DESIGN,PREPARATION,PROPERTIES AND MANIFESTATION OF FUNCTIONALITY OF FLUORIDE-GRAPHITE INTERCALATION COMPOUNDS.

1.金属氟化物在AHF溶液中的插层机理：四氟化锡与石墨在有氟存在的液体AHF中反应，生成一个I_C= 11.53A的第二级石墨层间化合物，而无氟时不发生插层反应。然而，使用四氟化铅，反应在没有氟的情况下进行，产生阶段2化合物。结果表明，该体系中的反应是在无氟存在下进行的，其反应机理为：xC+PbF_4+ 2 HF *Cx（HF_2）_2+PbF_2PbF_4+ 4 HF <double half arrows>PbF_6^<2->+2H_2F_2 ^+Cx（HF_2）_2+PbF_6^<2-><double half arrows>CxPbF_6+2HF_2^-在该体系中，部分PbF_4起氧化剂的作用，形成GIC。F成键表明石墨层中的氟离子具有一定的迁移性，CxF是氟离子导电的固态电解质.氟嵌入反应和C-F键的性质：在液体HF中用元素氟较长时间（约8小时）氧化石墨通常得到具有半离子C-F键的富氟CxF（x&lt;4），而在室温下元素氟与石墨的直接相互作用产生具有离子C-F键的CxF（6&lt;x）。CxF的电化学特性半离子型CxF锂离子电池阴极的放电反应为非均相反应，而离子型CxF阴极的放电反应为均相反应。这种差异导致半离子CxF阴极的放电性能极其上级离子CxF阴极。

1.The Intercalation Mechanism in AHF solution of Metal Fluorides.The reaction of tin tetrafluoride with graphite in liquid AHF in the presence of fluorine yields a stage-2 graphite intercalation compound with an identity period I_C=11.53 A,whereas no intercalation reaction occurs without fluorine. With lead tetrafluoride, however, the reaction proceeds without fluorine yielding a stage-2 compound. From the results, it is concluded that reaction in this system proceeds in the absence of fluorine and the following reaction mechanism can be proposed :xC+PbF_4+2HF*Cx (HF_2) _2+PbF_2PbF_4+4HF <double half arrows> PbF_6^<2->+2H_2F^+Cx (HF_2) _2+PbF_6^<2-> <double half arrows> CxPbF_6+2HF_2^-In this system part of PbF_4 acts as an oxidizing agent for the formation of a GIC.2.Fluoride Ion Conduction of Fluorine Intercalated CxF.Impedance analysis of CxF with ionic or semi-ionic C-F bonding has indicated that the fluoride ions in the graphite gallery have some mobility, and that CxF are fluoride ion conducting solid state electrolytes.3. Fluorine Intercalation Reaction and the Nature of C-F Bonding.The longer time (ca.8 hours) oxidation of graphite by elemental fluorine in liquid HF usually give fluorine rich CxF (x<4) with semi-ionic C-F bond, whereas direct interaction of elemental fluorine with graphite at room temperature yields CxF (6<x) with ionic C-F bond. It has become possible to control the chemical composition, physical properties and C-F bond character by controling the intercalation reaction.4.Electrochemical Characteristics of CxF.The discharge reaction of semi-ionic CxF cathode for a lithium cell is a heterogeneous electrodereaction, While that of ionic CxF Cathode is a homogeneous reaction. This difference leads to discharge performances of semi-ionic CxF cathode which is extremely superior to those of ionic CxF.