Solid-State Battery Anode Interlayer for Uniform Lithium Deposition

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Solution Overview

Problem

Existing all-solid secondary batteries face issues with short circuits and reduced lifetime due to non-uniform lithium metal deposition and interfacial instability between the anode and solid electrolyte, leading to cracks and poor performance.

Innovation Solution

An anode-solid electrolyte sub-assembly is introduced, comprising an interlayer with a composite of a first metal material and lithium ion conductor, and a first anode active material layer with lithium metal or alloy, where the metal material has a controlled particle size to maintain structural integrity during charging and discharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal or alloy is used in the anode active material layer, then high energy density is achieved, but non-uniform lithium deposition causes short circuits and reduced lifetime

Engineering Contradiction:

Improveenergy densityVSAvoidshort circuit prevention and lifetime

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A buffer layer comprising a metal material (such as tin, silicon, germanium, or their alloys) is introduced between the lithium metal anode and the solid electrolyte. This buffer layer acts as an intermediary that promotes uniform lithium ion distribution during charging and discharging, preventing direct contact between lithium metal and solid electrolyte, thereby eliminating short circuits while maintaining high energy density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical and chemical parameters of the anode structure by controlling the particle size of lithium metal (1-50 μm) and metal material (0.1-300 nm), adjusting their compositional ratios, and optimizing the buffer layer thickness (1-50 nm). These parameter changes enable uniform lithium deposition and improve battery lifetime while preserving high energy density.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a simple metal active material layer is formed for stable interface formation, then interface stability is improved, but high-rate characteristics and lifetime characteristics remain insufficient

Engineering Contradiction:

Improveinterface stabilityVSAvoidhigh-rate characteristics and lifetime

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention creates a composite anode structure consisting of lithium metal particles, metal material particles (tin, silicon, germanium or their alloys), and a buffer layer. This composite material system combines the high capacity of lithium metal with the structural stability of metal materials and the protective function of the buffer layer, achieving both interface stability and improved high-rate characteristics.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The buffer layer is applied locally at the critical interface between the lithium metal anode and solid electrolyte, providing targeted protection and lithium ion distribution control where it is most needed. This localized intervention stabilizes the interface without compromising the overall high-rate performance and lifetime characteristics of the battery.

Inventive Principle:

Principle #3Local quality

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 enhances the durability and interfacial stability of the battery, preventing short circuits and improving high-rate characteristics and lifetime performance.

Implementation Method 1

the interlayer includes a composite comprising a first metal material and a lithium ion conductor

Methodology Applied

Scientific EffectIon conduction: Fast Ion Conductor

Implementation Method 2

the first metal material includes a first metal that forms an alloy or a compound with lithium

Methodology Applied

Scientific EffectAlloy formation: Chemical Bonding

Implementation Method 3

the first anode active material layer including a lithium metal, a lithium alloy, or a combination thereof

Methodology Applied

Scientific EffectElectrochemical reaction: Redox Reactions

Data Source

PatentUS12573620B2Anode for all-solid secondary battery, all-solid secondary battery including the same, and manufacturing method thereof

Publication Date: 2026.03.10 SAMSUNG ELECTRONICS CO LTD

AI summary

An anode-solid electrolyte sub-assembly for an all-solid secondary battery, the anode-solid electrolyte sub-assembly including: an anode current collector; an anode material layer on the anode current collector; and a solid electrolyte on the anode material layer and opposite the current collector, wherein the anode material layer includes an interlayer, which contacts the solid electrolyte and includes a composite including a first metal material; and a first anode active material layer on the interlayer and opposite the anode current collector, the first anode active material layer including a lithium metal, a lithium alloy, or a combination thereof, wherein the lithium metal or the lithium alloy have a particle size greater than the particle size of the first metal material.