High temperature versus low temperature Zebra (Na/NiCl2) cell performance

• Published in: Journal of power sources 2012-05, Vol.206, p.402-408
• Main Authors: Hosseinifar, Mehdi, Petric, Anthony
• Format: Article
• Language: English
• Subjects: Applied sciences; Cycle life assessment; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Sodium/nickel chloride battery
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.01.125

► Rapid cycling of Zebra cells is examined at 260 and 350°C. ► The cells cycled at 260°C failed in discharge after 300 cycles. ► Significant capacity loss occurred in cells cycled at 350°C after 600 cycles. ► The failure at 260°C is linked to the formation of AlF3 phase on β″ electrolyte. ► At 350°C, growth of Ni particles is found to be the cause of capacity loss. The effect of operating temperature on performance and aging of Zebra cells was investigated. The cells were cycled at 260°C and 350°C using a modified charging regime to accelerate damage. The cathode and solid electrolyte of degraded cells at the end of cycling were analyzed by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. It is hypothesized that the formation of AlF3 on the surface of the β″ alumina electrolyte contributes to the failure of cells at low temperatures. A mechanism based on the overcharge reaction is proposed for the formation of this phase. At 350°C, a significant capacity loss was observed with cycle life, which correlates to nickel particle growth as the cause of this phenomenon. The factors responsible for Ni grain growth are discussed.