Synthesis, Characterization, and Electrochemical Investigation of Li[O2P(OCH2CF3)2] and Li[O2P{OC(H)(CF3)2}2] and Use of the Former for Coordination‐Polymer‐Based Gel Electrolytes

Schleep, Mario; Reininger, Stefanie; Eiden, Philipp; Klose, Petra; Schulz, Christoph; Scherer, Harald; Laule, Stephan; Bodendorfer, Simon; Schmidt, Michael A.; Garsuch, Arnd; Krossing, Ingo

doi:10.1002/celc.201500560

Cited by 5 publications

(12 citation statements)

References 18 publications

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“…11,21,22 2 ], also referred to as LiBFEP; see E in Scheme 1) has been used as a coordinationpolymer-based gel electrolyte in our recent work. 32 LiBFEP forms a viscous gel in EC/DMC (1/1 g:g) at 0.5 M with a rather low conductivity of 41.8 μS·cm −1 at room temperature. However, when added to 1 M LiPF 6 in EC/DMC (1/1 g:g), also referred to as LP30, the conductivity of the electrolyte is largely retained within the range of 6.0 mS·cm …”

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Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells

Milien

Beyer

Beichel

et al. 2018

J. Electrochem. Soc.

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The fluorinated phosphate lithium bis (2,2,2-trifluoroethyl) phosphate (LiBFEP) has been investigated as a film-forming additive employed to passivate the cathode and hinder continuous oxidation of the electrolyte. Cyclic voltammetry (CV) and linear sweep voltammetry coupled with online electrochemical mass spectrometry (LSV-OEMS) on a conductive carbon electrode (i.e., a C65/PVDF composite) showed that LiBFEP decreases electrolyte oxidation (CV and LSV) and LiPF 6 decomposition at high potentials. Incorporation of LiBFEP (0.1 and 0.5 wt%) into LiPF 6 in ethylene carbonate (EC)/ethyl methyl carbonate (EMC) (3:7 wt) results in improved coulombic efficiency and capacity retention for LNMO/graphite cells. Ex-situ surface analysis of the electrodes suggests that incorporation of LiBFEP results in the formation of a cathode electrolyte interface (CEI) and modification of the solid electrolyte interface (SEI) on the anode. The formation of the CEI mitigates electrolyte oxidation and prevents the decomposition of LiPF 6 , which in turn prevents HF-induced manganese dissolution from the cathode and destabilization of the SEI. The passivation of the cathode and stabilization of the SEI is responsible for the increased coulombic efficiency and capacity retention. Since their debut in 1991, lithium ion batteries (LIB) have become the universal power source for consumer electronics.1 Larger format LIBs such as those needed to power electric vehicles (EVs), an important future market, have amassed considerable interest; however higher specific energy densities are required for larger format LIBs.1,2 The practical way to increase energy density is to employ cathode materials with increased theoretical capacities and/or high discharge plateaus, and thus high energy (HE) or high voltage (HV) cathodes are required in order for LIBs to meet the demands of the EV market.3 While both HE and HV cathodes have been implemented, current research efforts are focused on overcoming the caveats associated with these materials. The oxidative instability of carbonate-based electrolytes is a central limitation for cells with various cathode chemistries operated above 4.4 V. [3][4][5][6][7] In addition to the instability of the electrolyte, cathodes such as nickel-rich layered oxides (LiNi x Mn y Co z O 2 ), lithium-rich layered oxides (0.6 Li 2 MnO 3 • 0.4 Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 ), and HV spinel (LiNi 0.5 Mn 1.5 O 4 ) (LNMO) all suffer from structural instability when operated at high potentials.5-11 While the layered oxides are capable of delivering higher practical energy densities, the lack of cobalt in LNMO alleviates the issues of cost and resource limitations.7 As the higher energy densities associated with HE materials can only be obtained at higher cutoff potentials, oxidation of the electrolyte is a universal problem to both HE and HV cathodes. This work focuses on improving the performance of LNMO/Graphite cells.The capacity fading observed in LNMO/Graphite cells is due to continuous oxidation of the electrolyte and transition...

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Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells

Milien

Beyer

Beichel

et al. 2018

J. Electrochem. Soc.

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“…However, in a EC/EMC mixture (ethylene carbonate/ethyl methyl carbonate, 3:7 wt), 3 is soluble up to 0.6 mol · L –1 . The solution displays a conductivity of 5.2 mS · cm –1 at that concentration, which is not too far from the conductivity of a 1 m solution of Li[PF 6 ] in this carbonate mixture (7.48 mS · cm –1 ) (Figure ).…”

Section: Resultsmentioning

confidence: 80%

Perfluorinated tert‐Butoxides of Tin(II): The Dimeric Alkoxide and Its Monomeric Ate Complex

Schleep

Hettich

Glatz

et al. 2018

Zeitschrift anorg allge chemie

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“…This is about three times higher than that of the optimized LP 30 LIB electrolyte (10.25 mS cm −1 @ 1.0 mol L −1 Li[PF 6 ] in EC/ DMC 1:1). [55] According to the Walden plots in Figure 5, salts more detailed because of the higher ionicity and the better comparability to the EL MeCN-BMP-Cl-30 . Besides, the conductivity of EL GBL-BMP-Cl-50 (6.1 mS cm −1 at 31 °C) still lies at the bottom of the range of liquid electrolytes used in LIBs.…”

