High-power Mg batteries enabled by heterogeneous enolization redox chemistry and weakly coordinating electrolytes
High-power Mg batteries enabled by heterogeneous enolization redox chemistry and weakly coordinating electrolytes
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DOI：
10.1038/s41560-020-00734-0
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发表时间：
2020-11-30
期刊：
影响因子：
56.7
通讯作者：
Yao, Yan
中科院分区：
文献类型：
--
作者：
Dong, Hui;Tutusaus, Oscar;Yao, Yan
由于镁离子解离和扩散缓慢，镁基电池具有低功率密度。在这里，作者对阴极和电解质进行了合理的设计，以实现镁金属电池的超快动力学。长期以来，镁电池一直被视为锂离子电池的潜在低成本，高能量和安全的替代品。然而，Mg 2+与电解质溶液和阴极材料强烈相互作用，导致缓慢的离子解离和扩散，并因此导致低功率输出。在这里，我们报告了一个异构烯醇化化学涉及羰基还原（C=O C-O-），绕过解离和扩散的困难，使快速和可逆的氧化还原过程。这种动力学上有利的阴极与定制的、弱配位的基于硼簇的电解质结合，该电解质允许在20 mA cm（-2）的电流密度下进行无枝晶的Mg电镀/剥离。这种组合提供了一种镁电池，其提供高达30.4 kW kg（-1）的比功率，比最先进的镁电池高出近两个数量级。本文阐述的阴极和电解质化学物质推动了镁电池的发展，并将加速这种低成本和安全电池技术的采用。
Owing to sluggish Mg-ion dissociation and diffusion, Mg-based batteries have low power densities. Here the authors carry out rational designs for both the cathode and the electrolyte to enable ultrafast kinetics of a Mg metal battery.Magnesium batteries have long been pursued as potentially low-cost, high-energy and safe alternatives to Li-ion batteries. However, Mg2+ interacts strongly with electrolyte solutions and cathode materials, leading to sluggish ion dissociation and diffusion, and consequently low power output. Here we report a heterogeneous enolization chemistry involving carbonyl reduction (C=O C-O-), which bypasses the dissociation and diffusion difficulties, enabling fast and reversible redox processes. This kinetically favoured cathode is coupled with a tailored, weakly coordinating boron cluster-based electrolyte that allows for dendrite-free Mg plating/stripping at a current density of 20 mA cm(-2). The combination affords a Mg battery that delivers a specific power of up to 30.4 kW kg(-1), nearly two orders of magnitude higher than that of state-of-the-art Mg batteries. The cathode and electrolyte chemistries elucidated here propel the development of magnesium batteries and would accelerate the adoption of this low-cost and safe battery technology.