Electrochemistry of Magnesium Electrolytes in Ionic Liquids for Secondary Batteries
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- 作者：Gulin Vardar ; Alice E. S. Sleightholme ; Junichi Naruse ; Hidehiko Hiramatsu ; Donald J. Siegel ; Charles W. Monroe
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：October 22, 2014
- 年：2014
- 卷：6
- 期：20
- 页码：18033-18039
- 全文大小：291K
- ISSN：1944-8252
文摘
The electrochemistry of Mg salts in room-temperature ionic liquids (ILs) was studied using plating/stripping voltammetry to assess the viability of IL solvents for applications in secondary Mg batteries. Borohydride (BH4鈥?/sup>), trifluoromethanesulfonate (TfO鈥?/sup>), and bis(trifluoromethanesulfonyl)imide (Tf2N鈥?/sup>) salts of Mg were investigated. Three ILs were considered: l-n-butyl-3-methylimidazolium (BMIM)-Tf2N, N-methyl-N-propylpiperidinium (PP13)-Tf2N, and N,N-diethyl-N-methyl(2-methoxyethyl)ammonium (DEME+) tetrafluoroborate (BF4鈥?/sup>). Salts and ILs were combined to produce binary solutions in which the anions were structurally similar or identical, if possible. Contrary to some prior reports, no salt/IL combination appeared to facilitate reversible Mg plating. In solutions containing BMIM+, oxidative activity near 0.8 V vs Mg/Mg2+ is likely associated with the BMIM cation, rather than Mg stripping. The absence of voltammetric signatures of Mg plating from ILs with Tf2N鈥?/sup> and BF4鈥?/sup> suggests that strong Mg/anion Coulombic attraction inhibits electrodeposition. Cosolvent additions to Mg(Tf2N)2/PP13-Tf2N were explored but did not result in enhanced plating/stripping activity. The results highlight the need for IL solvents or cosolvent systems that promote Mg2+ dissociation.