Operating Temperature on Cathode Material and Electrochemical Performance of Na-NiCl2 Batteries

Na-NiCl 2 battery is an intermediate temperature battery of which the operating temperature is one of the crucial factors for its electrochemical performance and needs to be fully understand.The effects of operating temperature on electrochemical performance of Na-NiCl 2 batteries and morphology of the cathode material under different temperatures were studied based on the results of cell test, EIS and SEM measurements.It was found that the reduction of the operating temperature of the Na-NiCl 2 battery within a certain range suppressed the growth of nickel particles during cycling and improved the cycle performance of the cell with and without sulfur in the cathode.The surface activity of the nickel particles decreased with reduction of the operating temperature, while the growth rate of nickel particles slow down at low temperature, resulting in improved cell cycle performance of the cell improves.However, much lower operating temperature leads to poor electrochemical performance due to slow electrochemical reaction rate, migration rate of Na + and poor wettability of sodium on ceramic electrolyte.Based on above tests, the optimum operating temperatures of the cell no matter with or without sulfur are about 260℃.