(0.01mV/S)下也得到了类似的可逆充放电反应使用更多的ィイD22ィエD2OィイD24ィエD2。这一差异清楚地表明，复合电极中的碳导电剂提高了铝集电体上形成的活性材料和钝化膜的电子导电性。然而，它在活性材料内部不会产生电位梯度，因此它降低了固相内的锂离子传导。对于薄膜电极，在活性物质处存在电解质溶液和集电体之间的电势差，从而提高了活性材料固相内的锂离子电导率。不幸的是，我们没有观察到任何光学电流的痕迹。而在含LiPFィイD26ィエD2和LiPFィイD24ィエD2电解液的有机溶液中，铝集电体上的AlFィイD23ィエD2钝化膜是通过高场机制形成的，这与水溶液中的阳极氧化膜的形成类似。较少