Sodium Cathode Composition for Stable Deintercalation Cycling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing sodium-ion batteries using layered transition metal oxides suffer from poor initial coulombic efficiency and cycling performance due to structural instability during sodium deintercalation, leading to irreversible changes and side reactions with the electrolyte.

Innovation Solution

A positive electrode active material with specific cation compositions and ionic potentials, including manganese, iron, and other ions, forms strong covalent bonds with oxygen, stabilizing the structure during sodium deintercalation, thereby improving initial coulombic efficiency and cycling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If layered transition metal oxides are used as positive electrode active materials, then the battery can store and release sodium ions, but the structural instability during sodium deintercalation leads to poor initial coulombic efficiency and cycling performance

Engineering Contradiction:

Improvecycling performanceVSAvoidstructural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs composite materials by combining layered transition metal oxides with three-dimensional oxide frameworks (such as RuO2, IrO2, or their mixed oxides) to create a hybrid structure. This composite approach allows the material to maintain the sodium storage capability of layered structures while gaining the structural stability of three-dimensional frameworks, thereby resolving the contradiction between reliability and compositional stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by modifying the chemical composition and crystal structure parameters of the positive electrode material. Specifically, it adjusts the ratio of layered oxide to three-dimensional oxide, controls the crystal phase (O3 or P2 type), and optimizes the ionic potential parameters (ΣBi×Ii4≥1500 Å−4) to enhance both cycling performance and structural stability simultaneously.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If layered transition metal oxides undergo sodium deintercalation, then charge-discharge cycles can occur, but oxygen atom repulsion increases causing structural changes and side reactions with electrolyte

Engineering Contradiction:

Improvecharge-discharge capabilityVSAvoidside reactions with electrolyte

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces three-dimensional oxide framework materials (RuO2, IrO2, or mixed oxides) as intermediary structures that mediate between the layered transition metal oxide and the electrolyte. These intermediary frameworks provide stable pathways for sodium ion transport while preventing direct contact between the layered oxide and electrolyte, thereby enabling charge-discharge cycles without generating harmful side reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of oxygen atom repulsion during sodium deintercalation into a beneficial outcome by designing a composite structure where the three-dimensional oxide framework absorbs and distributes the structural stress. The framework's high ionic potential and structural rigidity transform the potentially harmful repulsion forces into stabilized lattice expansions that enhance overall cycling stability while maintaining productivity.

Inventive Principle:

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

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 material enhances the structural stability of the positive electrode, reducing oxygen atom repulsion and suppressing side reactions, resulting in improved initial coulombic efficiency and cycling performance of sodium-ion batteries.

Implementation Method 1

the cations include manganese ions, iron ions, M ions, and N ions; and ΣBi×Ii4≥1500 Å−4... the positive electrode active material maintains structural stability during deintercalation of sodium

Methodology Applied

Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

the ionic potential of the N ions is greater than or equal to 5 Å−1... ΣBi×Ii4≥1500 Å−4, where Bi is the molar fraction of cations, Ii is the ionic potential of the cations

Methodology Applied

Scientific EffectIonic potential effect:

Implementation Method 3

maintains structural stability during deintercalation of sodium, thereby improving the initial coulombic efficiency and cycling performance of a battery... reducing oxygen atom repulsion

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS20260049003A1Positive electrode active material and preparation method thereof, positive electrode plate, battery, and electric device

Publication Date: 2026.02.19 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

AI summary

A positive electrode active material and a preparation method thereof, a positive electrode plate, a battery, and an electric device. The positive electrode active material includes: NaxMnaFebMcNdO2+δ−eFe, where 0.5≤x≤1.1, a≥0, b≥0, c≥0, d>0, a+b +c+d=1, −0.1≤δ≤0.1, and e≥0; M ions include at least one of Ni2+, Ni3+, Cu2+, Cu+, Zn2+, Mg2+, Y3+, La3+, In3+, Sb3+, Li+, Sn2+, and Ag+; ΣBi×Ii4≥1500 Å−4, where Bi is a molar fraction of cations, Ii is an ionic potential of the cations, in unit of Å−1, and the cations include manganese ions, iron ions, M ions, and N ions; and the ionic potential of the N ions is greater than or equal to 5 Å−1.