Unlike lithium-ion systems, rechargeable magnesium batteries offer greater volumetric capacity and more abundant resources—yet their anodes have long been hindered by native oxide layers and uneven stripping and plating that reduce cycle life and block scale-up. Now, scientists have created a straightforward protonated organic solvent treatment that eliminates surface oxide, generates a functional magnesium ethoxide interlayer, relieves surface stress, and keeps the anode’s original microstructure intact. The result: symmetric pouch cells operating for over 4,000 cycles and the world’s first 1.07 ampere-hour (Ah) multilayer magnesium pouch cell—a vital advance toward commercial-scale rechargeable magnesium batteries.
The native oxide film (MgO and Mg(OH)₂) that appears on magnesium metal when exposed to air or during processing repeatedly fractures and reforms during battery operation, triggering non-uniform deposition, low coulombic efficiency, and premature failure. Conventional strategies—mechanical grinding, polishing, and acid treatments—either create stress concentrations and defects in the microstructure or remain limited to small-format coin cells. Grinding-generated stress layers can penetrate up to 30 micrometers deep, establishing preferred corrosion sites that quicken degradation. Meanwhile, acid-based methods have had difficulty simultaneously managing interface chemistry and bulk microstructure in a way that extends to practical cell formats. Given these obstacles, a practical approach that stabilizes both the anode interface and the microstructure in a scalable fashion is critically required.
Researchers from Chongqing University and Xiamen University report (DOI: 10.1016/j.esci.2026.100609) in eScience (online June 19, 2026) that a protonated organic solvent treatment—using hydrochloric acid and ethanol—transforms the magnesium anode surface by swapping the native oxide layer for a magnesium ethoxide (Mg(C₂H₅O)₂) interlayer while maintaining a stress-free microstructure. This dual modification enables uniform magnesium stripping and plating, yielding unprecedented cycling stability and the first demonstration of Ah-level performance in a multilayer pouch cell.
The team systematically evaluated acids and solvents, choosing hydrochloric acid in ethanol to treat large-format magnesium foils—yielding batch-processed anodes reaching up to 150 cm × 10 cm in size. Transmission electron microscopy showed the original 4.6 nm MgO layer was replaced by an 8.5 nm magnesium ethoxide layer. Nuclear magnetic resonance spectroscopy confirmed the Mg–O–C bonding, while electron backscatter diffraction revealed that the treated anodes maintained a stress-free microstructure—a sharp contrast to mechanically ground anodes, which displayed stress-concentrated layers roughly 30 μm deep with an average kernel average misorientation (KAM) value of 2.05 versus only 0.18 for the treated anodes.
During cycling, time-of-flight secondary ion mass spectrometry (TOF-SIMS) indicated that the magnesium ethoxide interlayer breaks down and contributes to forming a solid electrolyte interphase (SEI) with markedly lower levels of passivating MgO and Mg(OH)₂ components. Density functional theory (DFT) calculations further showed that magnesium atoms preferentially strip and plate at grain boundaries, where the dissociation energy is 0.73 eV compared to 1.58 eV on grain interiors, and adsorption energy is −1.24 eV versus −0.85 eV. This grain-boundary-guided mechanism, paired with the low-passivation SEI, enabled uniform deposition without dendrites.
“The key insight here is that you can’t just fix the surface — you have to address the microstructure underneath,” the authors said.“Our treatment does both in one simple step: it clears away the problematic oxide, builds a functional interlayer that evolves into a better SEI, and leaves the metal’s grain structure intact so that grain boundaries can do their job as natural nucleation sites. We were surprised to see symmetric pouch cells run for over 4,000 hours, and building a 1.07 Ah multilayer cell — the largest reported for magnesium — really convinced us this approach can scale.”
This study directly tackles the manufacturing bottleneck that has confined magnesium batteries to the laboratory. The simple immersion-based treatment works with roll-to-roll processing, making it industrially feasible for large-scale anode production. When combined with Chevrel-phase Mo₆S₈ cathodes, the treated anodes delivered 1,500 cycles with 79.8% capacity retention at 0.5 C—far exceeding ground anodes, which retained only 14.4%. The Ah-level pouch cell, stacking five cathode sheets and three magnesium foils, achieved 1.07 Ah initial capacity and maintained stable operation over 50 cycles. Beyond grid storage and electric transportation, this breakthrough could speed the commercialization of rechargeable magnesium batteries as a safer, more sustainable alternative to lithium-ion systems.
References
DOI
10.1016/j.esci.2026.100609
Original Source URL
https://doi.org/10.1016/j.esci.2026.100609
Funding information
The work was supported by the National Key R&D Program of China (No. 2023YFB3809500), the Chongqing Technology Innovation and Application Development Project (No. 2024TIAD-KPX0003), and the Xiaomi Young Talents Program.
Lucy Wang
BioDesign Research
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