Lawrence Berkeley National Laboratory Lawrence Berkeley National Laboratory Title NOVEL GRAPHITE SALTS OF HIGH OXIDIZING POTENTIAL Permalink https://escholarship.org/uc/item/06c0z65s Author McCarron III, Eugene Michael Publication Date 1980-08-01 eScholarship.org Powered by the California Digital Library University of California , LBL-11272 "" __ c. (r- IT'll Lawrence Berkeley Laboratory 1&:1 UNIVERSITY OF CALIFORNIA RECEIVED Materials & Molecular LAWRENCE Research Division OCT 8 1980 Ll8RAI~Y /\ND DOCUMENTS SECTION NOVEL GRAPHITE SALTS OF HIGH OXIDIZING POTENTIAL Eugene Michael McCarron III (Ph.D. thesis) TWO-WEEK LOAN COpy August 1980 This is a Library Circulating Copy which may be borrowed for two wee~s. For a personal retention copy, call Tech. Info. Dioision, Ext. 6782 r-­ r­\fJ t 9.) -J r~ \"! Prepared for the U.S. Department of Energy under Contract W-7405-ENG-48 ,) r \ \ - LBL-11272 NOVEL GRAPHITE SALTS OF HIGH OXIDIZING POTENTIAL Eugene Michael McCarron III Materials and Molecular Research Division Lawrence Berkeley Laboratory and Department of Chemistry University of California Berkeley, California 94720 This work was supported by the U.S. Department of Energy under contract No. W-7405-ENG-48 For those special people: "I have a feeling we're not in Kansas any more." iii NOVEL GRAPHITE SALTS OF HIGH OXIDIZING POTENTIAL Table of Contents List of Tables. • vii List of Figures • • • • • • • •• l.X Acknowlegments ••••• xi Abstract • • • • • • xiii I. GENERAL INTRODUCTION • 1 II. GENERAL APPARATUS AND HANDLING TECHNIQUES ••• 3 A. Apparatus ••••••••••••••• 3 1 . Gene r a 1 • • • . 0 • • 0 • • • • • • • 3 2. In-Situ Sample Shroud for X-Ray Diffractometer Studies . 0 • • • 0 • • • • 0 • 4 3. Battery Casing for Solid Electrolyte Cells • • 5 4. Teflon FEP-Quartz Capillary Seals. 5 B. Reagents • 6 1- Graphite • 6 2. Metals • 7 3. Metal Hexafluorides •• 7 4. Rhenium Heptafluoride. • 8 5. Dioxygenyl Hexafluorometallate Salts 8 6. Gases and Volatile Liquids • • 8 C. Instrumentation. • • • • • 9 1. X-Ray Powder Diffraction ••• 9 2. X-Ray Powder Photography. 10 3. Single Crystal Precession Photography 10 4. Magnetic Susceptibility. 10 5. Infrared Spectroscopy •• 11 6. Raman Spectroscopy •••• 11 7. Chemical Analysis ••••• 11 8. Electrical Conductivity Measurement ••• 12 9. t/to Measurement ••••••••••• 13 10. Electrochemical Potential Measurement •• 13 References. 14 Figures • • 15 III. REACTIONS OF THE PLATINUM METAL HEXAFLUORIDES 22 A. Introduction. 22 B. Experimental 23 1. Graphite/Tungsten Hexafluoride. 23 2. Graphite/Rhenium Hexafluoride. 23 iv Table of Contents (continued) 3. Graphite/Osmium Hexafluoride •• 24 4. Graphite/Iridium Hexafluoride. • 24 5. Graphite/Platinum Hexafluoride • 25 6. Hydrolysis of G/MF6 Salts •••• 25 7. G/IrF6 Reduction with Hydrogen • 26 C. Magnetic Studies on Graphite/MF6 • • 26 D. Structural Studies on Graphite/MF6 • 27 E. Results and Discussion 27 References. 31 Tables. 32 Figures • • 35 IV. DIOXYGENYL SALTS WITH GRAPHITE. 39 A. Introduction. 09 B. Experimental • 40 I. Graphite/02PtF6 •• 40 2. Graphite/02AsF6o 40 3. Graphite/02AuF6. 