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Abstract
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To shed light on the stability of hetero-alicyclic ionic-liquids (ILs) as electrolyte in lithium metal batteries, we have computationally studied the electro- chemical windows of twelve distinguished ionic liquids versus Li /Li red-ox pair. Five, six and seven member rings containing nitrogen, phosphorous and arsenic atoms are investigated. The cation set include 1-R-1- methyl pyrrolidinium [RmPyrr] , 1-R-1-methylpiperidinium [RmPiP] , 1-R-1-methyl- ?piperidinium [Rm- ?PiP] , 1-R-1-methylazepanium [RmAzp] with R=MeOCH2CH2- and their phosphonium and arsenium counterparts. [NTF2]- is the common anion in all 12 ionic liquids. DFT calculations1 are exploited to perform the geometrical optimization and free energy calculations in gas and solvated states at B3LYP/6-311 G(d,p) level of theory2. The integral equation formalizm polarizable continuum model (IEF-PCM) is used to account for solvation stabilization3 as implemented in Gaussian09 quantum chemistry package4. In addition to single electron redox reactions, dissociations joined with these reductions and oxidations were investigated. It was found that arsenium compounds are the most stable and seven and five member rings perform better than six member rings. Also, the energetics of the broken of the ether functional was more favorable than other paths. We hope our work provide a novel path in new electrolyte design for lithium metal batteries.
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