Enhanced Sodium Metal Anode Cycling Stability via an Organometallic Electrolyte Additive
Abstract
Despite the high theoretical capacity of sodium metal anodes, practical application is limited by the general instability of the solid-electrolyte interphase (SEI) leading to dendritic growth and capacity fade. Here we report that the dimolybdenum paddlewheel complex, Mo2(mea)4 (1, mea = 2-(2-methoxyethoxy)acetate), functions as an effective electrolyte additive for Na metal anodes at millimolar loadings, enabled by self-assembly on the anode surface upon formation of aggregates involving 1 and Na+. In symmetric Na||Na cells, additive 1 was found to increase cycling stability and attenuate overpotential growth and impedance rise over 450 cycles compared to additive-free controls. X-ray photoelectron spectroscopy revealed that 1 promotes early formation of an inorganic-rich SEI that also contains intact 1 and its downstream products. Scanning electron microscopy confirmed suppression of morphologies associated with dendrite growth. Full-cell Na||Na3V2(PO4)3 testing demonstrated improved Coulombic efficiency relative to an additive-free control and served to validate cathode compatibility of the additive. This work establishes organometallic complexes as an effective “third class” of Na metal battery additives, complementing purely organic or inorganic systems.
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BibTeX
@misc{subasinghe2026enhanced,
title = {{Enhanced Sodium Metal Anode Cycling Stability via an Organometallic Electrolyte Additive}},
author = {S. M. Supundrika Subasinghe and Bhavya N. Vira and A. A. P. R. Perera and Simon G. Gersib and Jordi Cabana and Neal P. Mankad},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010282/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010282/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Enhanced Sodium Metal Anode Cycling Stability via an Organometallic Electrolyte Additive
AU - S. M. Supundrika Subasinghe
AU - Bhavya N. Vira
AU - A. A. P. R. Perera
AU - Simon G. Gersib
AU - Jordi Cabana
AU - Neal P. Mankad
PY - 2026
DA - 2026/10/12
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010282/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010282/v1
AB - Despite the high theoretical capacity of sodium metal anodes, practical application is limited by the general instability of the solid-electrolyte interphase (SEI) leading to dendritic growth and capacity fade. Here we report that the dimolybdenum paddlewheel complex, Mo2(mea)4 (1, mea = 2-(2-methoxyethoxy)acetate), functions as an effective electrolyte additive for Na metal anodes at millimolar loadings, enabled by self-assembly on the anode surface upon formation of aggregates involving 1 and Na+. In symmetric Na||Na cells, additive 1 was found to increase cycling stability and attenuate overpotential growth and impedance rise over 450 cycles compared to additive-free controls. X-ray photoelectron spectroscopy revealed that 1 promotes early formation of an inorganic-rich SEI that also contains intact 1 and its downstream products. Scanning electron microscopy confirmed suppression of morphologies associated with dendrite growth. Full-cell Na||Na3V2(PO4)3 testing demonstrated improved Coulombic efficiency relative to an additive-free control and served to validate cathode compatibility of the additive. This work establishes organometallic complexes as an effective “third class” of Na metal battery additives, complementing purely organic or inorganic systems.
ER -