Silicon Anode Coating via Pyrolyzed Acidic Polyamide Imide

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional battery electrodes face issues with electrode coating layers losing contact due to large volume changes of silicon anodes during lithiation and delithiation, leading to reduced cycle life and energy density.

Innovation Solution

The use of water-soluble acidified polyamide imide (PAI) and water-based acidic polymer solution additives as carbon precursors for silicon-dominant anodes, which improve adhesion, cycle life, and energy density by forming a stable electrode coating layer that maintains electrical contact during volume changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional battery electrode approaches are used, then manufacturing is simpler, but electrode coating layers lose contact with the electrode due to large volume changes of silicon anodes during lithiation and delithiation

Engineering Contradiction:

Improveadhesion of electrode coating layerVSAvoidcomplexity of electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite electrode structure consisting of a current collector, silicon-containing active material particles, and a carbon coating layer. This composite design allows the carbon layer to accommodate the large volume changes of silicon during lithiation/delithiation while maintaining electrical contact and structural integrity, thereby improving adhesion and reliability without excessive complexity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The carbon coating layer acts as a flexible shell that envelops the silicon-containing active material particles. This thin film structure can expand and contract with the silicon particles during charge-discharge cycles, preventing coating layer detachment while maintaining electrical conductivity and structural stability

Inventive Principle:

Principle #30Flexible shells and thin films

2Quantity of substance

If silicon-dominant anodes with high silicon content are used, then energy density increases, but cycle life decreases due to coating layer contact loss

Engineering Contradiction:

Improveenergy densityVSAvoidcycle life

Core Design Contradiction:

Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The patent optimizes the carbon-to-silicon ratio in the electrode coating layer and controls the carbonization process parameters (temperature, atmosphere, time) to create a carbon layer with appropriate thickness, porosity, and mechanical properties. This parameter optimization allows the electrode to maintain high silicon content for energy density while the carbon layer provides structural stability for extended cycle life

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The carbon coating layer is formed beforehand to cushion and accommodate the large volume expansion of silicon during lithiation. This pre-formed protective layer prevents direct exposure of silicon to the electrolyte and prevents coating layer detachment during subsequent charge-discharge cycles, thereby extending cycle life while maintaining high energy density

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If standard anode structures are used, then manufacturing costs are lower, but performance in terms of cycle life and adhesion is inferior

Engineering Contradiction:

Improvecycle life and adhesionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes carbon precursors that are already present in the slurry mixture (such as polyacrylonitrile, polyvinylidene fluoride, or other polymer binders) to form the carbon coating layer through in-situ carbonization during the first charge cycle or a controlled heat treatment step. This self-forming approach eliminates the need for separate carbon coating processes, reducing manufacturing complexity and cost while achieving superior adhesion and cycle life

Inventive Principle:

Principle #25Self-service

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

The solution enhances the cycle life, energy density, power density, flexibility, and adhesion of silicon-dominant anodes, enabling them to perform similarly or better than standard anodes while reducing costs.

Implementation Method 1

the electrode coating layer is formed from silicon and pyrolyzed water-soluble acidic polyamide imide resin carbon precursor

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS11699786B2Method and system for water soluble weak acidic resins as carbon precursors for silicon-dominant anodes

Publication Date: 2023.07.11 ENEVATE CORP

AI summary

Systems and methods for water soluble weak acidic resins as carbon precursors for silicon-dominant anodes may include an electrode coating layer on a current collector, where the electrode coating layer is formed from silicon and pyrolyzed water-soluble acidic polyamide imide as a primary resin carbon precursor. The electrode coating layer may include a pyrolyzed water-based acidic polymer solution additive. The polymer solution additive may include one or more of: polyacrylic acid (PAA) solution, poly (maleic acid, methyl methacrylate/methacrylic acid, butadiene/maleic acid) solutions, and water soluble polyacrylic acid. The electrode coating layer may include conductive additives. The current collector may include a metal foil, where the metal current collector includes one or more of a copper, tungsten, stainless steel, and nickel foil in electrical contact with the electrode coating layer. The electrode coating layer may be more than 70% silicon.