PROCESS FOR MAKING A CATHODE, AND INTERMEDIATES SUITABLE THEREFOR

Abstract

Process for making a cathode comprising the following steps (a) Providing a cathode active material selected from layered lithium transition metal oxides, lithiated spinels, lithium transition metal phosphate with olivine structure, and lithium nickel-cobalt aluminum oxides, (b) treating said cathode active material with an oligomer bearing units according to general formula (I a),

##STR00001## wherein R.sup.1 are the same or different and selected from hydrogen and C.sub.1-C.sub.4-alkyl, aryl, and C.sub.4-C.sub.7-cycloalkyl, R.sup.2 and R.sup.3 are selected independently at each occurrence from phenyl and C.sub.1-C.sub.8-alkyl, C.sub.4-C.sub.7-cycloalkyl, C.sub.1-C.sub.8-haloalkyl, OPR.sup.1(O)—*, and —(CR.sup.9.sub.2).sub.p—Si(R.sup.2).sub.2—* wherein one or more non-vicinal CR.sup.9.sub.2-groups may be replaced by oxygen, R.sup.9 is selected independently at each occurrence from H and C.sub.1-C.sub.4-alkyl, and p is a variable from zero to 6, and wherein the overall majority of R.sup.2 and R.sup.3 is selected from C.sub.1-C.sub.8-alkyl, and, optionally, at least one of carbon in electrically conductive form and, optionally, a binder, (c) applying a slurry of said treated cathode active material to a current collector, and (d) at least partially removing solvent used in step (c).

Claims

1-15. (canceled)

16. A process for making a cathode, the process comprising: providing a cathode active material selected from the group consisting of a layered lithium transition metal oxide, a lithiated spinel, a lithium transition metal phosphate with an olivine structure, and a lithium nickel-cobalt aluminum oxide, treating the cathode active material with an oligomer and optionally a carbon in an electrically conductive form and optionally a binder to form a treated cathode active material, wherein the oligomer comprises units of the formula (I a), ##STR00015## wherein each R.sup.1 is selected independently from the group consisting of a hydrogen, a C.sub.1-C.sub.4-alkyl, an aryl, and a C.sub.4-C.sub.7-cycloalkyl, wherein R.sup.2 and R.sup.3 are each selected independently at each occurrence from the group consisting of a phenyl, a C.sub.1-C.sub.8-alkyl, a C.sub.4-C.sub.7-cycloalkyl, a C.sub.1-C.sub.8-haloalkyl, an OPR.sup.1(O)—*, and a —(CR.sup.9.sub.2).sub.p—Si(R.sup.2).sub.2—*, wherein: one or more non-vicinal CR.sup.9.sub.2-groups may be replaced by oxygen; R.sup.9 is selected independently at each occurrence from H and C.sub.1-C.sub.4-alkyl; and p is a number from 0 to 6; wherein an overall majority of R.sup.2 and R.sup.3 is a C.sub.1-C.sub.8-alkyl, and wherein each * is selected independently from the group consisting of an additional unit of formula (I a), an end-cap R.sup.4 wherein R.sup.4 is a C.sub.1-C.sub.4-alkyl, and a branching, applying a slurry comprising the treated cathode active material and a solvent to a current collector to form a treated current collector, and removing the solvent at least partially from the treated current collector to form the cathode.

17. The process of claim 16, wherein the oligomer comprises an average of at least two P atoms per molecule.

18. The process of claim 16, wherein each R.sup.1 is independently hydrogen or methyl, and wherein all R.sup.2 and R.sup.3 are methyl.

19. The process of claim 16, wherein the treating is performed at a temperature in a range of from 5° C. to 200° C.

20. The process of claim 16, wherein the oligomer is end-capped with one or more O—R.sup.4 groups, wherein R.sup.4 is a C.sub.1-C.sub.4-alkyl.

21. The process of claim 16, wherein the applying is performed with a squeegee or an extruder.

22. The process of claim 16, wherein the oligomer is in contact with an aprotic solvent during the treating, and wherein the aprotic solvent has a boiling point at normal pressure in a range of from 25° C. to 250° C.

23. The process of claim 16, further comprising, before the treating: mixing the oligomer with the carbon in an electrically conductive form, an aprotic solvent, and optionally a binder.

24. The process of claim 16, wherein the cathode active material is a layered lithium transition metal oxide and/or a lithium nickel-cobalt aluminum oxide.

25. A cathode active material at least one selected from the group consisting of a layered lithium transition metal oxide, a lithiated spinel, a lithium transition metal phosphate with an olivine structure, and a lithium nickel-cobalt aluminum oxide; and comprising a coating, wherein the coating is present at a weight percentage in a range of 0.1-4 wt % relative to a total weight of the cathode active material, and wherein the coating comprises P and Si having a P to Si mass ratio in a range of 1:1 to 1.8:1.

