A Novel Regulation Strategy of Solid Electrolyte Interphase Based on Anion‐Solvent Coordination for Magnesium Metal Anode
A Novel Regulation Strategy of Solid Electrolyte Interphase Based on Anion‐Solvent Coordination for Magnesium Metal Anode
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基于阴离子-溶剂配位的镁金属阳极固体电解质界面调控新策略
DOI：
10.1002/smll.202005424
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发表时间：
2020
期刊：
影响因子：
13.3
通讯作者：
Guanglei Cui
中科院分区：
文献类型：
--
作者：
Kun Tang;Aobing Du;Xiaofan Du;Shanmu Dong;Chenglong Lu;Zili Cui;Longshan Li;Guoliang Ding;Fengxian Chen;Xinhong Zhou;Guanglei Cui
镁（Mg）金属负极是各种高能量密度金属负极中非常理想的候选者，与锂金属相比，具有更高的体积容量和更好的安全特性。然而，传统镁电解液中的大多数镁盐很容易与镁金属反应形成阻挡层，导致镁电镀/剥离的可逆性较差。在这里，通过阴离子溶剂配位将分子轨道能级调节到以铝（III）为中心的阴离子镁盐，在镁金属阳极上成功构建了稳定的Mg2+导电固体电解质界面（SEI）。其中，全氟化频哪醇铝酸盐（Al(O2C2(CF3)4)2−，简称FPA）阴离子的LUMO能级通过与溶剂分子（四氢呋喃）配位来调节，以促进有利的SEI的形成。 FPA阴离子形成的SEI的存在极大地提高了镀/退镁过程的可逆性和长期稳定性。更重要的是，基于这种以铝（III）为中心的镁电解质，Mo6S8/镁电池可以实现9000次循环的优异循环性能，证明了SEI对镁电池系统循环稳定性的有益影响。这些发现为在镁金属阳极上构建稳定且相容的SEI开辟了一条有前景的途径，并为可充电镁金属电池的成功开发奠定了重要基础。
Magnesium (Mg) metal anode is a highly desirable candidate among various high energy density metal anodes, possessing higher volumetric capacity and better safety characteristic compared to lithium metal. However, most Mg salts in conventional Mg electrolytes easily react with Mg metal to form blocking layers, leading to inferior reversibility of Mg plating/stripping. Here, a stable Mg2+‐conducting solid electrolyte interphase (SEI) is successfully constructed on Mg metal anode by regulating the molecular‐orbital‐energy‐level toward an aluminum(III)‐centered anion Mg salt through anion‐solvent coordination. Of which, the LUMO energy level of perfluorinated pinacolatoaluminate (Al(O2C2(CF3)4)2−, abbreviated as FPA) anion has been adjusted by coordinating with solvent molecule (tetrahydrofuran) for facilitating the formation of advantageous SEI. The existence of SEI formed by FPA anion greatly improves the reversibility and long‐term stability of Mg plating/stripping process. More importantly, based on this aluminum(III)‐centered Mg electrolyte, the Mo6S8/Mg batteries can achieve a fantastic cycle performance of 9000 cycles, proving the beneficial effect of SEI on the cycling stability of Mg battery system. These findings open up a promising avenue to construct stable and compatible SEI on Mg metal anode, and lay significant foundations for the successful development of rechargeable Mg metal batteries.