Passivation behavior of Type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF6 salt

Abstract

Passivation behavior of type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF 6 salt was studied using electrochemical polarization, X-ray photoelectron spectroscopy (XPS) and time of flight -secondary ion mass spectroscopy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 confirmed by XPS. For complete elimination of the air-formed film, the surface of the stainless steel was scratched under anodic polarization conditions. At 3 V vs. Li/Li + where an anodic current peak appeared, only an indistinct layer was recognized on the newly scratched surface, according to ToF-SIMS analysis. Above 4 V vs. Li/Li + , substantial passive films were formed, which were composed of oxides and fluorides of iron and chromium. The origin of oxide was due to water contained in the non-aqueous alkyl carbonate solution, and that of fluorides were the result of the decomposition of electrolytic salt, LiPF 6 , especially at higher potential. The resultant passive films were stable in the non-aqueous alkyl carbonate solution containing LiPF 6 salt.

Binary iron-chromium oxide as negative electrode for lithium-ion micro-batteries – spectroscopic and microscopic characterization

“…Similarly to the first CV, three main anodic peaks but with lower current density observed at around A 1 = 1.55 V, A 2 = 1.02 V and A 3 = 2.0 V can be assigned to the delithiation process of different valence states of iron oxides according to previous studies [25]. The extra anodic peak at 2.8-3.0 V observed in the second cycle may originate from the oxidation of Fe 0 directly to Fe 3+ as previously reported [42]. However, the corresponding reduction process is not observed in the same potential range, meaning that reduction of Fe 3+ directly to Fe 0 would not occur in the following cathodic process.…”

Effects of Steel Cell Components on Overall Capacity of Pulsed Laser Deposited FeF2Thin Film Lithium Ion Batteries

“…8,17 Thus it is possible that the surface oxide on stainless steel leads is contributing to the measured capacity. Also it was found that 304 steel passivates in the presence of LiPF 6 salt 30 and accordingly may thicken the oxide layer during the cycling which then would contribute the total measured capacity of FeF 2 films. In order to further determine the role of surface oxides from the leads to the total capacity, stainless steel leads of varying sizes were studied in a pouch cell configuration.…”

“…20,22,23 Other investigations reported that aluminum foil was found to be the most suitable material as a current collector for the cathodes in LIBs due to its stability against electrochemical oxidation. 28,29 Another study on 304 stainless steel revealed the formation of a passive layer of (Fe, Cr)-oxide, on which (Cr, Fe)-fluorides reside that would improve the corrosion resistance in the presence of LiPF 6 salt 30 and accordingly it was claimed the possibility of using such steel as applicable current collectors for both positive and negative electrodes, and cell cases for LIBs. 30 Our initial investigation into the capacity of PLD-deposited FeF 2 films resulted in much lower capacities for cells made with aluminum leads compared to stainless steel leads for the same cycling conditions.…”

“…28,29 Another study on 304 stainless steel revealed the formation of a passive layer of (Fe, Cr)-oxide, on which (Cr, Fe)-fluorides reside that would improve the corrosion resistance in the presence of LiPF 6 salt 30 and accordingly it was claimed the possibility of using such steel as applicable current collectors for both positive and negative electrodes, and cell cases for LIBs. 30 Our initial investigation into the capacity of PLD-deposited FeF 2 films resulted in much lower capacities for cells made with aluminum leads compared to stainless steel leads for the same cycling conditions. Although steel and aluminum have been investigated as an anode and cathode, to the authors' knowledge, no reports were found investigating the contribution of steel and/or aluminum leads to the capacity of LIBs.…”

Electrochemical behavior of Al in a non-aqueous alkyl carbonate solution containing LiBOB salt

“…There are some metals (e.g. Cu, Ti, Cr, Fe, type 304 stainless steel) which do not undergo the alloy formation process even in the LiPF 6 salt containing electrolyte [12,13]. Under potential deposition (UPD) of Li is commonly seen for these metal surfaces in the LiPF 6 salt-containing electrolyte [12,13].…”