0 41 C. Results and Discussion • • • • .. • • e e '" 0 42 References. • 4S V. FLUORINE INDUCED INTERCALATION OF GRAPHITE BY BINARY METAL FLUORIDES. • • 0 • • • • • • • • 46 A. Introduction. 46 B. Experimental . · 0 · · · · · · · · . · 48 1. Graphite/WF6/F2· · · · · · · 48 2. Graphite/ReF6/F2 · · · · · · · · 0 · · . 48 3. Graphite/ReF7'; . · . · · · · · · 0 · 48 4 •. Graphite/PFS/F2. · · · · 49 5. Graphite/SiF4/F2 · · · · · · · · · · · . · 49 6. Graphite/SnF4/F2 . · · · · · · · · · 49 C. Results and Discussion 49 References ••••••••••• 53 v Table of Contents (continued) VI. COMPOSITION AND STAGING IN THE GRAPHITE/AsF6 SYSTEM AND ITS RELATIONSHIP TO GRAPHITE/AsF5. 54 A. Introduction 54 B. Experimental •••. 55 1. Graphi tel AsFs.. .• • • 55 2. Graphite/AsF6' • • ••. 56 3. Graphite/AsF6 + AsF3 •••••• 56 C. X-Ray Diffraction Studies. • •••• 58 1. HOPG Diffraction Studies •••• 58 2. Single-Crystal Precession Photography Data for C8AsF6 at Room Temperature 58 D. Results and Discussion 59 References. • 64 Tables. 66 Figures ° • • 75 VII. FLUOROGERMANIUM (IV) SALTS OF GRAPHITE--A SYSTEM IN EQUILIBRIUM WITH ELEMENTAL FLUORINE . •.• • • 82 A. Introduction • • 82 B. Experimental • 83 1. Graphite/GeF4o 83 2. Graphite/GeF4/F2. 83 i) Low Pressure F2 •••••• 83 ii) Higher Pressure F2 84 iii) X-Ray Diffraction Studies • 85 3. C12GeF5 + GeF4 0 • 86 4. CI2GeFs·l/2 GeF4 + F2 86 5. C12GeF5 + SiF4 • • • . • • • • • 87 6. C12GeFs + SF6 0.... 87 C. Results and Discussion. 87 References. 92 Tables. 94 Figures • • • . 97 vi Table of Contents (continued) VIII. ELECTRICAL CONDUCTIVITIES OF NOVEL GRAPHITE SALTS. • 100 A., Introduction • 100 B. Experimental. • 102 1. General Conductivity Measurement 102 i) Sample Preparation • • • • • • • 102 ii) Electrical Conductivity Measurement. •• ••• 103 2. Graphite/MF6 (M = Os, Ir) Conductivities 103 3. Graphite/PtF6 Conductivities • • • • • • • 104 4. Graphite/AsF6 versus Graphite/AsFs Conductivities ••• 105 C. Results and Discussion • . • 106 References •• • • • • • 110 Tables •• • • • 112 Figures • • • • 114 IX. A POSSIBLE ELECTRICAL-ENERGY-STORAGE BATTERY UTILIZING GRAPHITE SALTS •••• • • • • • • • 118 A. Introduction 118 B. Fluoride-Ion Conductors •• • 118 C. Solid. Galvanic Cells •• • 119 1. Experimental. 119 2. Results • 119 3. Discussion • • 121 D. Conclusion and Prospects for Future Work. • 122 References • • • • • 123 Tables •••• • 124 Figures • • 126 APPENDIX • 127 vii List of Tables III-I. Specific conductivity of some graphite salts. • • • • • 32 111-2. Third-transition-series hexafluorides: the non-bonding electron configurations, molecular volumes and electron affinities • • • • • • • • • • • • • • • • • 33 111-3. Maximum intercalation of HOPG by metal hexafluorides. • 34 VI-I. Evidence for the composition-staging formula, C8nAsFS (n being the stage), in the system graphite/AsFS 66 VI-2. Removal of As-containing species from graphite/AsFS • 67 VI-3. Fluorine uptake by graphite/AsFs: arsenic-rich systems. • 68 VI -6. Fluorine uptake as a function of time by graphite/AsFS: arsenic-poor systems. • • • • • • • • • • • • • ••• 69 VI-So Evidence for the composition staging formual, C12nAsF6 (n being the stage), in the system, graphite/AsF6 •• 70 VI-6. Removal of As-containing species from graphite/AsF6 • 71 