Discharge behaviour of copper(II) halide cathodes with molten nitrate electrolytes

Abstract

This paper describes the discharge behaviour between 150 and 220°C of cells using copper(II) halide as the cathode material and molten nitrate as the electrolyte for a reserve battery of high energy density running at medium temperatures. At these temperatures a lithium–aluminium alloy/copper(II) chloride cell can be discharged at a current density of 50mAcm−2. The open-circuit potentials are 3.45V (against 20wt% lithium–aluminium alloy). Discharge results on the combination LiAl/LiNO3–KNO3/CuCl2 cells show a capacity of 1343Cg−1 to zero voltage at a current density of 50mAcm−2 at 230°C. In practice, this is equivalent to a specific energy output of 356Whkg−1 of cathode to a 70% voltage cut-off. The compatibility of copper(II) chloride with nitrate electrolytes has been investigated. Copper(II) chloride appears to be compatible with nitrate up to about 260°C. The performance of the LiAl/NO3/CuF2 cell was very poor giving a capacity of 50Cg−1.