ChemInform Abstract: Development of a Ni,NiCl2 Positive Electrode for a Liquid Sodium (ZEBRA) Battery Cell.

Abstract

ChemInform Abstract A medium-temp. liquid sodium (ZEBRA) cell with a porous Ni,NiCl2 cathode that operates in a NaAlCl4 molten salt electrolyte is described and its electrochemical performance is studied in detail. Additions of sulfur to the NaAlCl4 electrolyte results in the development of a modified, high surface area, active metallic phase which is stable on charge/discharge cycling for many hundreds of cycles. The cells exhibit a high degree of reversibility and long cell life (> 2000 cycles) and operate in the temp. range 200-350 rc C. The cell has an open-circuit voltage of 2.58 V at 300 rc C and is an attractive candidate for use in high-energy and power density advanced batteries.

Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives

“…The third problem is capacity loss during cycling. Bones et al [5] studied stability of cell with nickel chloride cathode and observed capacity decreased by ∼50% in less than 10 cycles. The loss was diagnosed to be related to growth of nickel grains within the cathode during cycling.…”

“…Thus, mass transport of the species to BASE surface and potential ion exchange with sodium in the electrolyte could be prevented. So far, among various transition metal chlorides, nickel [4,5] and ferrous [77,78] chlorides meet the requirement and have been extensively studied. As seen in Eqs.…”

“…The open-circuit voltage of the cell is 2.59 V at 250 • C, which is 0.24 V higher compared to that of ferrous chloride cathodes. A number of studies have been carried out to understand the charge/discharge processes and improve the performance of nickel chloride cathodes [5,[79][80][81][82][83][84][85][86]. A low-conducting layer of nickel chloride was reported to form on the nickel surface during charge.…”

“…Considering that both anhydrous nickel chloride and metallic sodium are rather difficult to handle, the cell is typically assembled in the discharged state. A mixture of metallic nickel and sodium chloride powders is filled into the cathode chamber and sodium as well as nickel chloride are generated during the first charge [4,5].…”

Organic Electrolytes for Sodium Batteries

“…The cells were discharged with varying current densities (0.25, 0.5, 1.25, 2.5 and finally again 0.5 mA/cm 2 cathodic) until the presumable Na/Al plateau at 1.6 V (ref. 28,29,30) After the second discharge the OCV was around 2.4 V for both cells, indicating that Al has not been plated, and that the discharge unintended was stopped at the Na/FeCl 2 plateau. We observed a big voltage drop when going from the FeCl 3 to the FeCI 2 plateau as expected (Wilkes et al in reference 84).…”