Negative Electrode Pre-Lithiation for Uniform Lithium Distribution

Solution Overview

Problem

Existing lithium secondary batteries face issues with non-uniform lithium distribution and irreversible capacity loss due to the formation and collapse of the solid electrolyte interface (SEI) layer, leading to reduced battery capacity and increased manufacturing costs in conventional pre-lithiation methods.

Innovation Solution

A pre-lithiation process is performed on a powder mixture of negative electrode active material, solid electrolyte particle, and conductive agent by contacting them with lithium metal before forming a slurry, ensuring uniform lithium distribution and forming an SEI layer with controlled lithium content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional electrochemical pre-lithiation method is used to deposit Li on the surface of active material, then lithium content is increased, but uniformity of lithium distribution cannot be controlled and manufacturing cost increases

Engineering Contradiction:

Improvelithium contentVSAvoiduniformity of lithium distribution

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-mixing the active material with lithium metal powder before electrode fabrication. This allows lithium to be uniformly distributed throughout the active material matrix from the outset, rather than attempting to deposit it later. The pre-mixed powder is then formed into electrodes, ensuring homogeneous lithium distribution throughout the electrode structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the electrochemical deposition system with a mechanical mixing system. Instead of using electrochemical methods to deposit lithium on the surface, the invention uses mechanical powder mixing to distribute lithium uniformly throughout the active material. This substitution achieves better uniformity and reduces manufacturing complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If conventional electrochemical pre-lithiation method is used, then lithium is deposited on active material surface, but productivity is reduced

Engineering Contradiction:

Improvelithium contentVSAvoidmanufacturing efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-mixing the active material with lithium metal powder before electrode fabrication. This allows lithium to be uniformly distributed throughout the active material matrix from the outset, rather than attempting to deposit it later. The pre-mixed powder is then formed into electrodes, ensuring homogeneous lithium distribution throughout the electrode structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the electrochemical deposition system with a mechanical mixing system. Instead of using electrochemical methods to deposit lithium on the surface, the invention uses mechanical powder mixing to distribute lithium uniformly throughout the active material. This substitution achieves better uniformity and reduces manufacturing complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If SEI layer is formed during initial charging and discharging, then activation process occurs, but irreversible capacity loss occurs and electrolyte is exhausted

Engineering Contradiction:

Improveactivation processVSAvoidcapacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by pre-mixing the active material with lithium metal powder before electrode fabrication. This allows lithium to be uniformly distributed throughout the active material matrix from the outset, rather than attempting to deposit it later. The pre-mixed powder is then formed into electrodes, ensuring homogeneous lithium distribution throughout the electrode structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of lithium content by adding excess lithium through pre-mixing with lithium metal powder. This compensates for the lithium that will be irreversibly consumed during SEI layer formation, ensuring that sufficient lithium remains to maintain high capacity throughout the battery's operational life.

Inventive Principle:

Principle #35Parameter changes

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 method enhances battery capacity and initial efficiency by uniformly distributing lithium, reducing irreversible capacity loss, and simplifying the manufacturing process while maintaining cost-effectiveness.

Implementation Method 1

a pre-lithiation process in which a powder mixture of a negative electrode active material, a solid electrolyte particle, and a conductive agent contacts lithium metal

Methodology Applied

Scientific EffectIon transfer: Diffusion

Data Source

PatentUS12463199B2Method of pre-lithiating negative electrode for all-solid-state secondary batteries and secondary battery using the same

Publication Date: 2025.11.04 LG ENERGY SOLUTION LTD

AI summary

An all-solid-state secondary battery according to the present invention includes a positive electrode, a negative electrode, and a solid electrolyte formed between the positive electrode and the negative electrode, wherein the negative electrode is formed through a pre-lithiation process in which a powder mixture configured to form the negative electrode contacts lithium metal before battery assembly. Irreversible capacity is removed through the pre-lithiation process, whereby initial efficiency of the battery is improved, and the process is simplified, whereby mass production is possible and cost is reduced.