26. The cathode active material of claim 25, wherein the coating comprises units of the formula (I a), ##STR00016## wherein each R.sup.1 is selected independently from the group consisting of a hydrogen, a C.sub.1-C.sub.4-alkyl, an aryl, and a C.sub.4-C.sub.7-cycloalkyl, wherein R.sup.2 and R.sup.3 are each selected independently at each occurrence from the group consisting of a phenyl, a C.sub.1-C.sub.8-alkyl, a C.sub.4-C.sub.7-cycloalkyl, a C.sub.1-C.sub.8-haloalkyl, an OPR.sup.1(O)—*, and a —(CR.sup.9.sub.2).sub.p—Si(R.sup.2).sub.2—*, wherein: one or more non-vicinal CR.sup.9.sub.2-groups may be replaced by oxygen; R.sup.9 is selected independently at each occurrence from H and C.sub.1-C.sub.4-alkyl; and p is a number from 0 to 6; wherein an overall majority of R.sup.2 and R.sup.3 is a C.sub.1-C.sub.8-alkyl, and wherein each * is selected independently from the group consisting of an additional unit of formula (I a), an end-cap R.sup.4 wherein R.sup.4 is a C.sub.1-C.sub.4-alkyl, and a branching.

Description

I. Synthesis

[0182] General Remarks:

[0183] All compounds were analyzed using .sup.1H NMR spectroscopy and .sup.31P NMR spectroscopy directly after preparation. Samples were prepared and measured under inert atmosphere using CDCl.sub.3 (7.26 ppm) as a reference; when inventive oligomers were analyzed screw-cap NMR tubes were used equipped with an inner tube filled with C.sub.6D.sub.6 as reference (7.16 ppm). The spectra were recorded on a Bruker Avance III equipped with a CryoProbe Prodigy probe head or on a Varian NMR system 400 operating at a frequency of .sup.1H: 500.36 MHz, .sup.31P: 202.56 MHz. .sup.31P NMR data were collected for the sake of clarity decoupled from proton: {1H}. The relaxation time D1 for .sup.31P NMR measurements was increased to 60 sec to determine the quantities of each P-species accordingly. MNova software was used to analyze the spectra.

[0184] For calculating M.sub.n of inventive oligomers, the signal of the end caps in the .sup.31P-NMR spectrum (quantitatively measured with a relaxation time D1=60 s) was set to 2. In consequence, the signals of the repeating units yield the number n of the repeating units. The number average molecular weight is calculated by adding the molecular weight of the termination groups, n x the molecular weight of the repeating unit and the molecular weight of the additional CH.sub.3).sub.2SiO.sub.2-unit.

[0185] For viscosity measurements an Anton Paar Physica MCR 51 was used. Measurements were conducted at 20° C. with shear stress profile from 10 to 1000 and averages were calculated.

[0186] Reaction yields were calculated based on the difference of the amount of starting materials, the released amount of alkyl chloride and the weight of obtained oligomer.

[0187] I.1 Overview of Starting Materials

##STR00013##

[0188] I.2 Synthesis of Inventive Oligomers and of Comparative Compounds

[0189] Comparative example 1: Dimethylphosphite (V.3)=1.4 mPa.Math.s

[0190] Comparative example 2: bis(trimethylsilyl)phosphite (C1), dynamic viscosity: 2.3 mPa.Math.s

[0191] Comparative example 3: tris(trimethylsilyl)phosphate (C2), dynamic viscosity: 4.3 mPa.Math.s

[0192] Inventive oligomer (I.1): dynamic viscosity: 170 mPa.Math.s

[0193] Inventive oligomer (I.4): dynamic viscosity: 12 mPa.Math.s

[0194] A summary of exemplified inventive oligomers is shown in Table 1.

[0195] Experiment 1—Inventive Oligomer (I.1):

[0196] A 250-ml three-necked flask with reflux condenser was charged with 88.0 g (1.0 eq, 800 mmol) dimethylphosphite (V.3). At room temperature, 104.8 g Me.sub.2SiCl.sub.2 ((VI.1), 1.0 eq, 800 mmol) were added, then heated under stirring to 90° C. and stirred for one hour until the formation of methyl chloride has ceased. The cooler temperature was 20° C. The flask with formed colorless residue was equipped with a distillation bridge and heated (1h, 100° C., 0.2 mbar) to yield inventive oligomer (I.1) with an average molecular weight M.sub.n of 957 g/mol as a colorless oil (105 g, 95% yield; chloride content 55 ppm).

