Anode for a lithium-ion battery cell, production method thereof and battery including same

Patent metadata

Field	Value
Publication number	US-2019165366-A1
Application number	US-201716320603-A
Country	US
Kind code	A1
Filing date	Jul 21, 2017
Priority date	Jul 26, 2016
Publication date	May 30, 2019
Grant date	—

Abstract

Polymer composition for an electrode, method, and a lithium-ion battery including same are provided. This composition includes an active material having a graphite usable in the anode, an electrically conductive filler and a cross-linked elastomer binder that includes a hydrogenated acrylonitrile butadiene copolymer (HNBR). The binder includes a non-hydrogenated acrylonitrile butadiene copolymer (NBR) and/or an HNBR with an acrylonitrile content that is at least 40% by weight and cross-linked by thermal oxidation. This method includes: a) mixing the active material, the binder in a non-cross-linked state and the electrically conductive filler, to obtain a precursor mixture of the composition, b) depositing the mixture on a metal current collector so that the mixture forms a non-cross-linked film, then c) thermal oxidation of the non-cross-linked film under an atmosphere containing oxygen at a temperature of between 200 and 300° C., to obtain the electrode in which the binder is cross-linked.

First claim

1 . A polymeric composition for an electrode that is capable of forming a lithium-ion battery anode, the composition comprising an active material which comprises a graphite that is capable of performing reversible insertion/deinsertion of lithium at said anode, an electrically conductive filler and a crosslinked elastomeric binder which comprises at least one hydrogenated acrylonitrile-butadiene copolymer (HNBR), characterized in that said crosslinked binder comprises at least one non-hydrogenated acrylonitrile-butadiene copolymer (NBR) and/or at least one said hydrogenated acrylonitrile-butadiene copolymer (HNBR) which each have a mass content of acrylonitrile-based units of greater than or equal to 40% and which is (are) crosslinked via thermal oxidation.

2 . The composition as claimed in claim 1 , wherein said crosslinked binder comprises the product of a thermal oxidation chemical reaction, under an atmosphere comprising oxygen at a partial pressure of oxygen of greater than 10 4 Pa and at a temperature of between 200° C. and 300° C., of said at least one NBR and/or of said at least one HNBR in non-crosslinked form, of said active material and of said electrically conductive filler with the oxygen of said atmosphere.

3 . The composition as claimed in claim 1 , wherein said acrylonitrile-based units borne by said at least one NBR and/or said at least one HNBR which is (are) crosslinked are at least partially enriched in oxygen atoms and depleted in hydrogen atoms by said thermal oxidation.

4 . The composition as claimed in claim 1 , characterized in that the composition is free of any system for crosslinking said at least one NBR and/or said at least one HNBR which is (are) crosslinked, such as.

5 . The composition as claimed in claim 1 , wherein said crosslinked binder comprises a mass fraction inclusively between 70% and 100% of said at least one NBR and/or of said at least one HNBR, said crosslinked binder being present in the composition in a mass fraction of less than 5%.

6 . The composition as claimed in claim 1 , wherein said crosslinked binder comprises at least one HNBR which has an iodine number, measured according to the standard ASTM D5902-05, of greater than 10%.

7 . The composition as claimed in claim 1 , wherein said crosslinked binder comprises a mixture of said at least one NBR and of said at least one HNBR.

8 . The composition as claimed in claim 1 , wherein said mass content of acrylonitrile-based units is greater than or equal to 44%.

9 . The composition as claimed in claim 1 , wherein the composition comprises:
in a mass fraction of greater than 90%, said active material comprising said graphite which is of artificial type, and in a mass fraction of between 1% and 6%, said electrically conductive filler which is chosen from the group constituted by carbon blacks, graphites, expanded graphites, carbon fibers, carbon nanotubes, graphenes, and mixtures thereof.

10 . An electrode which is capable of forming a lithium-ion battery anode, wherein the electrode comprises at least one film constituted of a composition as claimed in claim 1 , and a metal current collector in contact with said at least one film.

11 . A lithium-ion battery comprising at least one cell including an anode, a cathode and an electrolyte based on a lithium salt and a nonaqueous solvent, wherein said anode is constituted of an electrode as claimed in claim 10 .

12 . A process for preparing a composition as claimed in claim 1 , characterized in that the process successively comprises:
a) mixing of ingredients of the composition comprising said active material, said elastomeric binder in non-crosslinked form and said electrically conductive filler, to obtain a precursor mixture of said composition, b) deposition of said mixture on a metal current collector so that said mixture forms a non-crosslinked film, and then c) thermal oxidation of said non-crosslinked film under an atmosphere comprising oxygen at a partial pressure of oxygen of greater than 10 4 Pa and at a temperature of between 200° C. and 300° C., to obtain said electrode in which said binder is crosslinked.

13 . The process as claimed in claim 12 , characterized in that the following are performed:
step a) by liquid-route grinding of said ingredients dissolved or dispersed in a solvent, and step c), after evaporation of said solvent following step b), by annealing said film.

14 . The process as claimed in claim 12 , characterized in that the following are performed:
step a) by melt-route mixing of said ingredients and without evaporation of solvent, said ingredients also comprising a sacrificial polymeric phase in a mass fraction in said mixture of greater than or equal to 28%, and step c) by thermal decomposition of said sacrificial polymeric phase having a thermal decomposition temperature which is at least 20° C. below that of said binder, to at least partially remove said sacrificial polymeric phase.

15 . The process as claimed in claim 14 , wherein said sacrificial polymeric phase comprises at least one sacrificial polymer chosen from polyalkene carbonates and is present in said mixture in a mass fraction of between 30% and 50%, and in that step a) is performed in an internal mixer or an extruder without macro-phase separation between said binder and said sacrificial polymeric phase in said mixture, in which said binder is homogeneously dispersed in said sacrificial polymeric phase which is continuous or forms a co-continuous phase with said phase.

16 . The composition as claimed in claim 5 , wherein said crosslinked binder is present in the composition in a mass fraction of less than or equal to 4%.

17 . The composition as claimed in claim 6 , wherein said crosslinked binder comprises said at least one HNBR which has an iodine number, measured according to the standard ASTM D5902-05, of greater than 15%.

18 . The composition as claimed in claim 8 , wherein said mass content of acrylonitrile-based units is greater than or equal to 48%.

Assignees

• Hutchinson

Inventors

• Sonntag Philippe
• Courtat Julie
• Zimmermann Marc
• Astafyeva Ksenia
• Dufour Bruno
• Ayme-Perrot David

Classifications

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/622 Primary

  being polymers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title