Propylene carbonate capacity measurements

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. 

A few measurements have been reported for ethylene carbonate, propylene carbonate, 4-butyrolactone and 4-valerolactone. ° These compounds are aprotic 5-membered heterocylic ring structures with unusually large dipole moments. Dielectric constants range from 36 for valerolactone to 89.6 for ethylene carbonate. All appear to be normal polar liquids. In all four solvents a capacity hump is observed on the positive side of the pzc (Fig. 7.2.5). The temperature coefficient of capacity at the hump in the butyrolactone solution is only one third of its value in DMSO and sulpholane, and less than one tenth of the water value. Anions appear to be specifically adsorbed as in other solvents. Strong specific adsorption of CIO4 anions from propylene carbonate has been reported. Butyrolactone is strongly adsorbed from aqueous solutions. ... 

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