POWDER OF SOLID MATERIAL PARTICLES OF FORMULA LiaPSbXc (I)

Abstract

The present disclosure relates to a powder of solid material particles of formula (I): Li.sub.aPS.sub.bX.sub.c whereinX represents at least one halogen element; a represents a number from 2.0 to 7.0; b represents a number from 3.0 to 6.0; and c represents a number from 0 to 3.0, wherein the powder has a d.sub.50-value of less than 50 m, characterised in that its L* value in the L*a*b* color system is less than 60.0. The present disclosure also relates to a process for preparing such powder, as well as to the use of such powder for notably manufacturing solid electrolytes or battery articles.

Claims

1. A powder of solid material particles of formula (I):
Li.sub.aPS.sub.bX.sub.c(I) wherein X represents at least one halogen element; a represents a number from 2.0 to 7.0; b represents a number from 3.0 to 6.0; and c represents a number from 0 to 3.0, wherein the powder has a d.sub.50-value in the range from 2 m to less than 70 m, as determined by laser diffraction using para-xylene, characterized in that its L* value in the L*a*b* color system is less than 60.0.

2. The powder of claim 1, wherein the solid material is according to formula (II):
Li.sub.7-xPS.sub.6-xX.sub.x(II) wherein: X represents at least one halogen element selected in the group of F, Cl, Br and I or a combination thereof; and x represents a positive number from 0.5 to 2.0.

3. The powder of claim 1, wherein the solid material is Li.sub.6PS.sub.5Cl, Li.sub.4P.sub.2S.sub.6, Li.sub.7PS.sub.6, Li.sub.7P.sub.3S.sub.11 or Li.sub.3PS.sub.4.

4. The powder of claim 1, presenting: a d.sub.50-value of less than 50 m, a d.sub.10-value higher than 0.05 m, and/or a d.sub.90-value of less than 100 m, as measured by laser diffraction in para-xylene.

5. The powder of claim 1, presenting an ionic conductivity of at least 1.5 mS/cm, as measured on pressed (500 MPa) pellets by impedance spectroscopy.

6. The powder of claim 1, wherein the powder is obtained by a process involving wet mechanochemistry with a carbonated solvent.

7. The powder of claim 6, wherein the process comprises the steps of: a) mixing the starting materials (M) with a carbonated solvent(S) using mixing means with an energy of at least 710.sup.5 rotations per litre of mixture (M+S), to obtain a paste in a slurry state, b) drying the paste from step a) to obtain a dried paste, b) optionally pressing the dried paste from step b) into pellets; and c) heating the dried paste, e.g. in the form of pellets, to a temperature between 350 C. and 580 C. for a time period of at least 2 hours.

8. The powder of claim 7, wherein the starting materials (M) are at least lithium sulfide (Li.sub.2S) and phosphorus sulfide.

9. The powder of any one of claim 6, wherein the solvent is selected from the group consisting of p-xylene, heptane, octane, and mixture thereof.

10. A process for manufacturing a powder of solid material particles of formula (I):
Li.sub.aPS.sub.bX.sub.c(I) wherein X represents at least one halogen element; a represents a number from 2.0 to 7.0; b represents a number from 3.5 to 6.0; and c represents a number from 0 to 3.0, wherein the powder has a d.sub.50-value of less than 50 m, characterised in that its L* value in the L*a*b* color system is less than 60.0, the process comprising the steps of: a) mixing the starting materials (M) with a carbonated solvent(S) using mixing means with an energy of at least 7.010.sup.5 rotations per litre of mixture (M+S), to obtain a paste in a slurry state, b) drying the paste from step a) to obtain a dried paste, b) optionally pressing the dried paste from step b) into pellets; and c) heating the dried paste, e.g. in the form of pellets, to a temperature between 350 C. and 580 C. for a time period of at least 2 hours.

