Key Laboratory of Hydraulic Machinery Transients, Ministry of Education, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
Phys Chem Chem Phys. 2019 Sep 18;21(36):20269-20275. doi: 10.1039/c9cp03836a.
Mg-M (M = Li, Na and K) dual-metal-ion batteries featuring a dendrite-free Mg anode and an alkali-metal-ion storage cathode are promising safe energy storage systems. However, the compatibility between cathode materials and insertion cations might largely limit the electrochemical performance of the cathodes. In this work, three types of Mg-M (M = Li, Na and K) dual-metal-ion batteries are constructed with a Berlin green (FeFe(CN)6) cathode. The FeFe(CN)6 cathode is compatible with the dual-salt Mg2+/M+ (M = Li, Na and K) electrolytes, and delivers a high reversible capacity of 120 mA h g-1 at 50 mA g-1, with no capacity fading over 50 cycles in Mg-Na batteries. The Mg-Na battery also shows an outstanding rate capability, providing 85 mA h g-1 at 1000 mA g-1 and superior long-term cyclability over 800 cycles. The electrochemical performance comparison between Mg-Li, Mg-Na and Mg-K dual-metal-ion batteries demonstrates the significance of the appropriate hydrated ionic radius and dehydrated ionic radius for the insertion of cations with the FeFe(CN)6 cathode. This work provides new design strategies for stable and high energy density cathodes, and opens a new avenue for building safe and high-performance Mg-M (M = Li, Na and K) dual-metal-ion batteries for practical applications.
具有无枝晶 Mg 阳极和碱金属离子存储阴极的 Mg-M（M=Li、Na 和 K）双金属离子电池是很有前途的安全储能系统。然而，阴极材料与插入阳离子之间的兼容性可能会极大地限制阴极的电化学性能。在这项工作中，使用柏林绿（FeFe(CN)6）阴极构建了三种类型的 Mg-M（M=Li、Na 和 K）双金属离子电池。FeFe(CN)6 阴极与双盐 Mg2+/M+（M=Li、Na 和 K）电解质兼容，并在 50 mA g-1 时提供了 120 mA h g-1 的高可逆容量，在 Mg-Na 电池中经过 50 次循环后没有容量衰减。Mg-Na 电池还表现出出色的倍率性能，在 1000 mA g-1 时提供 85 mA h g-1，并且在 800 次循环以上具有优异的长期循环稳定性。Mg-Li、Mg-Na 和 Mg-K 双金属离子电池的电化学性能比较表明，对于具有 FeFe(CN)6 阴极的阳离子的适当水合离子半径和脱水离子半径对于插入具有重要意义。这项工作为稳定且高能量密度阴极提供了新的设计策略，并为构建实用的安全高性能 Mg-M（M=Li、Na 和 K）双金属离子电池开辟了新途径。
