Ni-Rich Cathode Surface Protection for Lower Reaction Resistance

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Solution Overview

Problem

Lithium-containing transition metal composite oxides with high Ni content used as positive electrode active materials in non-aqueous electrolyte secondary batteries experience increased reaction resistance due to side reactions with the electrolyte, leading to reduced charge-discharge cycle characteristics.

Innovation Solution

Incorporating a sulfonate compound on the surface of the lithium-containing transition metal composite oxide and adding a compound including elements like P, Ca, Sr, B, Zr, Er, or Ti in the positive electrode mixture layer to protect the oxide from hydrogen fluoride generated by side reactions, thereby reducing reaction resistance and improving cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium-containing transition metal composite oxides with high Ni content are used as positive electrode active materials, then battery capacity is improved, but reaction resistance increases due to side reactions with electrolyte

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a protective coating layer comprising compounds of P, Ca, Sr, B, Zr, Er, or Ti on the surface of the lithium-containing transition metal composite oxide. This intermediary layer acts as a barrier between the high-Ni active material and the electrolyte, preventing direct contact and side reactions that would otherwise increase reaction resistance and degrade cycle characteristics, while allowing the high capacity of the Ni-rich material to be maintained.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface composition parameters of the positive electrode active material by incorporating specific elements (P, Ca, Sr, B, Zr, Er, Ti) in controlled amounts. This changes the surface chemistry and reactivity parameters, reducing the harmful interactions with electrolyte while preserving the bulk electrochemical performance that provides high battery capacity.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If lithium-containing transition metal composite oxides with high Ni content are used, then battery capacity increases, but reaction resistance increases due to hydrogen fluoride generation

Engineering Contradiction:

Improvebattery capacityVSAvoidreaction resistance

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of hydrogen fluoride generation into a beneficial protective mechanism. The protective coating layer is specifically designed to react with or resist hydrogen fluoride, transforming the harmful byproduct of high-Ni material operation into a controlled interaction that actually strengthens the protective barrier and reduces overall reaction resistance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If protective additives are added to the positive electrode mixture layer, then cycle characteristics are improved, but device complexity increases

Engineering Contradiction:

Improvecycle characteristicsVSAvoidpositive electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a composite positive electrode material by combining the lithium-containing transition metal composite oxide with compounds of P, Ca, Sr, B, Zr, Er, or Ti. This composite structure integrates the high-capacity Ni-rich core with protective surface components, achieving improved cycle characteristics without requiring separate protective layers or complex multi-component systems.

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 proposed solution effectively reduces reaction resistance and enhances the cycle characteristics of the battery by protecting the lithium-containing transition metal composite oxide from hydrogen fluoride, maintaining battery performance.

Implementation Method 1

adding a compound including elements like P, Ca, Sr, B, Zr, Er, or Ti in the positive electrode mixture layer to protect the oxide from hydrogen fluoride generated by side reactions

Methodology Applied

Scientific EffectChemical protection:

Data Source

PatentEP4704169A1Positive electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

Publication Date: 2026.03.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

Figure 1

AI summary

A positive electrode (11) for nonaqueous electrolyte secondary batteries according to the present disclosure is characterized by having a positive electrode core body and a positive electrode mixture layer formed on the surface of the positive electrode core body, and is characterized in that: the positive electrode mixture layer contains a positive electrode active material and an additive; the positive electrode active material contains a lithium-containing transition metal composite oxide having a layered structure; the lithium-containing transition metal composite oxide is composed of secondary particles formed by aggregation of primary particles; a sulfonic acid compound represented by formula (I) is present on the surfaces of the secondary particles; and the additive includes a compound containing at least one element selected from the group consisting of P, Ca, Sr, B, Zr, Er, Ti, and Al. (In the formula, A represents a group 1 element or a group 2 element, R represents a hydrocarbon group, and n is 1 or 2.)