Solid CO2 Lithium Carbonate Coating for Cathode Stability

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Solution Overview

Problem

Lithium-ion cathode materials face instability in aqueous-based electrode manufacturing due to lithium ion dissolution, leading to ionic barriers and pH-related damage, which hampers electrophoretic deposition and increases production time and costs.

Innovation Solution

A solid-state method using solid carbon dioxide to convert surface impurities on cathode particles into lithium carbonate coatings, eliminating the need for solvents, reducing reaction time, and maintaining a stable pH environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aqueous-based electrode manufacturing is used, then manufacturing cost and production time are reduced, but cathode particles become unstable due to lithium ion dissolution

Engineering Contradiction:

Improveproduction timeVSAvoidcathode particle stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary substance (water-soluble polymer coating) that mediates between the aqueous manufacturing environment and the cathode particles. This coating layer allows the particles to be processed in water-based slurries without direct harmful interaction between water and the cathode material, thus maintaining particle stability while enabling aqueous manufacturing processes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a disposable protective coating layer on cathode particles that can be applied quickly and removed or degraded after serving its protective function during manufacturing. This allows rapid processing in aqueous environments without requiring long-term particle stability modifications

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If lithium carbonate coating is applied to protect cathode particles, then water stability is improved, but production time increases significantly

Engineering Contradiction:

Improvewater stabilityVSAvoidproduction time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the chemical parameters of the coating process by using water-soluble polymers that can be applied and cured under milder, faster conditions compared to traditional lithium carbonate formation processes. This allows achieving protective coating in significantly reduced time while maintaining water stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary protective coating to cathode particles before they undergo aqueous processing or assembly. This preliminary action prevents water-related damage from the outset, eliminating the need for lengthy post-processing stabilization steps

Inventive Principle:

Principle #10Preliminary action

3Productivity

If electrophoretic deposition is used to manufacture electrodes, then manufacturing efficiency is improved, but dissolved lithium ions create ionic barriers that reduce deposition efficiency

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidionic barriers

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts or removes dissolved lithium ions from the aqueous slurry through filtration, dialysis, or other separation techniques before the electrophoretic deposition process. This eliminates the ionic barriers that would otherwise interfere with the electrophoresis, allowing efficient electrode manufacturing while maintaining the benefits of aqueous processing

Inventive Principle:

Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enhances the water stability of cathode particles, reduces production time by eightfold, minimizes lithium ion dissolution, and facilitates efficient electrophoretic deposition with improved adherence to current collectors, while maintaining lithium ion transfer capabilities during battery cycling.

Implementation Method 1

solid carbon dioxide to convert surface impurities on cathode particles into lithium carbonate coatings

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

cathode particles are encapsulated in micelles and suspended in the e-coat bath. These micelles (including cathode particles with binders and carbon) are charged particles (for example negatively charged) and under anodic e-coat they migrate towards positively charged anode (Aluminum) where they deposit

Methodology Applied

Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 3

Lithium is very active electronegatively, so it can oxidize any metal surface which is more electropositive than it. For example, lithium ions (under anodic e-coat process) attack the aluminum current collector and oxidize its surface (a process called passivation)

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11296313B2Carbon dioxide treatment of cathodes

Publication Date: 2022.04.05 UCHICAGO ARGONNE LLC

AI summary

A method for producing water resistant cathodes is discussed. The method uses mixing cathode powder with solid carbon dioxide to create a mixture and heating the mixture to a temperature. The heating occurs for a time sufficient to cause lithium carbonate coatings to form on the powder. A method for coating lithium-containing cathode surfaces is also discussed. This method uses simultaneously sublimating solid CO2 and condensing atmospheric water vapor onto surfaces. Afterwards allowing the lithium to react with the sublimated CO2 for a time sufficient to create a lithium carbonate film on the surface.