Silicon-Carbon Negative Electrode with Lanthanide Ion Pathways

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Solution Overview

Problem

The energy density of lithium-ion batteries is insufficient, and silicon-based materials used to increase energy density suffer from significant volume changes during charge and discharge cycles, leading to deteriorated conductivity and cycling performance due to pulverization and detachment from the current collector.

Innovation Solution

A negative electrode plate comprising a silicon-carbon composite material and a lanthanide compound, such as Li3xLa2/3-xTiO3, is used to improve ion transport and lithium intercalation uniformity, with the lanthanide compound distributed in pores of the active material layer to form solid-solid contacts, enhancing the ion channel network and reducing swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If silicon-based material is added to increase energy density, then energy density is improved, but volume change during charge and discharge causes pulverization and detachment

Engineering Contradiction:

Improveenergy densityVSAvoidcycling performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A carbon coating layer is formed on the surface of the silicon-based material particles, creating a flexible protective shell that accommodates volume expansion and contraction during lithium insertion and extraction. This carbon shell prevents direct contact between silicon and electrolyte, reducing pulverization while maintaining structural integrity through multiple cycles.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The negative electrode uses a composite structure combining silicon-based material with carbon material (such as graphite). The silicon provides high capacity while the carbon matrix provides structural stability and conductivity. This composite approach allows the silicon to expand within the carbon framework without detaching from the current collector, thus maintaining cycling performance while achieving high energy density.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If silicon-based material undergoes volume change during cycling, then lithium intercalation capacity is improved, but ion channel disconnection occurs

Engineering Contradiction:

Improvelithium intercalation capacityVSAvoidion channel connectivity

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The negative electrode active material layer is designed with a porous structure that provides three-dimensional ion transport channels. These pores accommodate the volume change of silicon-based material during lithium insertion and extraction, preventing ion channel disconnection. The porous structure maintains continuous electrolyte access to silicon particles throughout cycling, ensuring stable ion transport while enabling high lithium intercalation capacity.

Inventive Principle:

Principle #31Porous materials

3Quantity of substance

If silicon material expands during lithium insertion, then capacity is improved, but detachment from current collector occurs

Engineering Contradiction:

Improvebattery capacityVSAvoidadhesion to current collector

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The negative electrode employs a composite structure where silicon-based material is embedded in a carbon-containing matrix that is firmly attached to the current collector. This composite structure distributes the expansion stress of silicon across the entire electrode layer, preventing localized detachment. The carbon matrix acts as a buffer that maintains mechanical contact between silicon particles and current collector during volume changes, preserving both capacity and adhesion.

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

This design increases energy density and improves cycling performance by stabilizing the silicon-carbon composite material, reducing swelling, and enhancing ion transport capability.

Implementation Method 1

the lanthanide compound is distributed in pores of the negative electrode active material layer and forms solid-solid contact with the silicon-carbon composite material

Methodology Applied

Scientific EffectSolid-solid contact:

Implementation Method 2

the silicon material undergoes a volume change of 120% to 300% with intercalation and deintercalation of lithium ions

Methodology Applied

Scientific EffectVolume change:

Data Source

PatentUS20250273664A1Negative electrode plate, battery, and electric apparatus

Publication Date: 2025.08.28 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side surface of the negative electrode current collector, where the negative electrode active material layer includes a silicon-carbon composite material and a lanthanide compound.