Composite Coated Carbon Anode for Lithium Battery

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Solution Overview

Problem

Lithium secondary batteries face challenges with anode fabrication due to the hydrophobic nature of carbon-based materials, leading to low miscibility with solvents, non-uniform dispersion, and increased internal resistance, as well as initial irreversible reactions and lithium dendrite growth, which affect battery capacity and lifespan.

Innovation Solution

A composite coating layer is applied to a crystalline carbon-based core, comprising a hydrophilic oxide such as lithium titanium composite oxide, improving miscibility with solvents, reducing irreversible reactions, and inhibiting lithium dendrite growth, while maintaining electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a carbon-based material is used as an anode active material, then high energy density and voltage are achieved, but low miscibility with hydrophilic solvent and non-uniform dispersion occur

Engineering Contradiction:
Improveenergy densityVSAvoiddispersion uniformity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent applies composite materials by combining carbon-based anode active material with hydrophilic oxide particles and conductive material particles. This composite structure allows the hydrophilic oxide to improve solvent miscibility and dispersion uniformity while the carbon-based material maintains high energy density and voltage characteristics.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The hydrophilic oxide acts as an intermediary substance between the hydrophobic carbon-based material and the hydrophilic solvent. It mediates the interaction by providing hydrophilic surfaces that enhance solvent wetting and dispersion while maintaining electrical conductivity through the conductive material component.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If a carbon-based material is used as an anode active material, then high energy density is achieved, but low electrolyte impregnation speed occurs

Engineering Contradiction:
Improveenergy densityVSAvoidimpregnation speed
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent applies local quality by creating a composite structure where hydrophilic oxide particles are distributed on the surface of carbon-based material particles. This local modification of surface properties enhances electrolyte wetting and impregnation speed at the particle level while maintaining the bulk energy density characteristics of the carbon-based material.

Inventive Principle:
Principle #3Local quality

3Reliability

If an oxide layer is formed on the surface of the anode active material, then initial irreversible reaction is reduced, but electrical conductivity deteriorates

Engineering Contradiction:
Improvereaction stabilityVSAvoidelectrical conductivity
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by forming a composite coating on the surface of carbon-based material particles, where hydrophilic oxide provides protective functions and conductive material particles maintain electrical conductivity. This localized functional distribution allows the surface to exhibit both protective and conductive properties simultaneously.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining hydrophilic oxide with conductive material in a specific ratio (0.1-10 wt% conductive material relative to hydrophilic oxide). This composite structure provides both the protective barrier function against irreversible reactions and the electrical conductivity needed for battery operation.

Inventive Principle:
Principle #40Composite materials

4Manufacturing precision

If a surfactant is added to improve miscibility, then solvent dispersion is improved, but side effects on driving properties occur

Engineering Contradiction:
Improvedispersion uniformityVSAvoiddriving properties
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the use of surfactants with a composite material approach using hydrophilic oxide and conductive material particles. This substitution eliminates the need for additional chemical additives that could have side effects, using instead a stable composite structure that provides both dispersion improvement and electrical conductivity without compromising driving properties.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 approach enhances the uniformity and bonding of anode components, reduces impregnation time, improves battery productivity, and extends lifespan by forming a strong SEI layer and preventing lithium dendrite formation.

Implementation Method 1

a composite coating layer comprising a hydrophilic oxide capable of intercalating and deintercalating ions

Methodology Applied
Scientific EffectIntercalation:

Implementation Method 2

a solid electrolyte interface (SEI) layer is formed on the surface of the carbon-based anode active material during an initial charge/discharge process

Methodology Applied
Scientific EffectSolid electrolyte interface (SEI) layer formation:

Data Source

PatentEP2658015B1Cathode active material and secondary battery using same
Publication Date: 2017.11.29 LG CHEM LTD

AI summary

Disclosed are an anode active material for secondary batteries, capable of intercalating and deintercalating ions, the anode active material including a core including a crystalline carbon-based material, and a composite coating layer including one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon, and a hydrophilic material containing oxide capable of intercalating and deintercalating ions, wherein the composite coating layer includes a matrix comprising one component selected from (a) the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon and (b) the hydrophilic material containing oxide capable of intercalating and deintercalating ions, and a filler including the other component, incorporated in the matrix, and a secondary battery including the anode active material.