Novel cathode material for lithium rechargeable battery : graphite intercaration compounds of some transition metal chlorides

一些过渡金属氯氯化物的石墨交错化合物（GIC）具有刚性分层结构和高电子导电性。In this study， electrochemical insertion of lithium into the GICs of some transition metal chlorides was investigated in order to apply the GICs to the cathode materials for lithium secondary batteries.The discharge and charge characteristics of a 1st stage GIC of cobalt dichloride， CイD25.5イエD2CoCイD2l2.2イD2， was investigated in various organic electrolytes containing 1 M LiClOイD24イD2。The kinds of organic electrolytes did not affect the potentials during insertion of lithium but the amounts of accommodated lithium in the GIC. GIC的X射线差异在锂的插入后显示了分层结构被破坏。Furthermore，从锂化GICs中提取的锂是几乎不可能的。The electrochemical lithiation behavior of a 4 th stage gIC of niobium pentachloride，C-D224-D2 NbCi-D25.2-D2， was investigated in 1 M LiClO-D24-D2 / PC electrolyte。GIC的分层结构被保留了从五分之二到四分之一的减少。However，从锂的GIC中提取锂是不可能的。Furthermore，从GIC不可逆转地减少到三重中的氯化物的释放，这些结果显示了两种钴和镍氯化物的GICs是不适合用于锂二级电池的氯化物材料的。However，有人建议，锂可以插入到含有过渡金属的较高阶段GICs中，因为它们可以在不破坏分层结构的情况下使用各种价值状态。

Graphite intercalation compounds (GIC) of some transition metal chlorides have rigid layered structures and high electronic conductivity. In this study, electrochemical insertion of lithium into the GICs of some transition metal chlorides was investigated in order to apply the GICs to the cathode materials for lithium secondary batteries.The discharge and charge characteristics of a 1st stage GIC of cobalt dichloride, CィイD25.5ィエD2CoCィイD2l2.2ィエD2, was investigated in various organic electrolytes containing 1 M LiClOィイD24ィエD2. The kinds of organic electrolytes did not affect the potentials during insertion of lithium but the amounts of accommodated lithium in the GIC. X-ray diffraction of the GIC showed that the layered structures were broken after insertion of lithium. Furthermore, the extraction of lithium from the lithiated GICs was almost impossible.The electrochemical lithiation behavior of a 4th stage GIC of niobium pentachloride, CィイD224ィエD2NbCiィイD25.2ィエD2, was investigated in 1 M LiClOィイD24ィエD2 / PC electrolyte. The layered structure of the GIC was preserved during reduction from pentavalent to tetravalent. However, the extraction of lithium from the lithiated GIC was impossible. Furthermore, the liberation of chloride ions from the GIC occurred irreversibly during reduction from tetravalent to trivalent.These results showed that the GICs of both cobalt and niobium chlorides are not suitable for cathode materials for lithium secondary batteries. However, it was suggested that lithium can be inserted into the higher stage GICs containing the transition metals which can take various valence states without destruction of the layered structures.