Low temperature performance of sodium-nickel chloride batteries with NaSICON solid electrolyte

A new type of sodium-nickel chloride batteries using NaSICON solid electrolytes (Na1 + xZr2SiR3 - xO12) was successfully investigated at much lower operation temperature of 195 degrees C compared with that of conventional Zebra batteries adapting same electrochemistry. The gradual phase transition in NaSICON from monoclinic to rhombohedral was perceived at 100-180 degrees C by high temperature XRD investigation. From symmetrical Na/NaSICON/Na cell test, the abrupt increase of cell resistance was observed at 177-180 degrees C, which reveals the change of ionic conduction mechanism in NaSICON solid electrolytes due to phase transformation. The sintered NaSICON solid electrolytes exhibit full densified morphology but somewhat lower average flexural strength of similar to 98 MPa compared with that reported for the (beta ''-Alumina solid electrolytes commercially available. The low temperature electrochemical performances of sodium-nickel chloride batteries were compared by using NaSICON and beta ''-Alumina solid electrolytes at 195 degrees C. The lower internal resistances of the cell using NaSICON were confirmed by impedance spectroscopy and cyclic voltammetry tests. Also proto-type cell tests revealed the clear advantages of NaSICON cell (N-Cell) over beta ''-Alumina cell (beta-Cell) at low temperature performances below 200 degrees C due to high Na+ ionic conductivity. (C) 2015 Elsevier B.V. All rights reserved.