Voltage increase of copper compound electrodes resulting from the addition of sulphur for seawater batteries

S as additive in Mg–Cu2O seawater batteries using Ni foam-supported electrode

“…Renuka [9] put one hypothesis in the voltageincreasing effect of sulphur in copper compound batteries, that is, during discharge sulphur probably reacts with the highly active copper formed when the prime depolariser is reduced, producing copper sulphide, thus accounting for the fact that no copper is observed at the end of discharge. Some investigations also indicate that copper compounds (either soluble, sparingly soluble, copper (I), or copper (II) compounds) increase their potentials when elemental sulphur is added [8][9][10][11]. Hiroi [11], based on his studies of the Mg-CuI system, proposed that the electrode reaction, viz, CuI þ e ¼ Cu þ I; changes in the presence of sulphur to 2CuI þ S þ 2e À ¼ Cu 2 S þ 2I À and hence causes the elevation in cell voltage.…”

“…Some investigations also indicate that copper compounds (either soluble, sparingly soluble, copper (I), or copper (II) compounds) increase their potentials when elemental sulphur is added [8][9][10][11]. Hiroi [11], based on his studies of the Mg-CuI system, proposed that the electrode reaction, viz, CuI þ e ¼ Cu þ I; changes in the presence of sulphur to 2CuI þ S þ 2e À ¼ Cu 2 S þ 2I À and hence causes the elevation in cell voltage.…”