[0197] Inventive oligomer (I.1) may be divided theoretically into different units: two P-containing termination groups [2×CH.sub.3OP(O)H—, together 158.03 g/mol], n Si- and P-containing repeating units [n×(CH.sub.3).sub.2SiO.sub.2P(O)H-unit, 138.14 g/mol per unit] and one additional (CH.sub.3).sub.2SiO.sub.2-unit (90.15 g/mol) according to the following structure:

##STR00014##

[0198] For calculating the number average molecular weight, the signal of the termination groups in the .sup.31P-NMR spectrum (quantitatively measured with a relaxation time D1=60 s) was set to 2 (signals with a chemical shift at −2.5 ppm). In consequence, the signals of the repeating units yield the number n of the repeating units (integral of signals with a chemical shift in the region from −14 to −17.5 ppm). The number average molecular weight is calculated by adding the molecular weight of the termination groups, n×the molecular weight of the repeating unit and the molecular weight of the additional CH.sub.3).sub.2SiO.sub.2-unit.

[0199] Dynamic Viscosity: 170 mPa.Math.s

[0200] Experiment 2—Inventive Oligomer (I.2):

[0201] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (0.9 eq, 765 mmol, 98.7 g), MeSiCl.sub.3 (0.1 eq, 85 mmol, 12.7 g) and dimethylphosphite (1.0 eq, 850 mmol, 93.5 g, (V.3)) were converted to yield inventive oligomer (1.2) (95.0 g, 87% yield). The chemical shifts for the termination and repeating unit in the .sup.31P NMR spectrum were in the same range as in experiment 1.

[0202] Dynamic viscosity: 180 mPa.Math.s

[0203] Experiment 3—Inventive Oligomer (I.3):

[0204] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (0.9 eq, 72 mmol, 9.47 g), SiCl.sub.4 (0.1 eq, 8 mmol, 1.4 g) and dimethylphosphite (1.0 eq, 80 mmol, 8.8 g, (V.3)) were converted to yield inventive oligomer (1.3). The chemical shifts for the termination and repeating unit in the .sup.31P NMR spectrum were in the same range as in experiment 1.

[0205] Experiment 4—Inventive Oligomer (I.4):

[0206] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (4.0 eq, 320 mmol, 4.30 g), and dimethylphosphite (1.0 eq, 80 mmol, 8.80 g, (V.3)) were converted to yield inventive oligomer (I.4) (5.00 g, 44% yield). The chemical shifts for the termination and repeating unit in the .sup.31P NMR spectrum were in the same range as in experiment 1.

[0207] Dynamic viscosity: 12 mPa.Math.s

[0208] Experiment 5—Inventive Oligomer (I.5):

[0209] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (1.0 eq, 70 mmol, 9.12 g) and dimethyl methylphosphonate (1.0 eq, 70 mmol, 8.95 g, (V.4)) were converted to yield inventive oligomer (1.5) (9.80 g, 92% yield). The chemical shift for the repeating unit was in the region from 8 to 12 ppm and the termination at 21 to 23 ppm in the .sup.31P NMR spectrum.

[0210] Experiment 6—Inventive Oligomer (I.6):

[0211] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (1.0 eq, 50 mmol, 6.45 g) and diethylphosphite (1.0 eq, 50 mmol, 7.12 g, (V.5)) were converted to yield inventive oligomer (1.6) (3.80 g, 53% yield). The chemical shift for the repeating unit was in the region from −14 to −17.5 ppm and the termination at −4.2 ppm in the .sup.31P NMR spectrum.

[0212] Experiment 7—Inventive Oligomer (I.7):

[0213] Following the conditions described in experiment 1, Me.sub.2SiCl.sub.2 (1.0 eq, 70 mmol, 9.17 g) and dimethyl phenylphosphonate (1.0 eq, 70 mmol, 13.30 g, (V.6)) were converted to yield inventive oligomer (I.7) (13.6 g, 88% yield). Inventive oligomer (I.7) had an average molecular weight Mn of 753 g/mol and a dynamic viscosity of 1520 mPa.Math.s. The chemical shift for the repeating unit was in the region from −0.2 to −2.5 ppm and the termination at 10.4 ppm in the .sup.31P NMR spectrum.

[0214] M.sub.n=753 g/mol was determined by .sup.31P NMR as discussed for experiment 1 except that the values for the termination groups [2.Math.CH.sub.3OP(O)H—, sum: 310.24 g/mol], n Si- and P-containing repeating units [n.Math.(CH.sub.3).sub.2SiO.sub.2P(O)H-unit, 214.25 g/mol per unit] and one additional (CH.sub.3).sub.2SiO.sub.2-unit (90.15 g/mol) according to the structure of I.7 were used.

[0215] Dynamic viscosity: 1520 mPa.Math.s

[0216] Experiment 8—Inventive Oligomer (I.8):

[0217] Following the conditions described in experiment 1, Et.sub.2SiCl.sub.2 (1.0 eq, 70 mmol, 7.86 g) and dimethylphosphite (1.0 eq, 70 mmol, 11.34 g, (V.3)) were converted to yield inventive oligomer (1.8) (15.3 g, 98% yield). The chemical shift for the repeating unit was in the region from −14 to −17.5 ppm and the termination at −4.2 ppm in the .sup.31P NMR spectrum.

