Layered Silicon-Based Active Material Particles for Battery Ion Uptake

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Solution Overview

Problem

Existing silicon-based active material particles for lithium-ion secondary batteries have limited ion uptake ability, which affects the output characteristics of batteries.

Innovation Solution

Silicon-based active material particles with a layer structure are developed, where the oxygen element in silicon oxide reacts with lithium to form lithium silicate, enhancing lithium conductivity and ion uptake ability, and the method involves a laminated coating formation and scraping process to adjust the layer thickness and bonding force, improving pulverization properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional silicon-based active material particles without layer structure are used, then the structure is simple and easy to manufacture, but the ion uptake ability is limited

Engineering Contradiction:

Improveion uptake abilityVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The silicon-based active material particle is segmented into multiple layers with different compositions (silicon oxide layer, silicon-rich layer, and optional outer layer), creating a layered structure that facilitates ion uptake while maintaining manufacturability through controlled deposition processes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the particle are assigned different local qualities: the silicon oxide layer provides structural stability, the silicon-rich layer enhances lithium conductivity and ion uptake, and the outer layer protects against degradation, allowing each region to optimize its function

Inventive Principle:

Principle #3Local quality

2Reliability

If layer thickness is increased to improve ion uptake ability, then lithium conductivity is enhanced, but initial efficiency and capacity become undersized

Engineering Contradiction:

Improvelithium conductivityVSAvoidinitial efficiency and capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The layer thickness is precisely controlled within the range of 0.01-1 μm to optimize the balance between lithium conductivity (improved by thicker layers) and initial efficiency/capacity (maintained by limiting thickness), with the silicon-rich layer specifically designed to be 0.01-0.5 μm thick

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The silicon-rich layer is designed with sufficient thickness to provide the necessary lithium conductivity enhancement, but not excessively thick to avoid sacrificing initial capacity, achieving the optimal partial thickness for maximum benefit

Inventive Principle:

Principle #16Partial or excessive action

3Use of energy by moving object

If silicon-based active material precursor particles with layer structure are pulverized, then energy consumption is reduced, but the bonding force between layers must be controlled

Engineering Contradiction:

Improvepulverization energyVSAvoidbonding force between layers

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The bonding force between layers is dynamically controlled through deposition parameters to achieve optimal pulverization properties, allowing the layered structure to fracture at controlled interfaces during pulverization, reducing energy consumption while maintaining structural integrity for ion uptake

Inventive Principle:

Principle #15Dynamics

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 silicon-based active material particles with a layer structure exhibit superior ion uptake ability and improved output characteristics of lithium-ion secondary batteries, with enhanced pulverization properties and energy efficiency.

Implementation Method 1

the oxygen element (O) of the silicon oxide (SiOx) reacts with the lithium (Li) by charging to produce lithium silicate

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

a deposition step in which a silicon-based active material forming material is deposited on a substrate

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS20220416234A1Method for producing silicon-based active material particles and silicon-based active material precursor particles

Publication Date: 2022.12.29 OSAKA TITANIUM TECHNOLOGIES

AI summary

An object of the present invention is to provide active material particles excellent in ion uptake ability. The silicon-based active material particles according to the present invention comprise a layer structure. Here, the “silicon-based active material particles” are, for example, active material particles for forming a negative electrode of a lithium ion secondary battery. Examples of the active material particles for forming the negative electrode of the lithium ion secondary battery include so-called Si-based active materials such as silicon (Si), silicon oxide (SiOx), metal element-containing silicon oxide containing alkaline metal elements such as lithium (Li) and alkaline earth metal elements such as magnesium (Mg), silicon alloys. The thickness of the layer in the active material particles is preferably 1 μm or less. Here, the thickness of the layer is preferably 0.01 μm or more.