Sulfonated Elastomer Graphene Composite Anode Coating

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Solution Overview

Problem

Lithium-ion batteries face issues with rapid capacity decay due to mechanical degradation of high-capacity anode active materials like Si and Sn, leading to shortened cycle life, low reversible capacity, and high irreversible capacity, as existing protective coatings are brittle and fail to prevent electrolyte interaction.

Innovation Solution

Development of sulfonated elastomer/graphene composite-encapsulated anode active material particles with a thin layer of sulfonated elastomer/graphene composite, providing high tensile strain recovery, lithium ion conductivity, and electrical conductivity to protect the anode active material from expansion and contraction, while preventing electrolyte interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high-capacity anode active materials like Si and Sn are used, then the reversible capacity is improved, but the mechanical degradation occurs leading to shortened cycle life

Engineering Contradiction:

Improvereversible capacityVSAvoidcycle life

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies a flexible polymer coating shell around high-capacity anode active material particles like Si and Sn. This flexible shell accommodates the volume expansion and contraction during lithium insertion/extraction cycles, preventing mechanical degradation and pulverization of the core particles, thereby maintaining structural integrity and extending cycle life while preserving high reversible capacity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure consisting of a core anode active material (Si or Sn) surrounded by a polymer coating shell. This composite design combines the high capacity benefits of Si/Sn with the mechanical flexibility and stability of the polymer coating, resolving the contradiction between high reversible capacity and cycle life through material composition optimization

Inventive Principle:

Principle #40Composite materials

2Reliability

If protective coatings are applied to prevent mechanical degradation, then the cycle life is improved, but the coatings are brittle and fail to prevent electrolyte interaction

Engineering Contradiction:

Improvecycle lifeVSAvoidelectrolyte interaction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the key parameter of the coating material from brittle inorganic materials to flexible organic polymers. This parameter change in material flexibility allows the coating to dynamically adapt to volume changes during cycling while maintaining continuous coverage, effectively preventing electrolyte contact with the active material throughout the battery's operational life

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If the anode active material particles expand and contract during charge-discharge cycles, then the lithium storage capacity is improved, but the severe pulverization occurs

Engineering Contradiction:

Improvelithium storage capacityVSAvoidparticle integrity

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent implements a polymer coating shell beforehand that acts as a cushioning layer around the anode active material particles. This pre-applied protective shell absorbs and distributes the mechanical stress generated during expansion and contraction, preventing particle pulverization while allowing the core material to undergo the necessary volume changes for high lithium storage capacity

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 sulfonated elastomer/graphene composite effectively enhances the cycle life and reversible capacity of lithium-ion batteries by maintaining the integrity of the anode active material, reducing irreversible capacity, and enabling high-rate capability.

Implementation Method 1

the encapsulating thin layer of sulfonated elastomer/graphene composite has a fully recoverable tensile strain from 2% to 500%

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a lithium ion conductivity from 10^-7 S/cm to 5×10^-2 S/cm

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS10971722B2Method of manufacturing conducting elastomer composite-encapsulated particles of anode active materials for lithium batteries

Publication Date: 2021.04.06 HONEYCOMB BATTERY CO

AI summary

A method of producing a powder mass for a lithium battery, comprising: (a) mixing graphene sheets and a sulfonated elastomer or its precursor in a liquid medium or solvent to form a suspension; (b) dispersing a plurality of particles of an anode active material in the suspension to form a slurry; and (c) dispensing the slurry and removing the solvent and/or polymerizing or curing the precursor to form the powder mass comprising multiple particulates, wherein at least one of the particulates is composed of one or a plurality of the particles encapsulated by a thin layer of a sulfonated elastomer/graphene composite having a thickness from 1 nm to 10 μm, a fully recoverable tensile strain from 2% to 500%, a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm and an electrical conductivity from 10−7 S/cm to 100 S/cm.