Double-Layer Positive Electrode for Low-Temperature Li-Ion Batteries

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Solution Overview

Problem

Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, and high conductivity, particularly at low temperatures.

Innovation Solution

A positive electrode for rechargeable lithium batteries is designed with a double layer structure, comprising a first active material layer and a second active material layer, where each layer includes specific particles with defined elemental compositions and coating layers to enhance structural stability and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single layer structure is used, then the manufacturing process is simple, but the energy density and conductivity are insufficient

Engineering Contradiction:

Improvestructure complexityVSAvoidenergy density

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The positive electrode active material layer is segmented into two distinct layers: a first layer containing LiFePO4 particles and a second layer containing LiNi0.8Co0.1Mn0.1O2 particles. This segmentation allows each layer to contribute different properties, with the first layer providing structural stability and the second layer providing high capacity, thereby resolving the contradiction between structural simplicity and high energy density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite materials by combining two different lithium-containing compounds in a layered structure. The LiFePO4-based compound in the first layer and the LiNi0.8Co0.1Mn0.1O2-based compound in the second layer form a composite system that achieves both high energy density and good structural stability, overcoming the limitation of single-material electrodes.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If high capacity materials are used, then the energy density increases, but the structural stability decreases

Engineering Contradiction:

Improveenergy densityVSAvoidstructural stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The electrode is segmented into two functional layers where the first layer (LiFePO4-based) provides structural stability and the second layer (LiNi0.8Co0.1Mn0.1O2-based) provides high capacity. This segmentation allows high capacity materials to be used without compromising overall structural stability, as the stable first layer acts as a foundation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode are assigned different qualities: the first layer near the current collector is designed with high structural stability (LiFePO4-based), while the second layer is designed with high capacity (LiNi0.8Co0.1Mn0.1O2-based). This local differentiation resolves the contradiction by placing stable materials where structural support is needed and high-capacity materials where energy storage is prioritized.

Inventive Principle:

Principle #3Local quality

3Power

If the conductivity is improved, then the operating voltage increases, but the low-temperature performance deteriorates

Engineering Contradiction:

Improveoperating voltageVSAvoidlow-temperature properties

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The composite structure combines LiFePO4-based compound with good low-temperature performance in the first layer and LiNi0.8Co0.1Mn0.1O2-based compound with high operating voltage in the second layer. This composite approach allows the battery to maintain both high operating voltage and acceptable low-temperature performance by leveraging the strengths of each material.

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 double layer structure improves the battery's energy density, operating voltage, and conductivity, particularly at low temperatures, leading to enhanced performance and extended lifespan.

Implementation Method 1

each including an active material that allows or facilitates the intercalation and deintercalation of lithium ions

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

These batteries generate (produce) electrical energy from redox reactions (e.g., oxidation and reduction reactions) that occur as lithium ions are intercalated into or deintercalated from the positive electrode and the negative electrode

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS20250336945A1Positive electrode for rechargeable lithium battery, and rechargeable lithium battery including the same

Publication Date: 2025.10.30 SAMSUNG SDI CO LTD

AI summary

A rechargeable lithium battery including a positive electrode, the positive electrode including a current collector, a first active material layer on the current collector, and a second active material layer on the first active material layer, wherein the first active material layer and the second active material layer each include a first particle, and the second active material layer further includes a second particle. The first particle is an olivine-based particle, and the second particle is a layered particle.