Conditioning-Free Electrolytes for Magnesium Batteries Using Sufone–Ether Mixtures with Increased Thermal Stability
Conditioning-Free Electrolytes for Magnesium Batteries Using Sufone–Ether Mixtures with Increased Thermal Stability
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使用具有更高热稳定性的 Sufone-Ether 混合物的镁电池免调节电解质
DOI：
10.1021/acs.chemmater.8b00483
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发表时间：
2018
影响因子：
8.6
通讯作者：
Schaefer, Jennifer L.
中科院分区：
文献类型：
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作者：
Merrill, Laura C.;Schaefer, Jennifer L.
对更高性能和更可持续的电池的需求不断增加，导致了对锂离子电池化学物质的研究。镁金属作为一种新的阳极材料是一种可行的选择，这是由于其广泛的丰度，与锂相比，镁金属在地壳中的丰度约为锂的1000倍，并且镁金属的体积容量高（锂金属为3833 mAh/cm 3，锂金属为2062 mAh/cm 3）。实用的镁金属电池的开发需要开发具有若干特性的电解质，所述特性包括具有普通非活性组分的无腐蚀性、足够宽的电化学稳定性、足够的热稳定性、以高效率电沉积和溶解镁金属的能力、以及促进阴极处可逆电化学行为的能力。1− 3最近，镁电解质的研究几乎完全集中在醚溶剂配方上。4− 6在一些含有较高分子量和更热稳定的醚类（如甘醇二甲醚）的电解质配方中，在电解质分解的循环过程中观察到不可逆性。7，8这被假设是由于较长链甘醇二甲醚的螯合作用，其导致在电荷转移期间去溶剂化之前的分解。在鉴定Mg 2Cl 3+和MgCl+为活性物种的工作中报道了这种效应。7，8最近的一些报告证明了基于砜的镁电解质。9，10砜由于其高沸点和低蒸气压而具有吸引力。先前的研究表明，在早期循环中可逆性较低，并且需要非常负的电位（相对于Mg 2 +/Mg 0小于− 1 V）来诱导镁沉积。9可逆性的改善仅在调节或重复循环伏安法时实现，直到实现可逆行为。我们在本文中报告了基于某些砜/四氢呋喃（THF）混合物的无刘易斯酸的含Mg（HMDS）2− MgCl 2的电解质，相比之下，在低欠电位下显示出镁沉积，在第一次循环中的可逆性高于90%，具有比纯THF对应物高得多的热稳定性。Mg（HMDS）2− MgCl 2配方因其易于从已经商业化的盐制备而特别有吸引力，但迄今为止，该系统仅在THF中显示出高电化学性能，并且在较高沸点醚如甘醇二甲醚中几乎没有溶解性，因此限制了实际应用。11该电解质制剂在甘醇二甲醚/THF混合物中报道;然而，没有观察到显著的镁沉积/剥离。11我们在此报告了通过NMR和质谱研究对砜/THF电解质溶液形态的见解，并表明Mg 2Cl 3+与
Increasing demands for higher performing and more sustainable batteries have led to research in beyond lithium-ion battery chemistries. Magnesium metal serves as a viable option as a new anode material due to its widespread abundance, about 1000 times more abundant in the earth, s crust compared to lithium, and its high volumetric capacity (3833 vs 2062 mAh/cm3 for lithium metal). The development of the practical magnesium metal battery requires development of electrolytes with several characteristics including noncorrosiveness with common inactive components, sufficiently wide electrochemical stability, sufficient thermal stability, ability to electrodeposit and dissolve magnesium metal with high efficiency, and ability to facilitate reversible electrochemical behavior at a cathode. 1− 3Recently, magnesium electrolyte research has focused almost exclusively on ethereal solvent formulations. 4− 6 In some electrolyte formulations containing higher molecular weight and more thermally stable ethers such as glymes, irreversibility is observed during cycling from electrolyte decomposition. 7, 8 This is hypothesized to be due to the chelating effect of longer chain glymes that leads to decomposition prior to desolvation during charge transfer. This effect is reported in works that identify Mg2Cl3+ and MgCl+ as the active species. 7, 8 A few recent reports demonstrated magnesium electrolytes based on sulfones. 9, 10 Sulfones are attractive due to their high boiling points and low vapor pressures. Prior studies showed low reversibility in early cycles, and very negative potentials (less than− 1 V vs Mg2+/Mg0) were required to induce magnesium deposition. 9 Improvement in reversibility was achieved only upon conditioning, or repeated cyclic voltammetry until reversible behavior is achieved. We herein report that Lewis acid-free Mg (HMDS) 2− MgCl2 containing electrolytes based on certain sulfone/tetrahydrofuran (THF) mixtures, in contrast, exhibit magnesium deposition at low underpotentials with reversibilities above 90% on the first cycle, with much higher thermal stability than the pure THF counterpart. The Mg (HMDS) 2− MgCl2 formulation is particularly attractive for its facile preparation from already commercialized salts, but to date this system has shown high electrochemical performance only in THF, and little to no solubility in higher boiling point ethers such as glymes, thus limiting practical application. 11 This electrolyte formulation was reported in glyme/THF mixtures; however, significant magnesium deposition/stripping was not observed. 11 We report here on insights into the sulfone/THF electrolyte solution speciation through NMR and mass spectrometry studies and show that the relative population of Mg2Cl3+ versus
影响因子：
32.5
作者：
Canepa, Pieremanuele;Jayaraman, Saivenkataraman;Ceder, Gerbrand
通讯作者：
Ceder, Gerbrand