Co‐Regulating Planar Mg Deposition and Bromine‐Rich Mg Anode‐Electrolyte Interface by Multifunctional Organic Bromine Additive

Co‐Regulating Planar Mg Deposition and Bromine‐Rich Mg Anode‐Electrolyte Interface by Multifunctional Organic Bromine Additive

Advanced Energy Materials

10.1002/aenm.202500979

https://doi.org/10.1002/aenm.202500979

Deviprasath Chinnadurai, Sonal Kumar, Chang Zhang, Man‐Fai Ng, Yuanjian Li, Jianbiao Wang, Tanmay Ghosh, Gaoliang Yang, Zhenxiang Xing, Wei Liu, Zhi Wei Seh

Br-rich SEI, high areal capacity cycling, magnesium batteries, organic bromine additive, planar Mg deposition

01 June 2025

Chinnadurai, D., Kumar, S., Zhang, C., Ng, M., Li, Y., Wang, J., Ghosh, T., Yang, G., Xing, Z., Liu, W., & Seh, Z. W. (2025). Co‐Regulating Planar Mg Deposition and Bromine‐Rich Mg Anode‐Electrolyte Interface by Multifunctional Organic Bromine Additive. Advanced Energy Materials, 15(32). Portico. https://doi.org/10.1002/aenm.202500979

Rechargeable magnesium batteries (RMBs) are highly promising candidates for next‐generation energy storage systems due to their superior energy density and intrinsic safety. However, severe magnesium (Mg) anode passivation in conventional electrolytes and non‐uniform Mg deposition significantly compromise their reversibility and cycling stability. Here, for the first time, a multifunctional 1‐bromooctane (OctylBr) additive is introduced into the strongly passivating magnesium bis(hexamethyldisilazide) (Mg(HMDS)₂) electrolyte to engineer a Br‐enriched solid electrolyte interphase (SEI) and promote uniform planar Mg deposition. This strategic electrolyte modification extends the Mg cycling lifespan of conventional electrolytes from 0 to 3600 h with an exceptionally low overpotential of 45 mV in a symmetric cell and a high coulombic efficiency of 99.34% in an asymmetric cell. The planar deposition enabled by the electrolyte allows for reversible Mg plating/stripping across a broad range of areal capacities (0.5–25 mAh cm−2). Notably, at high areal capacity of 10 mAh cm−2, the electrolyte sustains a lifespan of 640 h in a symmetric cell, underscoring its effectiveness for high‐energy applications. Full‐cell evaluations with Mo6S8 cathodes further validate the enhanced cycling performance, and the approach proves effective across various conventional Mg salts. These findings position OctylBr as a generally compatible electrolyte additive, unlocking new pathways for high‐performance, long‐life RMBs.

Publisher Copyright

This research / project is supported by the Agency for Science, Technology and Research - Manufacturing, Trade, and Connectivity Programmatic Fund
Grant Reference no. : M23L9b0052

This research / project is supported by the Singapore National Research Foundation - National Research Foundation Investigatorship
Grant Reference no. : NRF-NRFI09-0002

This is the peer reviewed version of the following article: Chinnadurai, D., Kumar, S., Zhang, C., Ng, M., Li, Y., Wang, J., Ghosh, T., Yang, G., Xing, Z., Liu, W., & Seh, Z. W. (2025). Co‐Regulating Planar Mg Deposition and Bromine‐Rich Mg Anode‐Electrolyte Interface by Multifunctional Organic Bromine Additive. Advanced Energy Materials, 15(32). Portico. https://doi.org/10.1002/aenm.202500979 , which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

https://oar.a-star.edu.sg/communities-collections/articles/22360

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Institute of Materials Research and Engineering