DESIGN,PREPARATION,PROPERTIES AND MANIFESTATION OF FUNCTIONALITY OF FLUORIDE-GRAPHITE INTERCALATION COMPOUNDS.
Grant-in-Aid for General Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||SHINSHU UNIVERSITY|
TOUHARA Hidakazu SHINSHU UNIVERSITY,FAC.TEXTILE SCIENSE AND TECHNOLOGY,PROFESSOR, 繊維学部, 教授 (40026141)
OKINO Fujio SHINSHU UNIVERSITY,FAC.TEXTILE SCIENSE AND TECHNOLOGY,PROFESSOR LECTURER, 繊維学部, 講師 (60214037)
|Project Period (FY)
1993 – 1994
Completed(Fiscal Year 1994)
|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1994 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1993 : ¥1,400,000 (Direct Cost : ¥1,400,000)
|Keywords||Graphite Intercalation Compounds / Intercalation Reaction / Fluoride / Matal Fluoride / Lithium Battery / Fluoride Ion Conduction / 金属フッ化物 / 相転移|
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_2
PbF_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.
Research Products (5results)