[0218] Experiment 9

[0219] Following the conditions described in experiment 1, ClMe.sub.2SiOSiMe.sub.2Cl (1.0 eq, 80 mmol, 6.45 g) and dimethylphosphite (1.0 eq, 80 mmol, 9.00 g, (V.3)) were converted to yield inventive oligomer (I.9) (15.40 g, 87% yield). The chemical shift for the repeating unit was in the region from −15 to −17.5 ppm and the termination at −2.7 ppm in the .sup.31P NMR spectrum.

[0220] Inventive oligomers 1.2 to 1.9 were manufactured and analyzed as described in experiment 1 with the educts, ratios of educts and reaction conditions listed in Table 1. The composition of the mixtures obtained is also shown in Table 1.

TABLE-US-00001 TABLE 1 inventive oligomers Molar ratio of starting additional End-caps to Oligomer materials component [eq.] Conditions repeating units (I.1) 1:1 (V.3): Me.sub.2SiCl.sub.2 — 90° C., 60 min 27:73 (I.2) 1:0.9 (V.3): Me.sub.2SiCl.sub.2  0.1 (MeSiCl3) 90° C., 60 min 36:64 (I.3) 1:0.9 (V.3): Me.sub.2SiCl.sub.2  0.1 (SiCl.sub.4)  .sup.  90° C., 60 min 20:80 (I.4) 1:4 (V.3): Me.sub.2SiCl.sub.2 — 90° C., 60 min 88:12 (I.5) 1:1 (V.4): Me.sub.2SiCl.sub.2 — 90° C., 60 min 30:70 (I.6) 1:1 (V.5): Me.sub.2SiCl.sub.2 — 90° C., 60 min 82:18 (I.7) 1:1 (V.6): Me.sub.2SiCl.sub.2 — 90° C., 60 min 56:44 (1.8) 1:1 (V.3): Et.sub.2SiCl.sub.2  — 90° C., 60 min 91:9  (1.9)       1:1 (V.3): ClSiMe.sub.2OSiMe.sub.2Cl — 90° C., 60 min 19:81 Me: CH.sub.3, Et: CH.sub.2CH.sub.3

[0221] I.3 Studies on the Cooling Temperature Influence

[0222] Experiment 10:

[0223] In a trace-heated 250-mL stirred glass vessel equipped with 4-bladed pitched-blade turbine, an intense cooler (length 40 cm, 10° C.) regulated by a thermostat, thermometer for the reaction as well as for the off-gas control was added under inert atmosphere Me.sub.2SiCl.sub.2 (1.0 eq, 1 mol, 131.0 g) to dimethylphosphite (1.0 eq, 1 mol, 112.3 g, (V.3)) at 25° C. The colorless, clear mixture was stepwisely heated to 90° C. within 90 min and kept at this temperature for 30 min. The reaction mixture was cooled down to RT, the cooler was replaced by a distillation bridge and all volatiles were removed (90° C., 1 h, 0.5 mbar) to yield inventive oligomer I.10 as a clear oil (134.6 g, 97% yield; chloride content 15 ppm) with a dynamic viscosity of 243 mPa.Math.s. .sup.31P NMR analysis re-vealed a ratio of termination to repeating units of 21 to 79.

[0224] Experiment 11:

[0225] Following the conditions described in experiment 10 the cooling temperature was set to 25° C. instead of 10° C. to yield inventive oligomer I.11 (126.9 g, 91% yield) with a dynamic viscosity of 49 mPa.Math.s and a ratio of termination to repeating units of 44 to 56 based on .sup.31P NMR analysis.

[0226] Experiment 12:

[0227] Following the conditions described in experiment 13 the cooling temperature was set to −10° C. instead of +10° C. to yield inventive oligomer I.12 (135.6 g, 95% yield) with a dynamic viscosity of 590 mPa.Math.s and a ratio of termination to repeating units of 13 to 87 based on .sup.31P NMR analysis.

[0228] I.4 Manufacture of Inventive Cathode Active Materials

[0229] For wet-coating of cathode material with silyl-H-phosphonates, a Büchi glass oven for micro distillation, B-585 equipped with a rotation drying flask (30 mL) at 30 rpm (rounds per minute) was used.

