Method for maintaining the performance level of an electrochemical cell

摘要

A method of maintaining the performance level of an electrochemical cell is described. The cell usually includes a negative electrode that includes an alkali metal; a positive electrode that includes at least one transition metal halide; a molten salt electrolyte based on an alkali metal haloaluminate; and a sodium ion-conducting solid electrolyte partitioning the positive electrode from the negative electrode. The method is based on a treatment regimen that includes the step of applying a series of electrical cycles to the cell, wherein the series includes at least one deep discharge of the cell. Each discharge of the cell is usually followed by recharging the cell to its available capacity.

主权项

1. A method of maintaining a performance level of an electrochemical cell having a negative electrode that comprises an alkali metal; a positive electrode that comprises at least one transition metal halide; a molten salt electrolyte comprising an alkali metal haloaluminate; and a sodium ion-conducting solid electrolyte that partitions the positive electrode from the negative electrode,
wherein said method includes a treatment regimen comprising the step of applying a series of electrical cycles to the cell, including at least one deep discharge of at least about 80% of the cell's available capacity, followed by recharging the cell; and then followed by at least two medium discharges, wherein each medium discharge is independently in the range of about 15% to about 45% of the cell's available capacity; and wherein each medium discharge is followed by recharging the cell; wherein the treatment regimen is carried out after the cell has been maintained for a period of time under a float condition associated with a charging voltage; and wherein the cell is returned to a float condition after the treatment regimen is completed; and wherein the “available capacity” of the cell is defined as the capacity discharged at a rate which would discharge the nominal, rated capacity of the cell to 1.8 volts (V) per cell, in 10 hours.