Sulfonic Acid Surface Coating for High-Rate NCA Cathode Materials

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Solution Overview

Problem

Secondary batteries using NCA-based lithium-containing composite oxides face a challenge in maintaining high discharge capacity at high rates, as existing technologies do not effectively balance high capacity and improved output characteristics.

Innovation Solution

A positive electrode active material is developed, comprising a lithium-containing composite oxide with a layered rock salt structure, containing 80 mol % or more of Ni, 1.5 mol % or more of Co, and 4 mol % or more of Al, and a sulfonic acid compound represented by a specific general formula attached to its surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If NCA-based lithium-containing composite oxide is used as positive electrode active material, then high capacity is achieved, but discharge capacity at high rate deteriorates

Engineering Contradiction:

Improvedischarge capacityVSAvoiddischarge capacity at high rate

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent applies local quality by creating a dual-structure positive electrode active material where the core region contains NCA-based lithium-containing composite oxide for high capacity, while the surface region contains lithium titanate for improved rate performance. This spatial differentiation of material properties allows the core to provide capacity while the surface facilitates rapid ion transport, resolving the contradiction between high capacity and high rate discharge characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining NCA-based lithium-containing composite oxide with lithium titanate to form a composite positive electrode active material. The NCA core provides high capacity through its nickel-rich composition, while the lithium titanate surface layer provides excellent rate capability through its zero-strain insertion mechanism. This composite structure synergistically integrates the advantages of both materials, achieving both high capacity and improved high-rate discharge performance

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250029994A1Positive electrode active material for non-aqueous electrolyte secondary battery, positive electrode for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, and method for manufacturing positive electrode active material for non-aqueous electrolyte secondary battery

Publication Date: 2025.01.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Provided is a positive electrode active material having a high capacity and improved output characteristics. The positive electrode active material included in this non-aqueous electrolyte secondary battery includes a lithium-containing complex oxide having a layered rock salt structure, and a sulfonic acid compound that is present on the surface of the lithium-containing complex oxide. The lithium-containing complex oxide contains 80 mol % or more of Ni, 1.5 mol % or more of Co, and 4 mol % or more of Al based on the total molar number of metal elements excluding Li. The sulfonic acid compound is represented by the general formula I. (In the formula, A is a Group 1 element or a Group 2 element, R is a hydrocarbon group, and n is 1 or 2.)