Open AccessTHE PHASE DIAGRAMS OF THE PSEUDO-BINARY SYSTEMS Li2SO4-Li2B2O4 Li2SO4-(NH4)2SO4 AND IONIC CONDUCTION INVESTIGATION
Author(s) -
车广灿,
陈立泉
Publication year - 1981
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.30.1219
Subject(s) - eutectic system , ionic conductivity , activation energy , materials science , ionic bonding , phase (matter) , amorphous solid , crystal (programming language) , phase diagram , analytical chemistry (journal) , lithium sulfate , thermal conduction , thermodynamics , ion , crystallography , chemistry , microstructure , chromatography , physics , organic chemistry , electrode , computer science , electrolyte , programming language , metallurgy , composite material
The pseudo-binary systems Li2SO4-Li2B2O4, Li2SO4-(NH4)2SO4 have been studied by means of DTA and X-ray diffraction techniques. Li2SO4-Li2B2O4 is a eutectic system. The eutectic reaction occures at 720℃ and 75 mol% Li2SO4. In Li2SO4-(NH4)2SO4 system there exists only one compound NH4LiSO4 which has a solid-solid phase transition at 186℃.The ionic conduction in both crystalline, amorphous Li2B2O4 and some samples with different compositions in Li2SO4-(NH4)2SO4 system have been investigated. It was found that below 400℃ the conductivity of amorphous Li2B2O4 is at least more than two orders of magnitude higher than that of crystalline sample and the activation energy of conduction is much smaller. The activation energy of LiNH4SO4 high temperature phase is only 0.12 eV while it's room temperature phase has a value of 0.70 eV. The ionic conductivity of the sample containing Li2SO4 40 mol% (LiNH4SO4 + [NH4]2SO4 two phase mixture) of the high temperature phase is about two orders of magnitude higher than that of pure LiNH4SO4. This suggests that when one kind of ionic crystal is added as a second phase into another ionic crystal, the ionic conductivity ofthe later could be increased remarkbly.