VI-7. Generation of graphite/AsFS materials by the addition of AsF3 to graphite/AsF6 salts •••••••••••• 72 VI-8. Typical fluorination-titration cycle for graphite/AsFS_6 •• 73 VI-9. Evidence for the composition-staging formula, C12nMF6 (n being the stage), in graphite/MF6 systems. • ••• 74 VII-I. Stoichiometry of graphite salts intercalated with a GeF4/F2 - excess mixture at low pressure (total pressure < 1 atmosphere) ••••• 94 VII-2. Stoichiomery of graphite salts intercalated with a GeF4/F2 - excess mixture at higher pressures (total pressures ~ 2 atmospheres) • • • • •• 9S VII-3. Uptake of neutral molecules, MFx , by C12GeFS to form C12GeFs·oMFx • • • • • • • • • • •.. 96 VIII-I. Composition and electrical conductivity data for HOPG/MF6 and HOPG/AsFS/F2 intercalates •••••• 0 ••••••• 112 viii List of Tables {continued VIII-2. Effect on the per plane conductivity, k, with the removal/ addition of arsenic-containing species from graphite/ AsF5-6 materials. • • • • • 0 0 • • •• • •••••• 113 IX-I. Conductivities of some solid electrolytes at 200 and 1500 C and their activation energies • • 124 IX--2. Galvanic cells studied •• • 125 IX-3. Galvanic cells previously reported. • 125 ix List of Figures II-I. In-situ sample shroud for x-ray diffractometer studies. IS II-2. Battery casing for solid electrolyte cells. 16 II-3. Teflon FEP - Quartz capillary seals. • . • • 17 II-4. Inert-atmosphere HOPG intercalate sample holder for powder diffractometer • • • •• •• • • • • • • • •• 18 II-S. In-situ reaction apparatus for single crystals of graphi te. 0 • • 0 • • • • • 0.. II 0 • 19 II-6. Apparatus for in-situ measurement of conductivity on HOPG/intercalates. • . •• • •••••• 20 II-7. Contactless inductive technique for measurement of conductivity •••• 21 III-I. Magnetic susceptibility-temperature relationships for C8+0sF6- and SF3+0sF6-. • . • • . • • • . • • 3S 111-2. Magnetic susceptibility-temperature relationships for C8+1rF6- and H30+IrF6-. • • . • • • • • . • • • 36 111-3. Diffraction tracings of (a) C80sF6 and (b) C8IrF6 37 III-4. Proposed structures for (a) C8X and (b) ,C12X. 38 VI-I. Arsenic K-shell pre-absorption edge spectra. • 7S VI-2. Infrared spectra of volatiles removed from C8AsFS as a function of pumping time. • • • • • • . 76 VI-3. Composition/staging relationships for CxAsFS and CxAsF6 77 VI-4. Generalized reaction scheme for arsenic-rich (mole ratio C/As = x <24) graphite/AsFS systems ••.•••••.. 78 VI-So Generalized reaction scheme for arsenic-poor (mole ratio C/ As = x > 48) graphi tel AsFS sys terns • • • . 79 VI-6. Generalized reaction scheme for graphite/AsFS systems with a mole ratio C/As = 24 < x < 48 •••.••. , . 80 VI-7, Structural models for (a) Cl2AsF6 or CI2AsF6'1/2 AsF3 and (b) C8AsF6 • . • . • • • • . • • . • 81 x List of Figures (continued) VII-I. X-ray diffraction tracings of CIsGeFS-6 as a function of fluorine content • • • • • • • • • • • • • • • • 97 VII-2. Proposed ordered structure for CI2GeF6' 98 VII-3. Proposed ordered structure for CI2GeFS.S ,[C243+(GeF6=)(GeFs-)] •••••••• 99 VIII-I. Plots of specific conductivity, a, versus stage, n, for CSnAsFS·· . · l1l~ VIII-2. Plots of the conductivity per graphite plane, k, versus