[0230] Steps (a.1) and (a.2):

[0231] The following pristine cathode active materials were used:

[0232] 0.42Li.sub.2MnO.sub.3.Math.0.58Li(Ni.sub.0.4Co.sub.0.2Mn.sub.0.4)O.sub.2 (A.1). The overall formula was Li.sub.1.21(Ni.sub.0.23Co.sub.0.12Mn.sub.0.65).sub.0.79O.sub.2.06. D50: 9.62 μm, LASER diffraction in a Mastersize 3000 instrument from Malvern Instruments

[0233] Li.sub.1.03(Ni.sub.0.6Co.sub.0.2Mn.sub.0.2).sub.0.97O.sub.2(A.2). D50: 10.8 μm, LASER diffraction in a Mastersize 3000 instrument from Malvern Instruments.

[0234] Experiment I.4.1/Step (b.1):

[0235] The flask of the Büchi glass oven was charged with an amount of 25 g (A.1) under inert atmosphere. A solution of inventive oligomer (I.1) (0.25 g, 1 wt. %) in 40 mL dry dichloromethane was added and allowed to interact at 25° C. for 45 min. Then the Büchi glass oven was heated to 50° C. at reduced pressure (400 mbar and 30 rpm) to obtain a fine particulate solid after complete evaporation of the solvent and drying at 0.1 mbar for one hour. Inventive CAM.1 was obtained.

[0236] Experiment I.4.2/Step (b.2):

[0237] Experiment I.4.1 was repeated but with 40 mL of dried THF instead of dichloromethane. Inventive CAM.2 was obtained.

[0238] Experiment I.4.3/Step (b.3):

[0239] Experiment I.4.1 was repeated but with 40 mL of dried ethyl acetate instead of dichloromethane. Inventive CAM.3 was obtained.

[0240] Experiment I.4.4/Step (b.4):

[0241] Experiment I.4.1 was repeated but with 40 mL of dried acetone instead of dichloromethane. Inventive CAM.4 was obtained.

[0242] Experiment I.4.5/Step (b.5):

[0243] Experiment I.4.4 was repeated but with 0.125 g of inventive oligomer (I.2) instead of (I.1) (0.5 wt. %) was used. Inventive CAM.5 was obtained.

[0244] Experiment I.4.6/Step (b.6): Experiment I.4.4 was repeated but with 0.063 g of inventive oligomer (I.2) instead of (I.1) (0.25 wt. %) was used. Inventive CAM.6 was obtained.

[0245] Comparative experiment I.4.7/Step C-(b.7):

[0246] Experiment I.4.4 was repeated but without any inventive oligomer. C-CAM.7 was obtained.

[0247] Experiment I.4.8/Step (b.8):

[0248] The flask of the Büchi glass oven was charged an amount of 25 g (A.2) under inert atmosphere. A solution of inventive oligomer (1.2) (0.025 g, 0.1 wt. %) in 40 mL dry acetone was added and allowed to interact at 25° C. for 45 min. Then the Büchi glass oven was heated to 50° C. at reduced pressure (400 mbar) to obtain a fine particulate solid after complete evaporation of the solvent and drying at 0.1 mbar for one hour. Inventive CAM.8 was obtained.

[0249] Experiment I.4.9/Step (b.9):

[0250] Experiment I.4.4 was repeated but with 0.125 g of inventive oligomer (I.2) (0.5 wt. %) was used. Inventive CAM.9 was obtained.

[0251] Comparative Experiment I.4.10/Step C-(b.10):

[0252] Experiment I.4.8 was repeated but without any inventive oligomer. C-CAM.10 was obtained.

[0253] I.5 Dry-Coating Procedure

[0254] For an alternative way of treating cathode active material with inventive oligomer, a rotating and tilted mixing pan with an eccentrically arranged mixing tool—commercially available as Eirich laboratory mixer EL/5 equipped with a pin-type rotor—was used. Mixing speed was 300 rpm, inclination was 20°, the inert atmosphere was argon unless indicated otherwise.

[0255] Comparative Experiment I.5.1/Step C-(b.11)

[0256] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 417 g of cathode material powder (A.1). Mixing was started (300 rpm, at 25° C.) and immediately thereafter, 12.0 g dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. C-CAM.11 was obtained.

[0257] ICP measurements: P<0.03%; Si<0.03% (below detection level)

[0258] Experiment I.5.2/Step (b.12):

[0259] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 452 g of cathode active material (A.1). Mixing was started (300 rpm, at 25° C.) and immediately thereafter, 2.3 g inventive oligomer (I.2) (0.5 wt. %) in 10.4 g of dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. Inventive CAM.12 was obtained.

[0260] ICP measurements: P=0.11%; Si=0.07%

[0261] Experiment I.5.3/Step (b.13):

[0262] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 428 g of cathode active material (A.1). Mixing was started (300 rpm, at 25° C.) and immediately thereafter, 4.3 g of inventive oligomer (I.2) (1.0 wt. %) in 8.6 g of dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. Inventive CAM.13 was obtained.

