Hollow Positive Electrode Material with Electronic Conductor Coating

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Solution Overview

Problem

Lithium secondary batteries face challenges in reducing battery resistance, which affects their performance and efficiency, despite advancements in positive electrode active materials.

Innovation Solution

A positive electrode material with a hollow structure and an electronic conductor on its surface, composed of lithium-transition metal composite oxides and a specific electronic conductor, is developed to enhance charge transfer and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If hollow particles with through-holes are used as positive electrode active material, then the reaction surface area is increased, but the battery resistance is not sufficiently reduced

Engineering Contradiction:

Improvereaction surface areaVSAvoidbattery resistance

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent employs hollow particles with through-holes as the positive electrode active material, creating a porous structure that significantly increases the reaction surface area. This porous configuration allows electrolyte penetration throughout the particle interior, providing numerous active sites for lithium ion insertion and extraction, thereby reducing battery resistance.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent creates a composite structure by coating the hollow particle surface with an electronic conductor layer. This composite configuration combines the high surface area advantage of hollow particles with the enhanced electrical conductivity of the conductor coating, effectively reducing battery resistance while maintaining increased reaction surface area.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If the positive electrode active material particles are made hollow, then the energy density is improved, but the structural stability deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidstructural stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent utilizes a thin electronic conductor coating layer on the hollow particle surface that acts as a flexible protective shell. This thin film structure maintains the hollow configuration for high energy density while providing mechanical support and structural stability during charging and discharging cycles.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The electronic conductor coating serves as a protective layer that cushions and distributes mechanical stresses before they can cause structural failure. This pre-protective configuration prevents crack propagation and maintains structural integrity throughout battery operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If the surface area of positive electrode active material is increased, then the charge transfer is enhanced, but the manufacturing complexity increases

Engineering Contradiction:

Improvecharge transfer rateVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the positive electrode active material into numerous small hollow particles with through-holes, creating segmented structures that collectively provide large surface area. This segmentation approach enhances charge transfer by distributing reaction sites throughout the electrode while maintaining manufacturability through conventional particle synthesis methods.

Inventive Principle:

Principle #1Segmentation

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 material significantly reduces battery resistance and improves durability by increasing the reaction surface area and maintaining conductive paths even after cracking, leading to higher energy density and thermal stability.

Implementation Method 1

an electronic conductor present on the surface of the particles of the positive electrode active material

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

particles of a positive electrode active material, each having a void communicating between the surface and at least the interior

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS11374210B2Positive electrode material

Publication Date: 2022.06.28 TOYOTA JIDOSHA KK

AI summary

Provided is a positive electrode material that allows reducing battery resistance. The positive electrode material disclosed herein has particles of a positive electrode active material, each having a void communicating between the surface and at least the interior; and an electronic conductor present on the surface of the particles of the positive electrode active material. The positive electrode active material has a layered rock salt structure, and has a composition represented by Formula (I) below. The electronic conductor has a composition represented by Formula (II) below,Li1+uNixMnyCozMtO2 (I)La1−pMapCo1−qMbqO3−δ (II)wherein the symbols in the formulas are as defined in the specification.