Section: Conductivity Viscosity and Ionicitymentioning

confidence: 99%

Investigations toward a Non‐Aqueous Hybrid Redox‐Flow Battery with a Manganese‐Based Anolyte and Catholyte

Schmucker

Gully

Schmidt

et al. 2021

Advanced Energy Materials

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The importance of electrical energystorage systems (EES), for a successful integration of intermittent renewable energy sources into the electrical grid is beyond dispute. [1][2][3][4] For mobile applications, lithium ion batteries (LIBs) with high energy density prevail. [2,5,6] Although many efforts focus on alternative chemical systems (e.g., multivalent Al, Mg, and Ca), it is hard to imagine that LIBs will disappear in the near future. [4,7] Yet, for large scale stationary EES, there is no such prevailing technology. Although other alternatives, like pumped hydro or fuel cells are available, batteries are amongst the most promising technologies for this purpose. [1,3,8] With the energy density being slightly less relevant, other redox active materials could be employed in large scale EES, i.e., redox-flow batteries (RFBs) with their very long cycle life and decoupled capacity, power and energy output. [2,9,10] Their benchmark is the allvanadium redox-flow battery (VRFB) with V II /V III and V IV / V V redox couples, [2] as well as a 15 000-20 000 charge/discharge cycles lifetime and an acceptable energy density of 25-35 Wh L −1 installed in up to 60 MWh capacity EES. [2,6] However, probably due to the high cost, a commercial breakthrough still has to come. [2,6,9] Considering abundancy and cost, few elements are suitable as redox active material in sustainable batteries. [4,11] Manganese is one of them and, therefore, finds application in LIB-cathode active materials (e.g., LiMn 2 O 4 or Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 ) or in cathode materials of primary batteries (MnO 2 ). [5,12] However, to the best of our knowledge, only one battery system exclusively using manganese compounds at both electrodes is described, [13] i.e., Mn(acac) 3 acetonitrile (MeCN) solutions with the Mn II /Mn III couple at the negative and the Mn III /Mn IV couple at the positive electrode. Yet, with E cell of 1.1 V the system does not exploit the large potential range advantage of a non-aqueous electrolyte. Already the aqueous standard potential difference ΔE 0 of Mn 0 /Mn II and Mn II /Mn III redox couples amounts to an impressive 2.69 V. In addition, the Mn volumetric specific capacity is 7034.7 Ah L −1 (two-electron-process). It clearly exceeds that of zinc (5853.8 Ah L −1 ), which in the zinc A new all-Manganese flow battery (all-MFB) as a non-aqueous hybrid redox-flow battery is reported. The discharged active material [Cat] 2 [Mn II Cl 4 ] (Cat = organic cation) utilized in both half-cells supports a long cycle life. The reversible oxidation of [Mn II Cl 4 ] 2− to [Mn III Cl 5 ] 2− at the positive electrode and manganese metal deposition from [Mn II Cl 4 ] 2− at the negative electrode give a cell voltage of 2.59 V. Suitable electrolytes are prepared and optimized, followed by a characterization in static battery cells and in a pumped flow-cell. Several electrode materials, solvents, and membranes are tested for their feasibility in the all-MFB. An electrolyte consisting of [EMP] 2 [MnCl 4 ] and some solvent γ-butyrolactone is cycle...

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Synthesis, Characterization, and Electrochemical Investigation of Li[O₂P(OCH₂CF₃)₂] and Li[O₂P{OC(H)(CF₃)₂}₂] and Use of the Former for Coordination‐Polymer‐Based Gel Electrolytes

Cited by 5 publications

References 18 publications

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells

Perfluorinated tert‐Butoxides of Tin(II): The Dimeric Alkoxide and Its Monomeric Ate Complex

Investigations toward a Non‐Aqueous Hybrid Redox‐Flow Battery with a Manganese‐Based Anolyte and Catholyte

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Synthesis, Characterization, and Electrochemical Investigation of Li[O2P(OCH2CF3)2] and Li[O2P{OC(H)(CF3)2}2] and Use of the Former for Coordination‐Polymer‐Based Gel Electrolytes

Cited by 5 publications

References 18 publications

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O2P(OCH2CF3)2]: A High Voltage Additive for LNMO/Graphite Cells

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O2P(OCH2CF3)2]: A High Voltage Additive for LNMO/Graphite Cells

Perfluorinated tert‐Butoxides of Tin(II): The Dimeric Alkoxide and Its Monomeric Ate Complex

Investigations toward a Non‐Aqueous Hybrid Redox‐Flow Battery with a Manganese‐Based Anolyte and Catholyte

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Synthesis, Characterization, and Electrochemical Investigation of Li[O₂P(OCH₂CF₃)₂] and Li[O₂P{OC(H)(CF₃)₂}₂] and Use of the Former for Coordination‐Polymer‐Based Gel Electrolytes

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O₂P(OCH₂CF₃)₂]: A High Voltage Additive for LNMO/Graphite Cells