Investigation of Li-Ion Solvation in Carbonate Based Electrolytes Using Near Ambient Pressure Photoemission
- 407 Downloads
The near ambient pressure photoemission (NAPP) technique equipped with a liquid jet (LJ) is used for the first time to explore the electronic structure of the most commonly employed carbonate based Li-ion battery electrolytes. Experiments were performed at the SIM beamline of the Swiss Light Source (SLS) with the purpose of monitoring the Li-ion (Li+, Li 1s) solvation of 1M LiClO4 in 1:1 EC:DMC, both anhydrous and with the addition of 5 % H2O, and in DMSO. These electrolytes have high vapor pressures that prevent their study by traditional XPS and therefore necessitate the use of NAPP. Our measurements show differences in binding energies between the Cl 2p and Li 1s core levels (ΔE = Cl 2p3/2−Li 1s) between different solvents, in particularly between the EC:DMC and the DMSO. The addition of only 5 % H2O clearly influences the electronic structure in DMC:EC, but to a lesser extent than completely changing the solvent. Density functional theory (DFT) calculations of solvated Li+ structures within the solvent-separated ion pair (SSIP) model provide support to our experimental findings by revealing that the observed ΔE between solvents is directly related to the change in the electronic structure of the Li+ cation and ClO4 − anion due to the modification of the solvation shell. This study establishes LJ NAPP as a powerful analytical method for the study of Li+ solvation that will prove complementary to the more established approaches of FTIR and NMR, but at the same time will allow for new experiments that cannot yet be realized by FTIR and NMR.
KeywordsLiquid jet Li+ solvation Carbonate based electrolyte Li-ion battery XPS
The NAPP endstation of the Swiss Light Source is supported by PSI and an SNF R’Equip (No. 139139) grant. The authors are grateful to Dr. Armin Kleibert for his tremendous support at the SIM beamline. M.A.B. acknowledges Prof. Nicholas D. Spencer and the LSST at ETH Zürich for continued support. The implementation of the LJ at the SLS benefitted over the years from the continued support and enthusiasm of Prof. M. Ammann and Prof. J. van Bokhoven.
- 1.International Energy Outlook (2013) U.S. Energy Information Administration, DOE/EIA-0484 www.eia.gov/ieo
- 8.Gu M, Parent LR, Mehdi BL, Unocic RR, McDowell MT, Sacci RL, Xu W, Connell JG, Xu P, Abellan P, Chen X, Zhang Y, Perea DE, Evans JE, Lauhon LJ, Zhang JG, Liu J, Browning ND, Cui Y, Arslan I, Wang CM (2013) Demonstration of an electrochemical liquid cell for operando transmission electron microscopy observation of the lithiation/delithiation behavior of Si nanowire battery anodes. Nano Lett 13:6106–6112CrossRefGoogle Scholar
- 16.Lu YC, Crumlin EJ, Veith GM, Harding JR, Mutoro E, Baggetto L, Dudney NJ, Liu Z, Shao-Horn Y (2012) In situ ambient pressure X-ray photoelectron spectroscopy studies of lithium-oxygen redox reactions. Sci Rep 2:715Google Scholar
- 28.Pruyne JG, Lee M-T, Fábri C, Beloqui Redondo A, Kleibert A, Ammann M, Brown MA, Krisch MJ (2014) The liquid-vapor interface of formic acid solutions in salt water: a comparison of macroscopic surface tension and microscopic X-ray photoelectron spectroscopy measurements. J Phys Chem C 118:29350–29360CrossRefGoogle Scholar
- 29.Aurbach D, Zaban A, Ein-Eli Y, Weissman I, Chusid O, Markovsky B, Levi M (1997) Recent studies on the correlation between surface chemistry, morphology, three-dimensional structures and performance of Li and Li-C intercalation anodes in several important electrolyte systems. J Power Sources 68:91–98CrossRefGoogle Scholar
- 31.Flechsig U, Nolting F, Fraile Rodriguez A, Krempasky J, Quitmann C, Schmidt T, Spielmann S, Zimoch D (2010) Performance measurements at the SLS SIM beamline. AIP Conf Proc 1234:319–322Google Scholar
- 34.Brown MA, Beloqui Redondo A, Jordan I, Duyckaerts N, Lee M-T, Ammann M, Nolting F, Kleibert A, Huthwelker T, Machler J-P, Birrer M, Honegger J, Wetter R, Wörner HJ, Van Bokhoven JA (2013) A new endstation at the Swiss Light Source for ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy measurements of liquid solutions. Rev Sci Instrum 84:073904CrossRefGoogle Scholar
- 37.Hermann K, Pettersson LGM, Casida ME, Daul C, Goursot A, Koester A, Proynov E, St-Amant A, Salahub DR, Carravetta V, Duarte A, Godbout N, Guan J, Jamorski C, Leboeuf M, Leetmaa M, Nyberg M, Pedocchi L, Sim F, Triguero L, Vela A (2005) StoBe-deMon, deMon Software. Stockholm, BerlinGoogle Scholar
- 42.Solvent vapor pressure, EC: 0.01 mmHg (25 °C), DMC: 18 mmHg (21 °C) and DMSO: 0.4 mmHg (20 °C) http://pubchem.ncbi.nlm.nih.gov Open chemistry database
- 46.Laurence C, Gal JF (2010) Lewis basicity and affinity scales data and measurement (chapter 2). Wiley, HobokenGoogle Scholar