Secondary battery positive electrode and secondary battery

By integrating an electrochemically inert ionic compound with specific properties into the positive electrode mixture layer, the peel strength is improved, addressing the de-HF reaction issue and ensuring robust battery performance with reduced PVDF content.

WO2026140578A1PCT designated stage Publication Date: 2026-07-02PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
Filing Date
2025-11-13
Publication Date
2026-07-02

AI Technical Summary

Technical Problem

The peel strength of the positive electrode mixture layer in secondary batteries is compromised when using lithium-containing transition metal oxide particles in single-particle form due to the de-HF reaction between PVDF and these particles, leading to coating defects and reduced binding properties, which cannot be effectively addressed by increasing the PVDF content.

Method used

Incorporating an electrochemically inert ionic compound with a cation and oxygen having a 1.7 or less electronegativity difference, and an average particle size of 3 μm or less, into the positive electrode mixture layer, ensuring a high overlap ratio with PVDF, maintains binding properties even at low PVDF content.

Benefits of technology

The solution significantly enhances the peel strength of the positive electrode mixture layer, preventing coating defects and maintaining battery performance while minimizing PVDF usage.

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Abstract

A positive electrode mixture layer of this secondary battery positive electrode contains a positive electrode active material, a binder, and an ion-binding compound. The positive electrode active material contains lithium-containing transition metal oxide particles in at least one of a form of single primary particles and a form of secondary particles in which 2-5 primary particles are aggregated. The binder contains PVDF. The difference in electronegativity between oxygen and the cation of the ion-binding compound is 1.7 or more. The PVDF content is 1 mass % or less. When the positive electrode mixture layer is subjected to elemental analysis using EPMA, the proportion of the number of aggregates of a specific element indicating the ion-binding compound which are detected overlapping with the F element detected in a region from a current collector to 50% of the total thickness of the positive electrode mixture layer, relative to the total number of aggregates of the specific element indicating the ion-binding compound which are detected in said region, is 70% or more.
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