Research Area

With the invention of non-aqueous electrolytes which enabled the use of alkali metal anodes, the energy density of batteries exhibited a remarkable improvement. However, in order to mitigate the safety issues the energy density was compromised and Li ion batteries (LIBs) were designed and got wide popularity especially in the potable electronic market. Fast approaching saturation curves of LIB performance matrices and pressing demands for higher energy and power density energy storage systems to support high energy demanding applications viz. electric vehicles make a situation inevitable to stretch out beyond LIBs. Revisiting Li metal anodes as in Li-O₂ non-aqueous chemistry seems to be promising even though the understanding of the mechanism is in its infancy. Major bottle neck of exploiting the reversible reaction between Li⁺ and O₂ is the sluggish kinetics of the electrochemical decomposition of the discharge product viz. Li₂O₂ to Li⁺ and O₂ (Oxygen Evolution Reaction-OER). Fundamental understanding of Li-O₂ electrochemistry is believed to pave way for other alkali Metal-Air batteries.

Various approaches aiming to improve the kinetic requirements of the fast charge/discharge include, addition of redox mediators, solubilizing agents etc. Carbonaceous matrices have been nanoengineered to facilitate the discharge process (Oxygen Reduction Reaction-ORR) and mass transport, thus currently playing pivotal role beyond just as catalyst support layer. Our recent oxyhalogen-sulfur electrochemistry approach synergistically combines these two and the round-trip efficiency is remarkably improved. Multi-faceted approaches to take control over the nucleation site, size and composition of the discharge products is critical in the design and fabrication of a practically usable Metal-Air battery.

  Schematic depicting the mechanism of oxyhalogen-sulfur electrochemistry driven charge discharge processes

Highlighted Publications:

X. Wang, Y. Li, X. Bi, L. Ma, T. Wu, M. Sina, S. Wang, M. Zhang, J. Alvarado, B. Lu, A. Banerjee, K. Amine, J. Lu, and Y. S. Meng “Hybrid Li-Ion and Li-O2 Battery Enabled by Oxyhalogen-Sulfur Electrochemistry“, Joule. 2018, 2, 11, 2381