Negative Electrode Pre-Lithiation with Halogenated Carbonate SEI

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Solution Overview

Problem

Existing pre-lithiation methods for negative electrodes in secondary batteries result in reduced capacity and cycle lifespan due to redox reactions with oxygen or carbon dioxide, leading to insufficient coulomb efficiency and oxidation resistance.

Innovation Solution

A method involving the use of a pre-lithiation solution containing an organic carbonate compound substituted with halogen to form an SEI film with LiF and Li2CO3, preventing electron transfer and enhancing oxidation resistance by charging the negative electrode with a constant voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If pre-lithiation is performed by allowing lithium metal to directly contact the negative electrode or by electrochemical charging, then the negative electrode is pre-lithiated to compensate for passive film formation, but the pre-lithiated negative electrode undergoes redox reactions with oxygen or carbon dioxide in the air, consuming electrons and lithium ions, thereby reducing coulomb efficiency and battery lifespan

Engineering Contradiction:

Improvelithium ion contentVSAvoidcoulomb efficiency

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a protective coating layer as an intermediary between the pre-lithiated negative electrode and the external environment (oxygen and carbon dioxide). This coating prevents direct contact and redox reactions, thereby preserving the coulomb efficiency while maintaining the beneficial lithium ion content introduced through pre-lithiation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an inert protective environment around the pre-lithiated negative electrode through the coating layer, which acts as a barrier against reactive gases (oxygen and carbon dioxide). This inert environment prevents unwanted redox reactions and maintains the stability of the pre-lithiated state.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Duration of action of stationary object

If pre-lithiation is performed to compensate for lithium ion consumption during passive film formation, then cycle lifespan is improved, but oxidation resistance is insufficient due to redox reactions with oxygen or carbon dioxide, leading to capacity reduction

Engineering Contradiction:

Improvecycle lifespanVSAvoidoxidation resistance

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The protective coating serves as an intermediary barrier that shields the pre-lithiated negative electrode from oxidative harm. This allows the electrode to maintain its improved cycle lifespan while gaining the additional protection needed to resist oxidation from environmental gases.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies protective coating before the electrode is exposed to harmful environmental conditions during storage or assembly. This beforehand cushioning prevents oxidation damage before it can occur, preserving both the capacity and cycle lifespan benefits of pre-lithiation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

Prevents redox reactions with oxygen or carbon dioxide, maintaining initial coulomb efficiency and improving cycle characteristics by forming an SEI film with LiF and Li2CO3, thereby stabilizing the negative electrode.

Implementation Method 1

pre-lithiating the negative electrode by charging the pre-lithiation cell with a constant voltage to form a pre-lithiated negative electrode, wherein the pre-lithiation solution contains 3 volume % to 30 volume % of an organic carbonate compound substituted with halogen

Methodology Applied

Scientific EffectSEI film formation:

Implementation Method 2

pre-lithiating the negative electrode by charging the pre-lithiation cell with a constant voltage

Methodology Applied

Scientific EffectElectrochemical charging:

Implementation Method 3

Methodology Applied

Scientific EffectRedox reaction prevention: Redox Reactions

Implementation Method 4

enhancing the oxidation resistance of the negative electrode during the pre-lithiation process

Methodology Applied

Scientific EffectOxidation resistance enhancement: Oxidation

Data Source

PatentUS12519097B2Negative electrode pre-lithiation method

Publication Date: 2026.01.06 LG ENERGY SOLUTION LTD

AI summary

A negative electrode pre-lithiation method comprising the steps of: manufacturing a negative electrode by forming, on a negative electrode current collector, a negative electrode active material layer comprising a negative electrode active material. Then, manufacturing a pre-lithiation cell, which comprises the negative electrode and a lithium metal counter electrode, and impregnating the pre-lithiation cell with a pre-lithiation solution; and charging the pre-lithiation cell with a constant voltage to form a pre-lithiated negative electrode. The pre-lithiation solution comprises 3 vol % to 30 vol % of an organic carbonate compound substituted with halogen.