| As the lightest metal (its density is 0.535×103 kg/m3), lithium metal is also with low electro negativity, its standard electrode potential is -3.045V (comparing hydrogen electrode). With many kinds of positive materials, lithium is able to composite different series of batteries, which usually possess high working voltage and energy density. Since the sixties in the last century, lithium battery is a hot research field. And many good battery systems were invented, such as Li-(CFx)n battery, Li-MnO2 battery, Li-SO2 battery, Li-SO2 battery, Li-SOCl2 battery, Li-CuO battery and Li-I2 battery, and so on. However, there still are many problems in these systems, two vital of which is insecurity and poor circularity that block the large scale commercial application.Since the putting forward of intercalation and de-intercalation theory and the preparation of positive material of LiCoO2 and negative material of graphite with layer structure, the usage of lithium metal as negative material was avoid, and the problem of short-circuit caused by the generation of lithium pine-tree crystal, and the insecurity and circularity were greatly improved. But lithium as negative material is also with some significant and non-substitutable characters, for example, the specific capacity is very high (about 3860mAh/g). Sometime, the usage of lithium battery is irreplaceable, for example, the usage of lithium-iodine battery is used as the power source for cardiac pacemaker applications. Therefore, in the long run, lithium ion battery maybe will be substituted by lithium battery.In this work, some research about iodine positive material I2-Lil (3-hydroxypropionitrile)2 is done as follows.1. The mixture of anhydrous of Lil and 3-hydroxypropionitrile (HPN) was heated until a homogeneous melt was obtained and then cooling to room temperature naturally, the crystal of Lil (3-hydroxypropionitrile)2 was obtained. Pure electrolyte material was got through recrystallization of above product with ethyl acetate. Heating the mixture of iodine and the material of electrolyte with different molar ratio, the positive material I2-LiI (HPN)2 was first prepared in this work. By using ex situ XRD, FT-IR, Raman measurements, the positive material and electrolyte material were characterized and analyzed.2. A lithium-iodine battery was prepared with two layers-lithium (negative material) and I2-LiI (HPN)2(positive material). The electrochemistry performance of the lithium-iodine battery was tested through constant resistance discharge.A new model of lithium-iodine battery (Li/I2-LiI(HPN)2) was developed. Its open voltage is 2.78V, the inner resistance is about 6.0kΩ/cm2. In the battery, LiI(HPN)2 play two functions:(1) providing I-, I- and I2 compose I3- and I5- ion, that is the active components, (2) a skeleton was formed by chemical bonds between lithium ion in LiI(HPN)2 and other cations, iodine anion is filled in the skeleton orderly. The channels in the 3d skeleton can be used to the transaction of iodine anion efficiently. During the discharge process, in the negative pole, lithium atoms lost electrons and become lithium cations, simultaneously, in the positive pole, Ix- get electrons and become I- anions. Then, the film of LiI layer generates. Accompanying the electrochemical reaction in the battery, LiI layer with low ion conduct property becomes thick, and that is the cause of the inner resistance increase in the battery.By the study on physical and chemical property of the positive material, new progress was made in lithium-iodine battery, and the electrochemical theory was preliminarily explained. The classical lithium-iodine battery with 2-ethenylpyridine as organic addictive, is mainly used as the power source for cardiac pacemaker applications. Its working life is 10～15 years. Because of complex manufacture process, its price is very high. If the classical primary lithium-iodine batteries can be made by adding new additive, there may be a sharp drop of operation risk and medical costs, their working life may be longer and their application field may be wider.
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