Dual-Layer Sodium-Ion Cathode for Higher First-Cycle Capacity

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Solution Overview

Problem

Tunnel-type oxide materials used as positive electrode materials in sodium-ion batteries have limited sodium ion deintercalation during the first cycle, leading to extremely low charge and discharge capacity, restricting their practical application.

Innovation Solution

A sodium-ion battery design incorporating a positive electrode plate with a first layer of tunnel-type oxide and a second layer of P2 and/or O3 type layered oxide, enhancing sodium ion deintercalation capacity by providing additional sodium ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tunnel-type oxide materials are used as positive electrode materials, then structural stability and ionic conductivity are improved, but charge and discharge capacity deteriorates due to limited sodium ion deintercalation

Engineering Contradiction:

Improvestructural stabilityVSAvoidcharge and discharge capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies composite materials by combining tunnel-type oxide materials with P2 and/or O3 type layered oxide materials to form a composite positive electrode. The layered oxide component provides additional sodium ion deintercalation capacity while the tunnel-type oxide maintains structural stability, thus resolving the contradiction between reliability and quantity of substance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the positive electrode material into two distinct layers: a first layer containing tunnel-type oxide material and a second layer containing P2 and/or O3 type layered oxide material. This segmentation allows each layer to perform its specialized function - the tunnel-type layer provides structural stability while the layered oxide layer enhances sodium ion deintercalation capacity.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If tunnel-type oxide materials are used as positive electrode materials, then ease of manufacture is improved by leveraging existing lithium battery processing conditions, but charge and discharge capacity deteriorates

Engineering Contradiction:

Improveease of manufactureVSAvoidcharge and discharge capacity

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent uses composite materials combining tunnel-type oxide and P2/O3 layered oxide, where the tunnel-type oxide component can be processed using existing lithium battery manufacturing conditions, maintaining ease of manufacture while the layered oxide component compensates for the limited sodium ion deintercalation capacity.

Inventive Principle:

Principle #40Composite materials

3Device complexity

If a single layer of tunnel-type oxide is used, then device complexity is reduced, but charge and discharge capacity deteriorates due to limited sodium ion deintercalation

Engineering Contradiction:

Improvedevice complexityVSAvoidcharge and discharge capacity

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The patent segments the positive electrode into two functional layers with distinct compositions and roles. The first layer contains tunnel-type oxide material while the second layer contains P2 and/or O3 type layered oxide material. This segmentation increases sodium ion deintercalation capacity while maintaining relatively simple device structure and manufacturing processes.

Inventive Principle:

Principle #1Segmentation

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 dual-layered structure increases the discharge capacity of sodium-ion batteries by allowing more sodium ions to be deintercalated, improving charge and discharge performance.

Implementation Method 1

the sodium ions that may be deintercalated during the first cycle of charging of the batteries are limited

Methodology Applied

Scientific EffectDeintercalation:

Implementation Method 2

Both the tunnel-type oxide and the layered oxide may provide sodium ions during charging

Methodology Applied

Scientific EffectIntercalation:

Data Source

PatentEP4693572A1Sodium ion battery and electric device

Publication Date: 2026.02.11 SUNWODA MOBILITY ENERGY TECHNOLOGY CO LTD

Figure 1

AI summary

The present disclosure discloses a sodium-ion battery and an electric device. The sodium-ion battery includes a positive electrode plate, and the positive electrode plate includes a positive electrode current collector, a first positive electrode material layer disposed on at least one surface of the positive electrode current collector, and a second positive electrode material layer disposed on the first positive electrode material layer; the first positive electrode material layer includes a first positive electrode material, and the first positive electrode material includes a tunnel-type oxide; and the second positive electrode material layer includes a second positive electrode material, and the second positive electrode material includes a P2 and/or O3 type layered oxide.