Ionic Liquids Electrodeposition of Sn with Different Structures as Anodes for Lithium-Ion Batteries

Abstract

Electrodeposition of tin (Sn) on a Ni electrode has been investigated in three ionic liquids, i.e., 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm]BF 4 ), 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) and 1-ethyl-3-methylimidazolium dicyanamide ([EMIm]DCA). Sn(II) ion was introduced into the ionic liquids by dissolving SnCl 2 . The different redox potentials of the Sn(II)/Sn couple imply that different Sn(II) species were formed in these solvents. Voltammetric studies reveal that the reduction of Sn(II) in these systems involves a diffusion-controlled irreversible process. The microstructure of the Sn electrodeposits can be significantly influenced by altering the anion of the ionic liquids and the electrodeposition potential. The electrochemical performances of the as-prepared Sn electrodeposits as anodes for lithium-ion batteries were studied. The Sn electrode electrodeposited in [EMIm]DCA ionic liquid shows a high discharge/charge capacity of 515 and 502 mAh g −1 after 50 cycles at 0.1 A g −1 . The cycling performance is evidently better than those of the Sn electrodes obtained in [EMIm]BF 4 and [EMIm]TfO ionic liquids.

Sn(TFSI)2as a suitable salt for the electrodeposition of nanostructured Cu6Sn5–Sn composites obtained on a Cu electrode in an ionic liquid

“…The non-zero intercept may be assigned to an adsorption phenomena and some surface chemical coupled reactions. 29,43 The diffusion coefficient of Sn 2+ species, 27,29,30 probably due to higher viscosity for [EMIm + ][TFSI -] that induced a lower mobility of Sn 2+ . Moreover, because the coordination state of Sn 2+ is modified by the counter ion solvation force of the ionic liquid anion versus the counter-ion of Sn precursor, different solvation environments influencing Sn 2+ mobility are expected.…”

“…The multi-step lithiation delithiation processes on Sn electrode 3,29,44 as on Sn based alloy electrode 29,[45][46][47][48] are already well documented, and it has already been concluded that CV profiles and peak potentials are in both cases characteristic of electrodes containing metallic tin. Especially the plateau of potential attributed to the lithiation of Cu6Sn5 arise in the same domain of potential where intermetallic tin-lithium phases prevails.…”

“…23 Even if experimental deposition conditions modulate the morphology, the thickness, and the nanostructuration of the deposited layer, in this kind of synthesis, they are also dramatically influenced by the choice of the anion/cation combination of the IL 19,[24][25][26][27] Indeed the physicochemical properties of the solvent (conductivity, solubility, viscosity) impact the deposition potentials the and the electrodeposition mechanism. In the case of Sn deposit, some studies have already underline the influence of the anion 24,[26][27][28][29] through viscosity and stabilization of the precursor tin species from one part. From another part, the influence of the ionic liquid cation through viscosity and likely its different adsorption /interactions with the substrate or the nuclei was also demonstrated [26][27][28] .…”

The Effect of Water on the Tin Electrodeposition from [Bmim]HSO4 Ionic Liquid

“…The electrochemical deposition of tin and its alloys is of great practical importance and widely used in the semiconductor industry and field of energy storage devices [1][2][3][4], like lithium ion batteries; e.g., traditional electrodeposition of tin and its alloy is performed in aqueous electrolytes including sulfate, fluoborate, and citrate [5][6][7]. Such electrolytes are susceptible to complex electrolyte composition and quite corrosive and can possibly have a negative impact on the environment.…”

“…The electrodeposition of tin has been investigated in some ionic liquids [4,14], especially AlCl 3 -based ionic liquids [15]. However, this kind of ionic liquid is sensitive to air and water; therefore the experiment must be carried out under inert gas conditions.…”