Electrode for Energy Storage Device

Abstract

An electrode for an electrochemical energy storage device formed from an electrostatic deposition process employs a composite particle including active material (AM) particle with adhered binder and optionally conductive particles formed with sufficient interaction forces between the individual ingredient particles to form an effective composite particle which can overcome particle separation during electrostatic charging, fluidization, and/or mechanical conveyance. Secondary binder particles undergo deagglomeration to form sub particles, which are adhered to the AM particles having a predetermined morphology. Smaller conductive particles, typically carbon black (CB) or similar carbon, are bound to the binder and adhere to the AM particles. The result is a composite particle adhered for withstanding separation forces imposed from electrostatic deposition onto a current collector. Application of a plurality of composite particles onto a conductive current collector in a uniform pattern and defined loading promotes robust energy density, power density, and cycle life for an electrochemical energy storage device.

1 . An electrode, comprising:
 a conductive current collector substrate;   one or more electrostatic deposited coating layers deposited on the conductive current collector substrate and adhered relative to the conductive current collector substrate;   wherein the one or more electrostatic deposited coating layers includes a plurality of dry mixed composite particles, each dry composite particle of the plurality of dry mixed composite particles including (i) one or more active material particles, and (ii) deagglomerated binder particles surrounding each of the one or more active material particles; and   wherein the deagglomerated binder particles adhere relative to a surface of an active material particle from among the one or more active material particles through interactions that are sufficient to withstand mixing associated with formation of the dry composite particles and to overcome separation forces induced from the depositing of the one or more electrostatic deposited coating layers on the conductive current collector substrate;   thereby maintaining a structure of the composite particle when applied onto the conductive current collector substrate.   
     
     
         2 . The electrode of  claim 1 , wherein the one or more active material particles function as a cathode material. 
     
     
         3 . The electrode of  claim 2 , wherein the one or more active material particles are selected from (i) lithium transition metal oxides, lithium transition metal sulfides, lithium polyanion cathode materials, including lithium transition metal phosphates, lithium transition metal silicates or their combinations or from (ii) sodium transition metal oxide, sodium polyanion cathode material, Prussian Blue Analogues cathode materials, or their combinations. 
     
     
         4 . The electrode of  claim 1 , wherein the one or more active material particles function as an anode material. 
     
     
         5 . The electrode of  claim 4 , wherein the one or more active material particles are selected from (i) carbonaceous anode materials, graphite, Si, Si-based composites, SiOx, lithium alloyable materials, or lithium transition metal oxide anode materials or their combinations, or from (ii) sodium alloyable materials or ion intercalation anode materials, including Prussian Blue Analogues anodes, and sodium metal transition metal oxide anodes. 
     
     
         6 . The electrode of  claim 1 , wherein the structure is incorporated into an assembly selected from the group consisting of a rechargeable lithium battery, a Li-ion battery, a rechargeable lithium sulfur battery, a solid state battery, a rechargeable sodium battery, and a sodium-ion battery. 
     
     
         7 . The electrode of  claim 1 , wherein the deagglomerated binder particles are formed from one or more of polymeric materials, polymer electrolytes and solid state electrolyte composites. 
     
     
         8 . The electrode of  claim 7 , wherein the polymeric materials are selected from polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, poly(methyl methacrylate), polystyrene butadiene rubber binder, carboxymethyl cellulose binder, polyacrylic acid or a combination thereof. 
     
     
         9 . The electrode of  claim 1 , wherein the dry mixed composite particles further comprise conductive particles adhered to a surface of at least one of the one or more active material particles and the deagglomerated binder particles. 
     
     
         10 . The electrode of  claim 9 , wherein the conductive particles are selected from the group consisting of carbon black, carbon nanotube, carbon fiber, graphene, graphite, or a combination thereof. 
     
     
         11 . The electrode of  claim 1 , wherein the conductive current collector substrate is selected from an Al or Cu foil. 
     
     
         12 . The electrode of  claim 11 , further comprising a prime layer to enhance adhesion between the one or more electrostatic deposited coating layers and the conductive current collector substrate. 
     
     
         13 . The electrode of  claim 1 , wherein a size of the deagglomerated binder particles is between 0.1%-70% of an average size of the one or more active material particles. 
     
     
         14 . The electrode of  claim 1 , wherein an average size of the one or more active material particles is greater than 5 μm, and an average size of the deagglomerated binder particles is less than 10% of the average size of the one or more active material particles. 
     
     
         15 . The electrode of  claim 1 , wherein an average size of the one or more active material particles is less than 5 μm, and an average size of the deagglomerated binder particles is less than 70% of the average size of the one or more active material particles. 
     
