Large scale battery technologies have gained more attention as electric energy storage devices for renewable energy applications and grid stabilization. Due to growing safety concerns, high material costs and a limited cycle life, conventional lithium ion battery technologies have a limited portfolio for stationary applications. Recently, the sodium-nickel chloride (Na-NiCl₂) battery has been under consideration as an alternative battery technology for stationary energy applications.[1] Yet, there are a number of challenges, such as the high operating temperature and high cost of hermetic sealing technologies, that hinder a further market penetration.

Typically, a tubular type Na-NiCl₂ battery is operated at a high temperature above 280°C to obtain a reasonable electrochemical performance. Our recent work has demonstrated that a planar type Na-NiCl₂ battery can achieve remarkable electrochemical performance over 1000 cycles even at an intermediate temperature (IT) of 190°C.[2] The lower operating temperature allows for the development of cost-effective sealing technology that uses conventional high temperature polymers as sealing materials.[3] We also demonstrate the Ni content in the cathode can be greatly reduced by 30% compared to that of the conventional Na-NiCl₂ battery. Long term cell tests using the advanced cathode formula show a stable battery performance over 250 cycles.[4]

Therefore, our work suggests that developing polymer sealing technology and advanced low Ni-content cathode materials at intermediate operating temperatures might provide a new breakthrough to Na-NiCl₂ batteries for practical stationary energy storage applications.

REFERENCES

1. J. L. Sudworth, J. Power Sources, 51 (1994) 105-114.

2. G.S. Li, X.C. Lu, J.Y. Kim, K.D. Meinhardt, H.J. Chang, N.L. Canfield, V.L. Sprenkle, Nat. Commun., 7 (2016) 10683.

3. H. J. Chang, X. Lu, J. F. Bonnett, N. L. Canfield, S. Son, Y. Park, K. Jung, V. L. Sprenkle, and G. Li. (submitted)

4. H. J. Chang, X. Lu, K. Jung, V. L. Sprenkle, and G. Li. (in preparation)