Ionic liquid hybrids: Progress toward non-corrosive electrolytes with high-voltage oxidation stability for magnesium-ion based batteries

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• 作者：Matthew M. Huie^a ; Christina A. Cama^b ; Paul F. Smith^b ; Jiefu Yin^b ; Amy C. Marschilok^a ; ^b ; ^{amy.marschilok@stonybrook.edu" class="auth_mail" title="E-mail the corresponding author} ; Kenneth J. Takeuchi^a ; ^b ; ^{kenneth.takeuchi.1@stonybrook.edu" class="auth_mail" title="E-mail the corresponding author} ; Esther S. Takeuchi^a ; ^b ; ^c ; ^{esther.takeuchi@stonybrook.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：magnesium-ion battery ; ionic liquid electrolyte ; electrolyte oxidation ; electrolyte conductivity ; high-voltage Mg-ion cathode
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：20 November 2016
• 年：2016
• 卷：219
• 期：Complete
• 页码：267-276
• 全文大小：1917 K

文摘

Magnesium – ion batteries have the potential for high energy density but require new types of electrolytes for practical application. Ionic liquid (IL) electrolytes offer the opportunity for increased safety and broader voltage windows relative to traditional electrolytes. We present here a systematic study of both the conductivity and oxidative stability of hybrid electrolytes consisting of eleven ILs mixed with dipropylene glycol dimethylether (DPGDME) or acetonitrile (ACN) cosolvents and magnesium bis(trifluoromethylsulfonyl)imide (Mg(TFSI)₂). Our study finds a correlation of higher conductivity of ILs with unsaturated rings and short carbon chain lengths, but by contrast, these ILs also exhibited lower oxidation voltage limits. For the cosolvent additive, although glymes have a demonstrated capability of coordination with Mg²⁺ ions, a decrease in conductivity compared to acetonitrile hybrid electrolytes was observed. When cycled within the appropriate voltage range, the IL-hybrid electrolytes that show the highest conductivity provide the best cathode magnesiation current densities and lowest polarization as demonstrated with a Mg_0.15MnO₂ and Mg_0.07V₂O₅ cathodes.