In Situ Atomic Force Microscopy and Electrochemical Quartz Crystal Microbalance Studies on the Electrodeposition and Oxidation of Silicon

Abstract

In this paper, we investigated how the anion of an ionic liquid (IL) affects nanostructure of electrode/electrolyte interface and subsequently the deposition process of silicon. For this purpose, ILs with the same cation 1-butyl-1-methylpyrrolidinium and various anions, namely, tris­(pentafluoroethyl) trifluorophosphate ([Py1,4]­FAP), bis­(trifluoromethylsulfonyl)­amide ([Py1,4]­TFSA), and bis­(fluorosulfonyl)­amide ([Py1,4]­FSA) were chosen. Cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) were used to study the electrochemical processes. Raman spectroscopy and in situ atomic force microscopy (AFM) were used to evaluate the changes in the ILs on addition of SiCl4 and to probe the changes in the Au (111)/electrolyte interface, respectively. From cyclic voltammetry and EQCM measurements, it was found that the electrochemical processes changed significantly on changing the anion. However, from Raman spectroscopy a few spectral changes related to vibrational modes of the employed anions were observed on addition of SiCl4 to the ILs. In situ AFM studies revealed that on changing the anions and on applying a negative electrode potential, the number of solvation layers and their corresponding widths changed in the presence of SiCl4. Although silicon thin films could be electrodeposited from all of the three ILs at room temperature, the best deposit was obtained from [Py1,4]­TFSA.

Silicon and Iron as Resource-Efficient Anode Materials for Ambient-Temperature Metal-Air Batteries: A Review

“…Considering primary applications, silicon-based batteries from scrap material could be a decent option to replace primary Zn-air batteries in the future, given the excellently flat and long-lasting discharge characteristics of silicon in comparison to zinc. Furthermore, similar to Ca-O 2 batteries, it does not appear ultimately impossible to tackle the missing rechargeability of Si-air batteries [106,107,108], which is effected by thermodynamics and exemplarily explained with the help of polarization curves in comparison to rechargeable Fe-air batteries in Figure 6.…”

Silicon and Iron as Resource-Efficient Anode Materials for Ambient-Temperature Metal-Air Batteries: A Review

“…Considering primary applications, silicon-based batteries from scrap material could be a decent option to replace primary Zn-air batteries in the future, given the excellently flat and long-lasting discharge characteristics of silicon in comparison to zinc. Furthermore, similar to Ca-O2 batteries, it does not appear ultimately impossible to tackle the missing rechargeability of Si-air batteries [106][107][108], which is effected by thermodynamics and exemplarily explained with the help of polarization curves in comparison to rechargeable Fe-air batteries in Figure 6. Based on thermodynamic considerations, the currently missing reversibility of Si-air batteries compared to other metal-air systems arises from two major issues.…”

“…While the equilibrium potential of silicon in EMIm(HF)2.3F lies well within the stability window of the electrolyte, the RTIL might easily decompose upon recharge, if the reduction potential is shifted to critically low values. The electrochemical deposition of Si in other RTILs have already been reported [106][107][108], which might enable the rechargeability of Si also on a battery level in near future.…”

A Review on the Electroless Deposition of Functional Materials in Ionic Liquids for Batteries and Catalysis

“…As only ions are present in ionic liquids, by changing the anions of the ionic liquids, the speciation of metals/semiconductor ions can be altered (Borisenko et al, 2018; Lahiri et al, 2018a). A change in the speciation leads to a different electrochemical behavior and has also shown to affect the morphology of the deposit (Pulletikurthi et al, 2013, 2014; Borisenko et al, 2018; Lahiri et al, 2018a).…”

“…As only ions are present in ionic liquids, by changing the anions of the ionic liquids, the speciation of metals/semiconductor ions can be altered (Borisenko et al, 2018; Lahiri et al, 2018a). A change in the speciation leads to a different electrochemical behavior and has also shown to affect the morphology of the deposit (Pulletikurthi et al, 2013, 2014; Borisenko et al, 2018; Lahiri et al, 2018a). Interestingly, it was reported that changing the cations of the ionic liquids also affects the morphology of the electrodeposits (Zein El Abedin et al, 2006; Al-Salman and Endres, 2009; Ispas et al, 2010).…”