Analysis and Application on the Functions of Oxide/Carbon Hetero-Junctions during Electrochemical Insertion/Extraction

锂二次电池铝集流体在含氟有机电解质溶液中形成致密的高场钝化膜。然而，这种钝化膜和铝基板的腐蚀增加了漏电流，降低了电池性能。在此基础上，研究了铝箔纯度、表面处理、复合阴极压制条件、电解液组成以及电池制造过程中化成工艺对集流体钝化膜的控制。很明显，通过向铝集流体中添加一些额外的金属杂质来降低钝化膜的漏电流，通过对铝进行表面加热，通过向阴极复合材料中添加少量的水，并通过加入氧供体如水和/或LiNO_3，5V级锂二次电池正极材料的研究是近年来的一个发展趋势。然而，阴极集电器的钝化膜特性仍然不是众所周知的。研究了锂二次电池有机电解液中某些阀金属在如此高的阳极电位下的阳极钝化行为。综上所述，5V级锂二次电池应使用铝作为正极集流体，因为铝在金属表面形成了高绝缘膜，具有高耐受电压。综上所述，集流体上钝化膜/碳导电添加剂的异质接触控制了正极的接触电阻。并且这控制锂二次电池的锂插入/脱嵌的总充电/放电速率。

Aluminum current collector of lithium secondary batteries forms compact passivated film according to the high field model in the organic electrolyte solutions including fluorine element. However, the corrosion of this passivated film and aluminum substrate increases the leak current and reduces the battery performance. Based on these points of view, the controlling of passivated film at aluminum current collector has been investigated as functions of aluminum foil purity, surface treatment, composite cathode pressing condition, electrolyte composition, and formation in the battery fabrication processes. It was clear that the charging/discharging cycle performance was improved by reducing leak current of passivated film by adding some additional metal impurities to the aluminum current collector, by applying surface heating of aluminum, by adding small amount of water to the cathode composite, and by adding oxygen donor such as water and / or LiNO_3 to the electrolyte solution.Research on cathode materials for 5 V class lithium secondary batteries is a trend in recent researches. However, the passivated film characteristic of a cathode current collector is still not well known. We investigated the anodic passivation behavior of some valve metals at such high anodic potentials in organic electrolytes for lithium secondary batteries. As a conclusion, we should use aluminum as a cathode current collector for 5 V class lithium secondary batteries since it formed a high insulating film with high tolerant voltage at the metal surface.In conclusions, Hetero-contact of passivated film on the current collector/carbon conductive additives controls the contacting resistance of the positive electrode, and this controls the total charging/discharging rate of lithium insertion/deinsertion of lithium secondary batteries.