11. (canceled)

12. A solid electrolyte comprising at least the powder of claim 1.

13. A solid state battery comprising at least the solid electrolyte of claim 12.

14. An electrode comprising at least: a metal substrate; directly adhered onto said metal substrate, at least one layer made of a composition comprising: (i) the powder of claim 1; (ii) at least one electro-active compound (EAC); (iii) optionally at least one lithium ion-conducting material (LiCM) other than the solid material of the invention; (iv) optionally at least one electro-conductive material (ECM); (v) optionally a lithium salt (LIS); and (vi) optionally at least one polymeric binding material (P).

15. A separator comprising at least: the powder of claim 1; optionally at least one polymeric binding material (P); optionally at least one metal salt, notably a lithium salt; and optionally at least one plasticizer.

Description

EXAMPLES

[0125] The disclosure will be now described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the disclosure.

Materials

Inventive Material #1

[0126] Inventive materials Li.sub.6PS.sub.5Cl are obtained with a process as follows.

[0127] In a first step, 15.8 g of LiCl (Sigma-Aldrich, purity>99%); 41.4 g of P.sub.2S.sub.5 (Sigma-Aldrich, purity>99%) and 42.5 g of Li.sub.2S (Sigma-Aldrich) were added into a 500 mL zirconia jar with ZrO.sub.2 balls (10 mm). 100.5 g of para-xylene (Sigma-Aldrich, purity>99%, dry) were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. The milling was performed for 21 h at 500 rpm, which corresponds to an energy of approx. 3.810.sup.6 rotations per litre of mixture of the starting materials and the solvent. A slurry paste is obtained.

[0128] In a second step, the paste was transferred in a dry alumina crucible and dried under dynamic vacuum at 130 C. in an oven to remove the solvent. After 5 hours of drying, the milling balls were separated from the dried powder through sieving at 4 mm.

[0129] In a third step, the dried mixture was charged under argon atmosphere (with less than 10 ppm of water) in an alumina crucible. The crucible was then inserted in a tubular furnace and the product was crystallised at a temperature higher than 400 C. during 12 hours under N.sub.2 flow (20 L/h). The oven was then cooled down before the crucible was collected.

[0130] The final product was in the form of a polydisperse powder with some agglomerates of different sizes. The finished product was obtained by dry homogenization.

Inventive Material #2

[0131] In a first step, 19.7 g of LiCl (Sigma-Aldrich, purity>99%); 51.7 g of P.sub.2S.sub.5 (Sigma-Aldrich, purity>99%) and 53.4 g of Li.sub.2S (Sigma-Aldrich) were added into a zirconia jar with ZrO.sub.2 balls (10 mm). 125 g of para-xylene (Sigma-Aldrich, purity>99%, dry) were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. The milling was performed for 65 h at 290 rpm. The energy spent to prepare the slurry paste was approx. 6.810.sup.6 rotations per litre of mixture of the starting materials and the solvent.

[0132] In a second step, the paste was transferred in a dry alumina crucible and dried under dynamic vacuum at 130 C. in an oven to remove the solvent. After 5 hours of drying, the milling balls were separated from the dried powder through sieving at 4 mm.

[0133] In a third step, the dried mixture was charged under argon atmosphere (with less than 10 ppm of water) in an alumina crucible. The crucible was then inserted in a tubular furnace and the product was crystallised at a temperature higher than 400 C. during 12 hours under N.sub.2 flow (20 L/h). The oven was then cooled down before the crucible was collected.

[0134] The final product was in the form of a polydisperse powder with some agglomerates of different sizes. The finished product was obtained by dry homogenization.

Inventive Material #3

[0135] In a first step, 16.2 g of LiCl; 52.9 g of P.sub.2S.sub.5, 33.1 g of LiBr and 41.6 g of Li.sub.2S were added into a zirconia jar with ZrO.sub.2 balls (10 mm). 129.4 g of xylene were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. The milling was performed for 15 h at 350 rpm. The energy spent to prepare the slurry paste was approx. 1.910.sup.6 rotations per litre of mixture of the starting materials and the solvent.

