O.V. Volkova, V.V. Zakharov, E.A. Il’ina, A.A. Pankratov.
ABSTRACT
Discharge characteristics of the heat activated battery with NiCl2-CoCl2 mixtures as a cathode material has been investigated. Using of mixtures instead of individual nickel (II) chloride and cobalt (II) chloride allows to decrease of the discharge temperature of electrochemical cell was founded. The minimum temperature for fixing of a stable discharge plateau is 480°C. The maximum capacity of the discharge plateau is 0.33 A×h×g-1. The optimal composition of the cathode mixture contains 20 wt. % CoCl2. Composition and morphology of reduction products of the cathode materials have been determined. It was found that during the discharge of electrochemical cell, the initial nickel and cobalt chlorides are reduced to metals. The reduction process is accompanied by diffusion of lithium halides from the separator into the cathode space. Reduced metals (Ni, Co) form a network of branched dendrites covered with a salt film based on lithium chloride. The density and morphology of the dendritic sediment is determined by the composition of the initial cathode mixture. The salt film consists of solid solutions and peritectics of the system Li, Co, Ni½½Cl, Br, F. It was shown that the reduction process of Me2+-ions (where Me – Ni, Co) to the metal Me0 proceeds through the melt mechanism in the mode of diffusion kinetics.
KEY WORDS:
thermoactivated chemical current sources; cathode; cobalt chloride; nickel chloride
DOI: 10.31857/S0235010621020092