Metal phthalocyanine-catalysed Li/SOCl2 cells

The discharge capacity and voltage of Li/SOCl2 cells were investigated as a function of doping the carbon cathode with transition and non-transition metal phthalocyanines (M-Pcs). The nature of the metal atom and the sintering temperature of the carbon/metal complex mixture were identified as the two important factors affecting catalytic activity. M-Pcs which M is a transition metal such as Co, Ni, V, Cu and Mn are catalytically active while non-transition metals such as Li, Zn and Mg are inactive. Analytical data obtained with Co-Pc could be modelled in terms of the following processes during sintering of a carbon/M-Pc mixture. A "strongly adsorbed M-Pc/carbon catalyst" is first formed during sintering at about 600°C. This catalyst improves both the capacity and voltage of the Li/SOCl2 cell. Increasing the sintering temperature to 800°C appears to cause the decomposition of the metal macrocycle accompanied by chemical bonding of the metal to the carbon through an oxygen or a nitrogen. This catalyt primarily increases the voltages of the cell with only minor improvement of cell capacity.