[0136] In a second step, the paste was transferred in a dry round bottom flask and dried under dynamic vacuum at 60 C. in a rotative evaporator to remove the solvent. After 3 hours of drying, the milling balls were separated from the dried powder through sieving at 4 mm.

[0137] In a third step, the dried mixture was charged under argon atmosphere (with less than 10 ppm of water) in an alumina crucible. The crucible was then inserted in a tubular furnace and the product was crystallised at 500 C. during 6 hours under N.sub.2 flow (20 L/h). The oven was then cooled down before the crucible was collected.

[0138] The final product was in the form of a polydisperse powder with some agglomerates of different sizes. The finished product was obtained by dry homogenization.

Inventive Material #4

[0139] In the first step, 14.7 g of LiCl; 25.7 g of P.sub.2S.sub.5 and 21.2 g of Li.sub.2S were added into a zirconia jar with ZrO.sub.2 balls (10 mm). 123 g of xylene were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. The milling was performed for 15 h at 350 rpm. The energy spent to prepare the slurry paste was approx. 1.910.sup.6 rotations per litre of mixture of the starting materials and the solvent.

[0140] In a second step, the paste was transferred in a dry round bottom flask and dried under dynamic vacuum at 60 C. in a rotative evaporator to remove the solvent. After 3 hours of drying, the milling balls were separated from the dried powder through sieving at 4 mm.

[0141] In a third step, the dried mixture was charged under argon atmosphere (with less than 10 ppm of water) in a dry silicon carbide crucible coated with a papyex sheet. The crucible was then inserted in a tubular furnace and the product is crystallised at 520 C. during 12 hours under N.sub.2 flow (20 L/h). The oven was then cooled down before the crucible was collected.

[0142] The final product was in the form of a polydisperse powder with some agglomerates of different sizes. The finished product was obtained by dry homogenization.

Inventive Material #5

[0143] In a first step, 6.2 g of LiCl; 16.3 g of P.sub.2S.sub.5 and 16.8 g of Li.sub.2S were added into a zirconia jar with ZrO.sub.2 balls (10 mm). 91 g of xylene were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. The milling was performed for 8 h at 300 rpm. The energy spent to prepare the slurry paste was approx. 8.610.sup.5 rotations per litre of mixture of the starting materials and the solvent.

[0144] In a second step, the paste was transferred in a dry round bottom flask and dried under dynamic vacuum at 60 C. in a rotative evaporator to remove the solvent. After 3 hours of drying, the milling balls were separated from the dried powder through sieving at 4 mm.

[0145] In a third step, the dried mixture was charged under argon atmosphere (with less than 10 ppm of water) in an alumina crucible. The crucible was then inserted in a tubular furnace and the product was crystallized at 510 C. during 6 hours under N.sub.2 flow (20 L/h). The oven was then cooled down before the crucible was collected.

[0146] The final product was in the form of a polydisperse powder with some agglomerates of different sizes. The finished product was obtained by dry homogenization.

Comparative Material #A

[0147] In a first step, 22.7 g of LiCl (Sigma-Aldrich, purity>99%); 59.5 g of P.sub.2S.sub.5 (Sigma-Aldrich, 20 purity>99%) and 61.5 g of Li.sub.2S were added into a zirconia jar with ZrO.sub.2 balls (10 mm). 130 g of para-xylene (Sigma-Aldrich, purity>99%, dry) were then added. The tight jar was rapidly sealed to prevent any solvent evaporation. Wet-ball milling was conducted with a planetary ball-mill. After 7 h of milling at 200 rpm, which corresponds to 510.sup.5 rotations per litre of mixture (the rotation being smaller than 710.sup.5 rotations per litre), a slurry paste was obtained.

[0148] Such a material had an L* value in the L*a*b* color system which was above 60.0 and not suitable to be used as a material for a solid state battery with the expected performance properties.

Comparative Material #B

[0149] Standard material Li.sub.6PS.sub.5Cl was obtained with the following process.

