IIT Delhi Researchers Tackle Dendrite Growth, Enhancing Sodium-Sulfur Battery Performance

Researchers at IIT Delhi's DESE have stabilised room-temperature sodium-sulfur batteries by using an iodide-based additive in the electrolyte to address dendrite-related issues. Check details here

Researchers at the Department of Energy Science and Engineering (DESE) at IIT Delhi have made significant strides in stabilizing room-temperature sodium-sulfur battery technology. They have achieved this breakthrough by incorporating an iodide-based additive into the organic electrolyte solution, addressing the dendrite-related challenges associated with the technology.

“This exciting development highlights the importance of innovative research in addressing global energy challenges. By harnessing the power of abundant and safe materials like sodium and sulfur and enhancing their performance with innovative additives like BiI3, we move closer to a future where sustainable energy storage is accessible to all. Room-temperature sodium-sulfur batteries would be ideal for use in electric vehicles and grid applications,” said Prof. Vipin Kumar from the Department of Energy Science and Engineering, IIT Delhi.

Dendrites are branched structures that naturally form on most metal anodes. Their growth is driven by two main factors: first, the continuous reaction between the electrolyte and the sodium metal anode creates a highly irregular local surface. Second, the solid electrolyte interphase a thin, electrically insulating but ionically conductive layer is both mechanically and chemically unstable.

The scarcity of electrode materials and the supply chain of other critical components has challenged the sustainability of lithium-ion batteries, prompting battery manufacturers to look for alternative battery technology. The room-temperature sodium-sulfur (RT-Na/S) batteries, which comprise abundant and inexpensive electrode materials in the form of sodium and sulfur and rely on a different kind of chemical reaction, making them capable of storing much more energy in comparison to state-of-the-art lithium-ion batteries, may prove a potential alternative.

However, one of the main problems with RT-Na/S batteries has been dendrite growth on the sodium metal anode, causing the cell to fail prematurely. Prof. Vipin Kumar and research scholar Chhail Bihari employed Bismuth iodide (BiI3) as an additive molecule to alter the properties of the electrolyte. BiI3 reduces the energy required for sodium ions to leave the solvent and enter the electrode, improving the charge transfer kinetics. This results in better battery efficiency and faster charging times.

Moreover, the presence of BiI3 contributes to the formation of a Na3Bi alloy interphase and stable solid electrolyte interphase (SEI) on the sodium metal anode. This layer is crucial as it prevents the growth of sodium dendrites, which can cause short circuits and degrade the battery's performance over time,

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