Anode Active Material Prelithiation With Molten Alkali Metal

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Solution Overview

Problem

Existing methods for pre-lithiation of silicon oxide anode materials in lithium-ion batteries face challenges due to particle size mismatch between lithium powders and silicon oxide particles, leading to poor homogeneity and mechanical strength issues.

Innovation Solution

A method involving continuous mixing of anode material particles with molten alkali metals in a reaction chamber, followed by heat treatment in inert and fluorine-containing atmospheres to achieve homogenization and passivation, resulting in alkali metal-containing anode material particles with improved properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium powders are used for pre-lithiation of silicon oxide anode materials, then the initial coulombic efficiency is improved, but the homogeneity of lithium distribution is poor due to particle size mismatch

Engineering Contradiction:

Improveinitial coulombic efficiencyVSAvoidhomogeneity of lithium distribution

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of lithium from solid powder to molten liquid by heating above its melting point (150-200°C). This phase change enables lithium to flow and distribute uniformly throughout the silicon oxide particles, resolving the particle size mismatch issue while maintaining the pre-lithiation effect that improves initial coulombic efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a molten alkali metal as an intermediary medium that facilitates uniform lithium distribution. The molten state acts as a carrier that can penetrate and distribute lithium evenly throughout the anode material particles, solving the homogeneity problem caused by solid powder particle size mismatch

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If pre-lithiation is performed to compensate for irreversible capacity loss, then the reversible charging and discharging cycle capacity is improved, but the mechanical strength of anode particles deteriorates

Engineering Contradiction:

Improvereversible charging and discharging cycle capacityVSAvoidmechanical strength of anode particles

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The patent performs the molten lithium treatment in an inert atmosphere (argon or nitrogen) to prevent oxidation and degradation of the anode particles. This controlled environment protects the mechanical integrity of the particles while still allowing the beneficial pre-lithiation effect to occur, thus maintaining both cycle capacity and mechanical strength

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent utilizes the phase transition of lithium from solid to liquid and back to solid. The molten phase allows for gentle, uniform distribution without mechanical stress, and the subsequent solidification occurs in-situ within the particle structure, preserving mechanical strength while achieving the desired pre-lithiation effect

Inventive Principle:

Principle #36Phase transitions

3Quantity of substance

If solid lithium powder is mixed with silicon oxide particles, then pre-lithiation is achieved, but the mixing homogeneity is poor due to significant particle size difference

Engineering Contradiction:

Improveactive lithium contentVSAvoidmixing homogeneity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes lithium from solid powder to molten liquid state, fundamentally altering its physical properties. The molten lithium can flow and distribute uniformly throughout the silicon oxide particles regardless of size differences, achieving both high active lithium content and excellent mixing homogeneity that solid powder cannot provide

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

The method achieves enhanced initial coulombic efficiency and cyclic stability of lithium-ion batteries, with the produced anode materials exhibiting improved mechanical strength and capacity retention.

Implementation Method 1

heat the anode material particles mixed with the alkali metal source to a reaction temperature higher than a melting point of the alkali metal source

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

heat the plurality of alkali metal-containing anode material particles to a first temperature for a first period of time to homogenize the plurality of alkali metal-containing anode material particles

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

heat the homogenized alkali metal-containing anode material particles to a second temperature for a second period of time to passivate the homogenized alkali metal-containing anode material particles

Methodology Applied

Scientific EffectPassivation:

Data Source

PatentUS12322796B2Method of manufacturing anode active material

Publication Date: 2025.06.03 BLUE STAR ADVANCED MATERIALS CO LTD

AI summary

A method of manufacturing an anode active material is to dope a plurality of anode material particles with alkali metal by use of molten alkali metal to obtain a plurality of alkali-metal-containing anode material particles. The method of the invention is also to perform a homogenization process and a passivation process on the alkali metal-containing anode material particles to obtain a plurality of passivated and homogenized alkali-metal-containing anode material particles serving as the anode active material.