Spherical Cathode Particles with Encapsulated Conductive Domains

Solution Overview

Problem

Lithium-ion batteries face issues with cycle stability, service life, and safety concerns such as short circuits and thermal stress, and conventional coatings like Al2O3, TiO2, or BaO reduce current carrying capacity and lead to particle detachment over time.

Innovation Solution

Development of spherical particles comprising mixed transition metal hydroxides or carbonates with Ba, Al, or Ti, where at least 75% of the fluoride or oxide is encapsulated within the transition metal hydroxide or carbonate, enhancing safety without compromising current carrying capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coatings like Al2O3, TiO2, or BaO are applied to cathode materials, then safety against short circuits and thermal stress is improved, but current carrying capacity is significantly reduced

Engineering Contradiction:

ImprovesafetyVSAvoidcurrent carrying capacity

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent embeds electrically conductive particles (graphite, carbon nanotubes, or metal particles) within the electrically non-conductive coating layers of Al2O3, TiO2, or BaO. This nested structure allows the coating to provide safety protection while the embedded conductive particles maintain electrical conductivity and current carrying capacity throughout the coating layer.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent creates a composite coating structure combining electrically non-conductive materials (Al2O3, TiO2, BaO) with electrically conductive materials (graphite, carbon nanotubes, metal particles). This composite approach allows the coating to simultaneously provide safety protection through the non-conductive matrix while maintaining electrical conductivity through the conductive dispersed phase.

Inventive Principle:

Principle #40Composite materials

2Reliability

If cathode materials are coated with electrically non-conductive compounds, then safety is improved, but connection to current conductor deteriorates

Engineering Contradiction:

ImprovesafetyVSAvoidconnection to current conductor

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent creates a composite coating structure combining electrically non-conductive materials (Al2O3, TiO2, BaO) with electrically conductive materials (graphite, carbon nanotubes, metal particles). This composite approach allows the coating to simultaneously provide safety protection through the non-conductive matrix while maintaining electrical conductivity through the conductive dispersed phase.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent embeds electrically conductive particles (graphite, carbon nanotubes, or metal particles) within the electrically non-conductive coating layers of Al2O3, TiO2, or BaO. This nested structure allows the coating to provide safety protection while the embedded conductive particles maintain electrical conductivity and current carrying capacity throughout the coating layer.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If coatings are applied to cathode materials, then safety is improved, but coating detachment occurs during aging

Engineering Contradiction:

ImprovesafetyVSAvoidcoating stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies different materials with different properties at different locations within the coating: the outer layer consists of electrically non-conductive materials (Al2O3, TiO2, BaO) for safety protection, while embedded throughout are electrically conductive particles (graphite, carbon nanotubes, metal particles) that also serve as anchoring points. This localized differentiation improves both safety and adhesion stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite coating structure combining electrically non-conductive materials (Al2O3, TiO2, BaO) with electrically conductive materials (graphite, carbon nanotubes, metal particles). This composite approach allows the coating to simultaneously provide safety protection through the non-conductive matrix while maintaining electrical conductivity through the conductive dispersed phase.

Inventive Principle:

Principle #40Composite materials

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 spherical particles improve the safety and stability of lithium-ion batteries by maintaining current carrying capacity and preventing particle detachment, thereby extending the battery's service life and reducing the risk of short circuits and thermal stress.

Implementation Method 1

a sparingly soluble compound or a mixture of several sparingly soluble compounds is first precipitated from one or more solutions of transition metal salts

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentEP2994423B1Spherical particles, their preparation and use

Publication Date: 2018.01.03 BASF SE

Figure 1

AI summary

The invention relates to spherical particles, containing (A) at least one mixed transition metal hydroxide or mixed transition metal carbonate comprising at least 3 different transition metals selected from nickel, cobalt, manganese, iron, chromium and vanadium, (B) at least one fluoride, oxide or hydroxide of Ba, Al, Zr or Ti, wherein the transition metals in transition metal hydroxide (A) or transition metal carbonate (A) are predominantly present in oxidation stage +2, wherein at least 75% of fluoride (B) or oxide (B) or hydroxide (B) is present in the form of domains in an outer shell of the spherical particles and are at least 90% covered by transition metal hydroxide (A) and/or transition metal carbonate (A).