     
         16 . The electrode of  claim 1 , wherein the dry mixed composite particles further comprise conductive particles, and wherein greater than 50% of the deagglomerated binder particles and the conductive particles are adhered relative to an active material particle from among the one or more active material particles. 
     
     
         17 . A method for forming an electrode, comprising:
 combining one or more active material particles and deagglomerated binder particles to form a plurality of dry mixed composite particles wherein the deagglomerated binder particles surround each of the one or more active material particles;   adhering the plurality of dry mixed composite particles relative to a surface of a conductive substrate by an electrostatic deposition process.   
     
     
         18 . The method of  claim 17 , further comprising:
 deagglomerating an agglomeration of binder material to form the deagglomerated binder particles.   
     
     
         19 . The method of  claim 17 , further comprising:
 combining conductive particles with the one or more active material particles and deagglomerated binder particles, wherein the conductive particles adhere relative to a surface of the deagglomerated binder particles, and   subsequently forming the composite particles by adhering the combined binder and conductive particles to a surface of the one or more active material particles.   
     
     
         20 . The method of  claim 17 , wherein the electrostatic deposition process is selected from the group consisting of corona-charging electrostatic deposition, tribo-charging electrostatic deposition and direct electrode induction charging deposition. 
     
     
         21 . The method of  claim 17 , wherein the deagglomerated binder particles are formed from binder material by combining the one or more active material particles and the binder material and agitating a dry mixture thereof to overcome agglomeration forces and form the deagglomerated binder particles from the binder material; thereby adhering the deagglomerated binder particles to a surface of the one or more active material particles to form composite particles having interaction forces between the deagglomerated binder particles and the one or more active material particles sufficient to maintain adherence during electrostatic charging, fluidization and mechanical conveyance. 
     
     
         22 . The method of  claim 21 , wherein the agitation imparts sufficient force to pulverize the dry mixture. 
     
     
         23 . The method of  claim 21 , wherein adherence of the plurality of dry mixed composite particles relative to the surface of the conductive substrate comprises depositing the plurality of composite particles onto the conductive substrate for forming a coating layer having predetermined active material loading; and
 further comprising densifying the coating layer and conductive substrate through a densification process selected from the group consisting of (i) pre-heating the coating layer and conductive substrate prior to the densification process, (ii) pre-heating the coating layer and conductive substrate prior to densification under heating, and (iii) densification of the coating layer and conductive substrate under heating.   
     
     
         24 . The method of  claim 23 , wherein the densification process is undertaken repeatedly. 
     
     
         25 . The method of  claim 21 , wherein the agitation results in deagglomerated binder particles sized between 200-1000 nm. 
     
     
         26 . The method of  claim 17 , wherein the combining step includes combining conductive particles with the one or more active material particles and the deagglomerated binder particles to form the plurality of dry mixed composite particles, whereby the conductive particles adhere relative to the deagglomerated binder particles. 
     
     
         27 . The method of  claim 17 , wherein the deagglomerated binder particles are formed from binder material by combining the one or more active material particles and the binder material and agitating a dry mixture thereof to overcome agglomeration forces and form the deagglomerated binder particles from the binder material;
 wherein a structure of the one or more active particles is maintained during the agitation and adherence relative to the surface of the conductive substrate;   wherein the deagglomerated binder particles are formed by dissociating agglomerates of binder materials; and   wherein combination of the one or more active material particles and the deagglomerated binder particles to form the plurality of dry mixed composite particles comprises agitating the one or more active material particles and deagglomerated binder particles in a solventless manner for adhering the deagglomerated binder particles and maintaining morphology of the one or more active material particles during agitation.   
     
     
         28 . The method of  claim 17 , wherein further comprising:
 combining the deagglomerated binder particles with conductive particles so as to adhere the conductive particles relative to the deagglomerated binder particles; and   adhering the combined deagglomerated binder particles and conductive particles to a surface of one of the one or more active material particles to form the dry mixed composite particles,   wherein the dry mixed composite particles have less than 20% by weight of a total of conductive particles and deagglomerated binder particles;   wherein an average size of the binder particle is less than 50% of a mean active material particle size; and   wherein an average size of the conductive particle is less than 30% of the average size of the deagglomerated binder particle.   
     
     
         29 . The method of  claim 17 , further comprising forming an electrode from the conductive substrate with adhered dry mixed composite particles. 
     
     
         30 . The method of  claim 17 , further comprising including the conductive substrate with adhered dry mixed composite particles in a battery.