Feasibility Study of a Planar-type Sodium-Nickel Chloride Battery

The sodium–nickel chloride (Na/NiCl2 ) battery has many advantages over the Na–S battery, such as a higher operating voltage, ease of assembly in the discharge state, less corrosive cathode materials, a safer cell failure mode, and better tolerance against overcharging. In this study, to solve the problem of low electrical conductivity, a planar-type Na/NiCl2 cell was designed by optimizing the cathode through the use of both Ni mesh and excess Ni powder. A β″-Al2O3 membrane, which plays a role in the conducting path for Na+ ions, was glass-sealed and attached to a thicker external α″-Al2O3 ring. For carbon coating, the anode side of the membrane was covered with carbon paste. The prototype cell was operated successfully and showed excellent electrochemical characteristics in terms of high Na utilization and stable charge/discharge cycleability.