Solid Electrolyte-Coated Silicon Anode for PTFE Side-Reaction Suppression

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Solution Overview

Problem

Conventional dry processes using polytetrafluoroethylene (PTFE) binders for silicon anode electrodes in solid-state batteries suffer from side reactions that reduce battery performance due to the consumption of active lithium, leading to low initial columbic efficiency and poor capacity.

Innovation Solution

Coating silicon anode active material particles with a solid electrolyte, such as sulfide-based electrolytes, and using a fibrillating binder like PTFE to form a flexible, continuous dry film that inhibits side reactions and enhances lithium-ion transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If PTFE binder is used in silicon anode electrodes, then electrode flexibility and structural integrity are improved, but side reactions occur that consume active lithium and reduce battery performance

Engineering Contradiction:

Improvestructural integrityVSAvoidbattery performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

A solid electrolyte coating layer is introduced as an intermediary between the silicon anode active material particles and the PTFE binder. This coating layer prevents direct contact and side reactions between LixSi and PTFE, eliminating the harmful interaction while maintaining the structural benefits of the PTFE binder. The solid electrolyte acts as a protective barrier that allows ionic transport without enabling parasitic reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The anode electrode is designed as a composite structure with three components: silicon anode active material particles, solid electrolyte coating layer, and PTFE binder. This composite approach combines the high capacity of silicon with the flexibility of PTFE while using the solid electrolyte to prevent harmful side reactions, achieving both structural integrity and battery performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If solid electrolyte coating is applied to anode active material particles, then side reactions are prevented and columbic efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveinitial columbic efficiencyVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The solid electrolyte coating application is combined with the existing electrode manufacturing process. The coating is applied to the anode active material particles before mixing with the PTFE binder and forming the electrode, integrating the protective coating step into the standard production workflow rather than adding a separate, complex post-processing step.

Inventive Principle:

Principle #5Merging (Combining)

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 solution results in high initial columbic efficiency and stable cycling capacity by preventing side reactions between LixSi and PTFE, improving the overall performance of the anode electrodes.

Implementation Method 1

enhances lithium-ion transport

Methodology Applied

Scientific EffectLithium-ion transport: Ion Exchange

Implementation Method 2

A fibrillating binder like PTFE to form a flexible, continuous dry film

Methodology Applied

Scientific EffectFibrillation:

Data Source

PatentUS20250239600A1Silicon anode electrode with active material particles coated with solid electrolyte for solid-state battery cells

Publication Date: 2025.07.24 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An anode electrode for a battery cell includes an anode active material layer. The anode active material layer includes an anode active material and an outer coating layer covering at least a portion of an outer surface of particles of the anode active material layer. The outer coating layer includes a solid electrolyte and a fibrillating binder.