[0263] ICP measurements: P=0.21%; Si=0.11%

[0264] Comparative Experiment I.5.4/Step C-(b.14)

[0265] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 496 g of cathode active material (A.2). Mixing was started (300 rpm, at 25° C.) and immediately thereafter, 20.7 g of dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. C-CAM.14 was obtained.

[0266] ICP measurements: P<0.03%; Si<0.03% (below detection level).

[0267] Experiment I.5.5/Step (b.15):

[0268] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 497 g of cathode active material (A.2). Mixing was started (300 rpm, at 25° C.) and immediately thereafter, 1.3 g of inventive oligomer (I.2) (0.25 wt. %) in 7.9 g of dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. Inventive CAM.15 was obtained.

[0269] ICP measurements: P=0.05%; Si=0.04%

[0270] Experiment I.5.6/Step (b.16):

[0271] Under inert atmosphere, the mixing chamber of the Erich laboratory mixer EL/5 was charged with 513 g of cathode active material (A.2). Mixing was started (300 rpm, at 25° C. and immediately thereafter, 2.6 g of inventive oligomer (I.2) (0.5 wt. %) in 5.2 g of dry acetone were added during 1 min, then mixing was resumed at 5000 rpm for 4 min. Inventive CAM.16 was obtained.

[0272] ICP measurements: P=0.11%; Si=0.07%

TABLE-US-00002 TABLE X1 Inventive cathode active materials employed Cathode Active Material Based upon Experiment No. (A.2) (Comparative Example) A.2 (Pristine) — CAM.1 (Inventive Example) A.1 I.4.1/Step (b.1) CAM.2 (Inventive Example) A.1 I.4.2/Step (b.2) CAM.3 (Inventive Example) A.1 I.4.3/Step (b.3) CAM.4 (Inventive Example) A.1 I.4.4/Step (b.4) CAM.5 (Inventive Example) A.1 I.4.5/Step (b.5) CAM.6 (Inventive Example) A.1 I.4.6/Step (b.6) C-CAM.7 (Comparative Example) A.1 I.4.7/Step (b.7) CAM.8 (Inventive Example) A.2 I.4.8/Step (b.8) CAM.9 (Inventive Example) A.2 l.4.9/Step (b.9) C-CAM.10 (Comparative Example) A.2 I.4.10/Step (b.10)

II. Manufacture of Inventive Cathodes

[0273] The positive electrodes for the electrochemical cycling experiments for the cathode active materials presented in Table X1 were prepared according based on the compositions presented in table X2. Such components, besides the cathode active material, are polyvinylidene fluoride (PVdF) binder, conductive additives such as active carbon (Super C65 L purchased form Timcal) and graphite (SFG6L from Timcal). The proportions into which these components are mixed are dependent on the cathode active material used and are presented in Table X2. Typically, all of the slurries were prepared on the basis of 20 g of cathode active material and the amount of NEP employed was such that the total solid content (CAM+SuperC65 L+SFG6L) was in the region from 59 to 62%. Additionally, in some selected cases, inventive oligomer (I.1) or (I.2) was added during the slurry preparation, see Table X2 in weight percent respect to the total amount of cathode active material present in the slurry. The components are mixed in the following order:

[0274] Step (c.1): In a planetary mixer (2000 rpm), a given amount of N-ethyl pyrrolidone (NEP), binder (PVdF) and inventive oligomer (I.1) or (I.2), if applicable, were added according to Table X2 and mixed in a for 3 minutes or until both components are fully dissolved. To the solution so obtained Super C65L and SFG6L were added according to Table X2 and mixed in a planetary mixer (2000 rpm) for 15 minutes or until a slurry with lump-free appearance was obtained. 20 g of CAM obtained according to I.4 were added. The resultant slurry was mixed again in a planetary mixer (2000 rpm) for 15 minutes or until a slurry with lump-free appearance was obtained.

[0275] Step (d.1): The slurry obtained from step (c.1) was applied to a 20 μm-thick aluminum foil with the help of a doctor blade. A loaded aluminum foil was thus obtained.

[0276] Step (e.1): The loaded aluminum foil from step (d.1) was dried under vacuum for 20 hours in a vacuum oven at 120° C. After cooling to room-temperature the electrodes were calendared and punched out in 14 mm-diameter disks. The resulting electrodes were then weighed, dried again at 120° C. under vacuum and introduced into an argon-filled glovebox.

[0277] Resultant inventive cathode tapes are summarized in Table X2.

