Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries (RMBs). Herein, a new non-nucleophilic mononuclear electrolyte was developed and its electrochemical active species was identified as [Mg(DME)₃][GaCl₄]₂ through single-crystal X-ray diffraction analysis. The as-synthesized Mg(GaCl₄)₂-IL-DME electrolyte could achieve a high ionic conductivity (9.85 mS cm⁻¹), good anodic stability (2.9 V vs. Mg/Mg²⁺), and highly reversible Mg plating/stripping. The remarkable electrochemical performance should be attributed to the in-situ formation of Mg²⁺-conducting Ga₅Mg₂ alloy layer at the Mg/electrolyte interface during electrochemical cycling, which not only efficiently protects the Mg anode from passivation, but also allows for rapid Mg-ion transport. Significantly, the Mg(GaCl₄)₂-IL-DME electrolyte showed excellent compatibility with both conversion and intercalation cathodes. The Mg/S batteries with Mg(GaCl₄)₂-IL-DME electrolyte and KB/S cathode showed a high specific capacity of 839 mAh g⁻¹ after 50 cycles at 0.1 C with the Coulombic efficiency of ∼100 %. Moreover, the assembled Mg||Mo₆S₈ batteries delivered a reversible discharge capacity of 85 mAh g⁻¹ after 120 cycles at 0.2 C. This work provides a universal electrolyte for the realization of high-performance and practical RMBs, especially Mg/S batteries.

中文翻译：

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在 [Mg（DME）3][GaCl4]2/PYR14TFSI/DME 电解质中原位形成的 Ga5Mg2 合金固体电解质界面可实现高性能可充电镁电池


开发高性能电解液是实现可充电镁电池 （RMBs） 实际应用的关键。在此，开发了一种新的非亲核单核电解质， ₂ 并通过单晶 X 射线衍射分析将其电化学活性物质鉴定为 [Mg（DME） ₃ ][GaCl ₄ ]。合成的 Mg（GaCl ₄ ） ₂ -IL-DME 电解质可实现高离子电导率 （9.85 mS cm ⁻¹ ）、良好的阳极稳定性 （2.9 V vs. Mg/Mg ²⁺ ） 和高度可逆的 Mg 电镀/剥离。显著的电化学性能应归因于电化学循环过程中在 Mg/电解质界面原位形成的 Mg ²⁺ -导电 Ga ₅ Mg ₂ 合金层，这不仅有效地保护了 Mg 阳极免受钝化，而且允许 Mg-离子的快速传输。值得注意的是，Mg（GaCl ₄ ） ₂ -IL-DME 电解质与转化和嵌入阴极均表现出优异的相容性。采用 Mg（GaCl ₄ ） ₂ -IL-DME 电解液和 KB/S 阴极的 Mg/S 电池在 0.1 C 下循环 50 次后显示出 839 mAh g ⁻¹ 的高比容量，库仑效率约为 ∼100 %。此外，组装好的 Mg|| ₆ Mo S ₈ 电池在 0.2 C 下循环 120 次后可提供 85 mAh g ⁻¹ 的可逆放电容量。这项工作为实现高性能和实用的 RMB，尤其是 Mg/S 电池提供了一种通用电解质。