[0150] In a first step, 0.631 g of LiCl (purity>99%); 1.655 g of P.sub.2S.sub.5 (purity>99%) and 1.713 g of Li.sub.2S (purity>99%) are added into a 45 mL zirconia jar with 5 mm ZrO.sub.2 balls. Ball milling was conducted with a planetary ball-mill. After 2 hours of milling at 500 rpm, a mixed powder was obtained.

[0151] In a second step, the powder was homogenised in a mortar inside an Ar filled glovebox (<1 ppm H.sub.2O, <1 ppm O2) and then pelletized under 500 MPa to make 6 mm diameter pellets with a mass ranging from 300 to 500 mg. These pellets were sealed under vacuum in carbon covered quartz tubes. The products were crystallised at 550 C. for 7 h with a heating and cooling ramp of 0.5 C./min.

[0152] The final product was in the form of densified pellets. The finished product was obtained by dry homogenization with a mortar in the Ar filled glovebox.

Test Methods

L* Value in the L*a*b* Color System

[0153] The L value is measured with a X-Rite Ci52 spectrophotometer operated by the software OnColor. The apparatus is calibrated with to a white standard (L*a*b=95.82-0.60 2.15) and a black trap before any measurement is carried out on a sulfide. A thin layer of powder to be analysed is put in a sample holder with a quartz window to guarantee the stability of the sample during the measurement.

PSD

[0154] The PSD of the dispersion is measured by laser diffraction using para-xylene in a Malvern Mastersizer 3000.

Conductivity & Electrochemical Impedance Spectroscopy (EIS)

[0155] Before the impedance spectroscopy measurements, powder samples were cold-pressed at 500 MPa in an Ar filled glovebox. The conductivity was acquired on pellets done using a uniaxial press operated at 500 MPa.

[0156] Pelletizing was done using a lab scale uniaxial press in glovebox filled with moisture free Argon atmosphere. Two carbon paper foils (Papyex soft graphite N998 Ref: 496300120050000, 0.2 mm thick from Mersen) are used as current collector. Pellets with their carbon electrodes attached are then loaded into air-tight sample holders and a pressure of 40 MPa is applied on the sample holder for the measurement. The impedance spectra are acquired on a Biologic VMP3 device. The samples are placed in a Binder thermostatic chamber to perform the impedance measurements at different temperatures. Each spectrum is acquired after 2 hours of stabilization at the target temperature. The temperature range goes from 20 C. to 60 C. by steps of 10 C. Impedance spectroscopy is acquired in PEIS mode with an amplitude of 20 mV and a range of frequencies from 1 MHz to 1 kHz (25 points per decade and a mean of 50 measurements per frequency point).

Results

PSD Results

Inventive Material #1

[0157] d.sub.10-value=27 m [0158] d.sub.50-value=61 m [0159] d.sub.90-value=107 m

Inventive Material #2

[0160] d.sub.10-value=4 m [0161] d.sub.50-value=16 m [0162] d.sub.90-value=43 m

Inventive Material #3

[0163] d.sub.10-value=7 m [0164] d.sub.50-value=26 m [0165] d.sub.90-value=62 m

Inventive Material #4

[0166] d.sub.10-value=8 m [0167] d.sub.50-value=22 m [0168] d.sub.90-value=50 m

Inventive Material #5

[0169] d.sub.10-value=3 m [0170] d.sub.50-value=10 m [0171] d.sub.90-value=48 m

Comparative Material #B

[0172] d.sub.10-value=7 m [0173] d.sub.50-value=27 m [0174] d.sub.90-value=103 m

TABLE-US-00001 Comparative Inventive material material #1 #2 #3 #4 #5 #B L* value 46.9 52.5 58.0 50.0 54.3 71.0 i 1.45 2.20 9.40 7.00 7.00 3.50 (mS/cm) at 30 C. C-content 1.6% 1.1% 0.21% 0.37% 2.8% Not measured