Toward waterproof magnesium metal anodes by uncovering water-induced passivation and drawing water-tolerant interphases.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39478049.
- Also identified by DOI 10.1038/s41467-024-53796-z and PMC identifier 11525818.
- Licence recorded as CC BY-NC-ND.
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Abstract
Magnesium (Mg) metal is a promising anode candidate for high-energy and cost-effective multivalent metal batteries, but suffers from severe surface passivation in conventional electrolytes, especially aqueous solutions. Here, we uncover that MgH<sub>2</sub>, in addition to the well-known MgO and Mg(OH)<sub>2</sub>, can be formed during the passivation of Mg by water. The formation mechanism and spatial distribution of MgH<sub>2</sub>, and its detrimental effect on interfacial dynamics and stability of Mg anode are revealed by comprehensive experimental and theoretical investigations. Furthermore, a graphite-based hydrophobic and Mg<sup>2+</sup>-permeable water-tolerant interphase is drawn using a pencil on the surface of Mg anodes, allowing them to cycle stably in symmetric (> 900 h) and full cells (> 500 cycles) even after contact with water. The mechanistic understanding of MgH<sub>2</sub>-involved Mg passivation and the design of pencil-drawn waterproof Mg anodes may inspire the further development of Mg metal batteries with high water resistance.