Rechargeable magnesium-sodium dual-ion batteries that use dendrite-free magnesium metal as an anode, magnesium-sodium dual-ion electrolyte and sodium-ion cathode are appealing as safe, low-cost systems for large-scale stationary electricity storage. Although substantial advances have been made on magnesium-sodium dual-ion batteries with various sodium-ion cathodes, further development of such batteries is inherently limited by the low electrochemical oxidative stability of known dual-ion electrolytes (2–2.6 V vs. Mg²⁺/Mg). Here, we examine a magnesium-sodium dual-ion concept, which allows for higher operating voltages of magnesium-sodium dual-ion batteries by using oxidatively stable sodium-ion electrolytes along with a sodium-ion conducting β-alumina membrane on the cathode side. The proposed concept is assessed using a high-voltage Na_1.5VPO_4.8F_0.7 cathode demonstrating a high average discharge voltage of 3.0 V, a cathodic capacity of 110 mAh g⁻¹ and an energy efficiency of 90%.

使用无枝晶镁金属作为阳极，镁钠双离子电解质和钠离子阴极的可再充电镁钠双离子电池作为安全，低成本的大型固定式电力存储系统颇具吸引力。尽管具有各种钠离子阴极的镁钠双离子电池已经取得了实质性的进步，但是这种电池的进一步发展固有地受到已知双离子电解质的低电化学氧化稳定性（2-2.6 V vs. Mg ^{2）的限制。 +}/ Mg）。在这里，我们研究了镁钠双离子概念，该概念通过在阴极侧使用氧化稳定的钠离子电解质和钠离子传导性β-氧化铝膜来实现镁钠双离子电池的更高工作电压。使用高压Na _1.5 VPO _4.8 F _0.7阴极评估提出的概念，该阴极显示3.0 V的高平均放电电压，110 mAh g ^-1的阴极容量和90％的能量效率。