(Battery Division Technology Award Address) A Path Toward Sustainable Battery Technologies

Abstract

Lithium-ion batteries have aided the revolution in portable electronics and are on the verge of transforming the transportation sector. They are also being intensively pursued for grid storage of electricity produced from renewable sources like solar and wind energies. While energy density and cycle life are critical, the battery developments will be increasingly driven by cost and sustainability considerations. This presentation will aim to layout a path forward toward progressively sustainable battery chemistries and technologies at an affordable cost.As this is a Battery Division Technology Award presentation, it will start briefly with the beginning of my career in batteries in the 1980s on a series of iron-based cathodes and their subsequent impact in battery technology developments. Then, the presentation will center on more recent work toward achieving progressively sustainable battery chemistries. First, the presentation will focus on reducing and eliminating cobalt in layered oxide cathodes by increasing the nickel content. Particularly, the challenges associated with bulk and surface instability as well as the importance of electrolytes to make the ultrahigh-nickel cathodes viable with high capacity and long life will be pointed out. Specific attention will be focused towards the challenges of scale-up and air stability of high-nickel cathodes. Second, eliminating lithium in oxide cathodes with sodium and the challenges associated even to a greater extent in sodium-based oxide cathodes with phase transitions and surface reactivity with electrolyte and ambient air will be discussed. Third, the replacement of transition-metal-based cathodes by metal-free sulfur cathodes in lithium-sulfur batteries will be presented. Particularly, the importance of evaluating in pouch cell configurations with practically necessary parameters like acceptable sulfur loading and low electrolyte/sulfur ratio along with stabilizing lithium deposition will be discussed. Finally, elimination of both lithium and transition-metal-based cathodes with sodium-sulfur batteries will be presented. Sodium-sulfur battery is a “dream technology” as both sodium and sulfur are earth-abundant, low-cost, and environmentally benign. With all the above four technologies, the importance of advanced characterization methodologies to understand the degradation mechanisms in-depth and strategies to overcome the challenges will be pointed out.