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

1.金属氟在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，生成第二阶段的石墨层间化合物，等周期I_C=11.53A，而无氟时不发生插层反应。然而，对于四氟化铅，反应在没有氟的情况下进行，生成第二阶段的化合物。结果表明，该体系的反应在无氟条件下进行，反应机理为：XC+PbF_4+2Hf*Cx(Hf_2)_2+PbF_2PbF_4+4Hf&lt；双半箭&gt；PbF_6^&lt；2-&gt；+2H_2F^+Cx(HF_2)_2+PbF_6^&lt；CxPbF_6+2Hf_2^-在该体系中，部分PbF_4作为氧化剂形成GIC。2.氟插层CxF的氟离子导电性。CxF与离子或半离子C-F键的阻抗分析表明，CxF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液。氟插层反应及C-F键性质在液态HF中，元素氟较长时间(约8小时)氧化石墨，通常生成富氟CxF(x&lt；4)，具有半离子C-F键，而元素氟与石墨在室温下直接作用，生成具有离子C-F键的CxF(6&lt；x)。通过控制插层反应可以控制CxF的化学组成、物理性质和C-F键性质。4.CxF的电化学特性半离子CxF正极对锂电池的放电反应是非均相电化学反应，而离子CxF正极的放电反应是均相反应。这种差异导致了半离子CxF阴极的放电性能远远优于离子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.