TABLE-US-00003 TABLE X2 Proportion of the components employed for the preparation of cathode tapes PVdF Super Graphite oligomer Binder C65 SFG6 CAM Inventive concentration Cathode el (w. %) (w. %) (w. %) (w. %) CAM oligomer [%]* C-CT.1 3 1 2 94 A.2 — — CT.2 (Inventive) 3 1 2 94 A.2 (I.2) 0.1 CT.3 (Inventive) 3 1 2 94 A.2 (I.2) 0.5 CT.4 (Inventive) 3 1 2 94 CAM.8 — — CT.5 (Inventive) 3 1 2 94 CAM.9 — — C-CT.6 3.5 2 2 92.5 A.1 — — CT.7 (Inventive) 3.5 2 2 92.5 A.1 (I.1) 1 CT.8 (Inventive) 3.5 2 2 92.5 A.1 (I.2) 1 C-CT.9 3.5 2 2 92.5 A.1 (V.1) 1 C-CT.10 3.5 2 2 92.5 C-CAM.7 — — CT.11 (In- 3.5 2 2 92.5 CAM.1 — — ventive) CT.12 (In- 3.5 2 2 92.5 CAM.2 — — ventive) CT.13 (In- 3.5 2 2 92.5 CAM.3 — — ventive) CT.14 (In- 3.5 2 2 92.5 CAM.4 — — ventive) CT.15 (In- 3.5 2 2 92.5 CAM.5 — — ventive) CT.16 (In- 3.5 2 2 92.5 CAM.6 — — ventive) In comparative example 9, bis-trimethylsily phosphonate (V.1) was added *: % by weight referring to CAM

III. Manufacture of Full Coin Cells

[0278] The positive electrodes containing NCM-622 for the electrochemical cycling experiments, prepared as described above, and commercial graphite-coated tapes from Elexcel Corporation Ltd. were used as negative electrodes. The positive, negative composite electrodes, a polypropylene separator (Celgard) and the respective electrolyte were used to manufacture 2032 coin cells. All cells were assembled in an argon-filled glove box having oxygen and water levels below 1.0 ppm and their electrochemical testing carried out in a Maccor 4000 battery-test system.

[0279] For full coin cells C-CT.1 through CT.5 in Table X2, the electrolyte consisted of 1 M LiPF.sub.6 dissolved in a solvent mixture of ethylene carbonate and ethylmethyl carbonate mixed in a proportion of 50:50 in weight percent and additionally containing 2 wt. % vinylene carbonate.

[0280] For full coin cells C-CT.6 ff. in Table X2, the electrolyte consisted of 1 M LiPF.sub.6 in FEC:DEC:K2 (FEC=fluoroethylene carbonate, DEC=diethyl carbonate and K2=1H,1H,5H-perfluoropentyl-1,1,2,2-tetrafluoroethylether) mixed in proportion of 12:64:24 in volume percent.

IV. Evaluation of Inventive Electrochemical Cells

[0281] IV.1 Evaluation of cycling of Coin Cells based upon C-CT.1 through CT.5

[0282] IV.1 Formation at 25° C.

[0283] The respective coin full-cells were charged at a constant current of 0.1 C to a voltage of 4.2 V (CCCV charge, CV-step maximum duration of 30 minutes) and discharged at 0.1 C (2.7 V cut-off) (Cycle 1). Immediately after, the cells are charged at 25° C. at a constant current of 0.5 C to a voltage of 4.2 V (CCCV charge, CV-step maximum duration of 30 minutes) and discharged at 0.1 C (2.7 V cut-off) (Cycle 2). The charging procedure of cycle 2 was repeated 3 more times (Cycle 3-5). Then, the cells are charged at a constant current of 0.5 C to a voltage of 4.2 V, charged at 4.2 V for 30 minutes and, while keeping constant these charging conditions, then the cells are discharged to a discharge voltage of 2.7 V at a constant current of 1 C (2 times, cycles 6 to 7), 2 C (2 times, cycles 8 to 9) and 3 C (2 times, cycles 10 to 11). Finally, the cells are charged and discharged 11 times following the same procedure as that used in cycle 2.

[0284] IV.2 Evaluation of Cycling of Coin Cells at 25° C. and 4.35 V as Upper Cut-Off Voltage

[0285] Once the cells are formed they were charged at a constant current of 0.2 C to a voltage of 4.35 V and then discharged at a constant current of 0.1 C to a discharge voltage of 3.0 V. This procedure was repeated once (cycle 12 and 13). The charge capacity from cycle 13 was set as the reference discharge capacity value obtained at 0.2 C, corresponding to 100% (capacity check at 0.2 C procedure), and is further used as reference value for the subsequent cycle (cycle 14), in which the cells are charged sequentially in 25% SOC-steps at a constant current of 0.2 C. After each charging step, the cell resistance was determined by carrying out DC internal resistance (DCIR) measurements by applying a current interrupt. After reaching 100% SOC (4 charging 25% SOC-steps) the cells were discharged at 0.2 C to 3.0 V (Cell resistance determination procedure).

