A Stable Solid Electrolyte Interphase for Magnesium Metal Anode Evolved from a Bulky Anion Lithium Salt
A Stable Solid Electrolyte Interphase for Magnesium Metal Anode Evolved from a Bulky Anion Lithium Salt
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由大体积阴离子锂盐演变而来的用于镁金属阳极的稳定固体电解质中间相
DOI：
10.1002/adma.201904987
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发表时间：
2019-12-18
影响因子：
29.4
通讯作者：
Cui, Guanglei
中科院分区：
文献类型：
--
作者：
Tang, Kun;Du, Aobing;Cui, Guanglei
可充电镁（Mg）金属电池因其高容量、高丰度以及最重要的是高度可逆且无枝晶的镁金属阳极而成为“后锂离子电池”的有前途的候选者。然而，镁阳极表面形成钝化表面膜而不是Mg2+导电固体电解质界面(SEI)一直制约着可充电镁电池的发展。通过电化学过程中原始锂电解质的部分分解，在镁金属阳极表面构建了稳定的SEI。这种锂电解质很容易通过将四（六氟异丙氧基）硼酸锂（Li[B(hfip)(4)]）溶解在二甲氧基乙烷中来制备。值得注意的是，在最初的电化学循环过程中，Mg2+可以直接引入到这种Li电解质中，原位形成混合Mg2+/Li+电解质，然后循环电解质可以顺利传导Mg离子。这种形成的SEI的存在阻止了镁金属阳极与电解液的进一步寄生反应，并使该电解液能够稳定地承受长期的电化学循环。这种在镁阳极表面构建优异的SEI并开发新型镁电解质的方法为高性能可充电镁电池的实际应用提供了新途径。
Rechargeable magnesium (Mg) metal batteries are a promising candidate for "post-Li-ion batteries" due to their high capacity, high abundance, and most importantly, highly reversible and dendrite-free Mg metal anode. However, the formation of passivating surface film rather than Mg2+-conducting solid electrolyte interphase (SEI) on Mg anode surface has always restricted the development of rechargeable Mg batteries. A stable SEI is constructed on the surface of Mg metal anode by the partial decomposition of a pristine Li electrolyte in the electrochemical process. This Li electrolyte is easily prepared by dissolving lithium tetrakis(hexafluoroisopropyloxy)borate (Li[B(hfip)(4)]) in dimethoxyethane. It is noteworthy that Mg2+ can be directly introduced into this Li electrolyte during the initial electrochemical cycles for in situ forming a hybrid Mg2+/Li+ electrolyte, and then the cycled electrolyte can conduct Mg-ion smoothly. The existence of this as-formed SEI blocks the further parasitic reaction of Mg metal anode with electrolyte and enables this electrolyte enduring long-term electrochemical cycles stably. This approach of constructing superior SEI on Mg anode surface and exploiting novel Mg electrolyte provides a new avenue for practical application of high-performance rechargeable Mg batteries.