Lithium oxide thermal conductivity

Synthesis of comb (regular graft) copolymers having a PDMS backbone and polyethylene oxide) teeth was reported 344). These copolymers were obtained by the reaction of poly(hydrogen,methyl)siloxane and monohydroxy-terminated polyethylene oxide) in benzene or toluene solution using triethylamine as catalyst. All the polymers obtained were reported to be liquids at room temperature. The copolymers were then thermally crosslinked at 150 °C. Conductivities of the lithium salts of the copolymers and the networks were determined. 

Preliminary electrochemical tests of materials obtained have been performed in two types of cells. Primary discharge measurements have been executed in standard 2325 coin-type cells (23 mm diameter and 2.5 mm height) with an electrolyte based on propylene carbonate - dimethoxyethane solution of LiC104. Cathode materials have been prepared from thermally treated amorphous manganese oxide in question (0.70 0.02g, 85wt%.) mixed with a conductive additive (10 % wt.) and a binder (5wt%). Lithium anodes of 0.45 mm thickness have been of slightly excess mass if compared to the stoichiometric amount, so as to ensure maximal possible capacity of a cell and full consumption of the cathode material. 

Thermal and Conducting Properties of Polymer-LiC104 Mixtures. Plots of the conductivity, a, of homogeneous, transparent mixtures of LiCl04 PMMS-8 and PAGS-12 exhibit distinct maxima at ratios of ethylene oxide units to lithium (EO/Li of 20-25 (Figure 2). This behavior is typical for amorphous polymer electrolyte complexes (7, 8). An increase... 

Kim, D.W., Park, J.K., and Rhee. H.W. 1996. Conductivity and thermal studies of solid polymer electrolytes prepared by blending poly(ethylene oxide), poly(oligo[oxyethylene] oxysebacoyl) and lithium perchlorate. Solid State Ionics 83, 49-56. 

Pitawala et al., (2007) studied the combined effect of both plasticizer and nano-ceramic filler on the thermal behavior and conductivity of (PEO)g-lithium trifiuoromethanesulphonate (LiCFjSOj or LiTf) composite polymer electrolyte. The formula (PE0)gLiCFjS03 denotes the chemical composition of the polymer-salt complex in which 9 is the molar ratio of (ethylene oxide (EOl/LiCF SOj). According to their work, addition of 15 wt% Aip lowered the and T of (PEO)gLiTf from 58 °C and °Cto 51 °C and -50 °C, respectively and the con-... 

The nonstoichiometry of an oxide strongly depends on the presence of alio-valent impurities and dopants affect the number of thermal defects in non-stoichiometric oxides and their electrical conductivity because the solutes have a valence other than the atoms they replace. This is illustrated in the case of lithium and chromium doping of nickel and zinc oxides in equilibrium with gaseous oxygen. 

An ideal electrolyte solute in lithium-ion cells completely dissolves and dissociate, in the nonaqueous media, and the solvated ions should be able to move in the media with high mobility, should be stable against oxidative decomposition at the positive electrode, should be inert to electrolyte solvents and other cell components, and should be nontoxic and remain stable against thermally induced reactions with electrolyte solvents and other cell components. LiPF6 is one of the most commonly used salts on commercial Li-ion cells. The success of LiPF6 was not achieved by any single outstanding property but, rather, by the combination of well-balanced properties, namely, conductivity, ionic mobility, dissociation constant, thermal stability, and electrochemical/chemical stability. 

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