With fast deployment of wind and solar energies, battery research and development have devoted great attentions to arise advanced energy storage technologies with low cost, high energy density, long-term stability, and safety. Among various energy storage systems (ESS) that have been explored, intermediate temperature sodium-metal halide (IT Na-MH) batteries are considered as one of the most promising rechargeable battery candidates for stationary applications due to their appreciable advantages such as low cost of raw materials, long cycle life, and safety, etc. One of the challenges for further lowering the operating temperature of Na-MH batteries is to overcome the interfacial resistance between sodium and b″-alumina solid-state electrolyte (BASE). In present work, we demonstrate that pre-deposition of a buffer on the surface of BASE could significantly affect the sodium wettability. The detailed spectroscopic characterizations for the buffer layers indicate a strong correlation between the different thermal treatments, the evolution of the particle morphology, and sodium wetting. Indeed, IT Na-MH batteries with pre-deposited buffer layers on the anode side present much stable battery performances and long-term cycleability. Therefore, the results from this work will further advance IT Na-MH battery technologies for the practical application in future ESS markets.
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