[0286] Following the first cell resistance measurements in cycle 14, the cells were charged at a constant current of 1 C to a voltage of 4.35 V, charged at 4.35 V until the current reached a value of 0.01 C or a maximum of 2 hours and discharged to a voltage of 3.0 V at a constant current of 1 C (Cycle 15). The discharge capacity measured in cycle 15 was set as the reference discharge capacity value obtained at 1 C and corresponding to 100%. This charge and discharge procedure was repeated 100 times. The discharge capacities after the resulting 100 cycles at 1 C and were expressed as a percentage of the reference discharge capacity measured in cycle 15 (1 C prolonged cycling procedure). Then, the procedures sequence composed of capacity check at 0.2 C, cell resistance determination and 1 C prolonged cycling was repeated a minimum of two times or until the cells reached capacities at 1 C below 70% of the reference value in cycle 15. The results after 300 cycles at 1 C from the various examples are presented in Table X3.

TABLE-US-00004 TABLE X3 Electrochemical data Remaining Capacity Remaining capacity Cell resistance at 1 C after at 0.2 C after increase after Cathode 300 Cycles 300 cycles 300 cycles C-CT.1 75.7% 77.8% 361% CT.2 81.2% 83.8% 253% (Inventive) CT.3 85.8% 86.5% 272% (Inventive) CT.4 87.0% 88.9% 261% (Inventive) CT.5 88.5% 88.0% 227% (Inventive)

[0287] IV.1.3 Evaluation of Cycling and Cell Resistance in Coin Full Cells at 25° C. based upon C-CT.6 through CT.16

[0288] The respective coin full cells were charged at a constant current of 0.067 C to a voltage of 4.7 V and discharged with a constant current of 0.067 C to a discharge voltage of 2.0 V (First activation cycle; cycle 1) at 25° C. Immediately after, the cells are charged at 25° C. at a constant current of 0.1 C to a voltage of 4.6 V. The cells were further charged at 4.6 V until the current reached a value of 0.05 C and then discharged at a constant current of 0.1 C to a discharge voltage of 2.0 V (cycle 2). The same procedure as in the second cycle was repeated once (cycle 3). The cells are then charged at a constant current of 0.1 C to a voltage of 4.6 V and then discharged at a constant current of 0.1 C to a discharge voltage of 2.0 V (cycle 4). The charge capacity from cycle 4 was set as the reference discharge capacity value obtained at 0.1 C, corresponding to 100% (capacity check at 0.1 C procedure). The charge capacity from this cycle was also used as reference value for the subsequent cycle (cycle 5), in which the cells were charged at a constant current of 0.1 C up to 40% of the charge capacity of cycle 5 (40% SOC). Once the cells reached 40% SOC, DC internal resistance (DCIR) measurements were carried out by applying a current interrupt (Cell resistance determination procedure).

[0289] In the cycles 6 to 7, the cells are charged at 25° C. at a constant current of 0.2 C to a voltage of 4.6 V. The cells were further charged at 4.6 V until the current reached a value of 0.05 C and then discharged at a constant current of 0.5 C to a discharge voltage of 2.0 V. Then, the cells are charged at a constant current of 0.7 C to a voltage of 4.6 V, charged at 4.6 V until the current reached a value of 0.05 C and, while keeping constant these charging conditions, the cells are discharged to a discharge voltage of 2.0 V at a constant current of 1 C (2 times, cycles 8 to 9), 2 C (2 times, cycles 10 to 11) and 3 C (2 times, cycles 12 to 13).

[0290] Following the variation of discharge rates, prolonged cycling was carried out by charging the cells at a constant current of 0.7 C to a voltage of 4.6 V, charging at 4.6 V until the current reached a value of 0.05 C and discharging to a discharge voltage of 2.0 V at a constant current of 1 C (Cycle 14). The discharge capacity measured for cycle 14 was recorded as the first discharge capacity at 1 C and set as the reference discharge capacity value obtained at 1 C and corresponding to 100%. This charge and discharge procedure was repeated at least 100 times or until the measured charge capacity is lower than 70% of the charge capacity of cycle 14. During the prolonged cycling experiments, capacity check at 0.1 C and DC internal resistance (DCIR) measurements at 40% SOC were carried out every 100 cycles. The latter was accomplished by repeating the cycling sequence described for cycles 2 to 5 every 100 1C-cycles. The results from the various examples are presented in Table X4.

TABLE-US-00005 TABLE X4 Electrochemical data Remaining Capacity Remaining Capacity Cell resistance at 1 C after at 0.1 after increase after Cathode 100 Cycles at 1 C 100 cycles at 1 C 100 Cycles at 1 C C-CT.6  <70% — — CT.7 89.5% 89.4% 120.3% CT.8 87.1% 84.0% 148.8% C-CT.9  <70% — — C-CT.10  <70% — — CT.11 87.6% 88.0% 135.0% CT.12 89.4% 90.5% 131.6% CT.13 92.8% 90.8% 171.1% CT.14 89.2% 87.6% 156.5%