Li3BO3-Coated Nickel-Rich Cathode Material for Air Stability

Solution Overview

Problem

Lithium-nickel composite oxide positive electrode active materials in non-aqueous electrolyte secondary batteries deteriorate quickly when exposed to the atmosphere, leading to reduced capacity and increased reaction resistance, which limits their use and market expansion due to the need for specialized manufacturing conditions.

Innovation Solution

A lithium-nickel composite oxide positive electrode active material is developed with a surface coating of Li3BO3, where the boron content is between 0.001% and 0.2% by mass, which suppresses atmospheric deterioration and maintains high battery capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium-nickel composite oxide is used as positive electrode active material, then battery capacity is improved and cost is reduced, but atmospheric deterioration occurs causing capacity decrease and reaction resistance increase

Engineering Contradiction:

Improvebattery capacityVSAvoidatmospheric stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent uses a composite material structure where lithium-nickel composite oxide particles are coated with lithium borate. This composite structure combines the high capacity properties of lithium-nickel oxide with the protective and stabilizing properties of lithium borate, resolving the contradiction between high capacity and atmospheric stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality modification by coating only the surface of lithium-nickel composite oxide particles with lithium borate. The core material maintains its high-capacity nickel-rich composition while the surface layer provides atmospheric stability, allowing different regions of the material to have different functional properties.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If lithium-nickel composite oxide with high nickel ratio is used, then battery capacity is improved, but reactivity with atmosphere increases causing faster deterioration

Engineering Contradiction:

Improvebattery capacityVSAvoidatmospheric reactivity

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The lithium borate coating acts as an intermediary layer between the lithium-nickel composite oxide and the atmosphere. This intermediate layer prevents direct contact and reaction between the reactive nickel-rich material and atmospheric components, reducing harmful atmospheric reactivity while preserving the high capacity properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality modification by coating only the surface of lithium-nickel composite oxide particles with lithium borate. The core material maintains its high-capacity nickel-rich composition while the surface layer provides atmospheric stability, allowing different regions of the material to have different functional properties.

Inventive Principle:

Principle #3Local quality

3Reliability

If lithium-cobalt composite oxide is used, then excellent initial and cycle characteristics are obtained, but unit price per capacity becomes significantly higher

Engineering Contradiction:

Improvecycle characteristicsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive cobalt-based materials with cheaper nickel-based materials. While nickel-rich materials have shorter atmospheric stability 'life' when uncoated, the addition of a thin lithium borate coating layer restores durability, making the cheaper material viable while maintaining good cycle characteristics.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses a composite material structure where lithium-nickel composite oxide particles are coated with lithium borate. This composite structure combines the high capacity properties of lithium-nickel oxide with the protective and stabilizing properties of lithium borate, resolving the contradiction between high capacity and atmospheric stability.

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 surface coating with Li3BO3 effectively prevents deterioration of battery characteristics, allowing the battery to maintain capacity and reduce reaction resistance, enabling the use of these batteries in standard atmospheric conditions without the need for specialized equipment.

Implementation Method 1

at least a part of a surface of the lithium-nickel composite oxide is coated with Li3BO3

Methodology Applied

Scientific EffectSurface coating: Coatings

Data Source

PatentUS11862793B2Positive electrode active material for non-aqueous electrolyte secondary battery and method for producing the same, and non-aqueous electrolyte secondary battery and method for producing the same

Publication Date: 2024.01.02 SUMITOMO METAL MINING CO LTD

AI summary

The positive electrode active material is for a non-aqueous electrolyte secondary battery, suppressing deterioration of battery characteristics due to exposure to the atmosphere and having excellent battery capacity. A positive electrode active material for a non-aqueous electrolyte secondary battery includes a lithium-nickel composite oxide represented by general formula (1): LiaNi1−x−yCoxMyO2+α (in which 0.05≤x≤0.35, 0≤y≤0.10, 0.95≤a≤1.10, 0≤a≤0.2, and M represents at least one element selected from Mn, V, Mg, Mo, Nb, Ti, W, and Al) and Li3BO3. At least a part of a surface of the lithium-nickel composite oxide is coated with Li3BO3. The content of boron in the positive electrode active material is 0.001% by mass or more and 0.2% by mass or less with respect to the entire positive electrode active material.