Secondary Battery Electrolyte Additives for Lithium Dendrite Suppression

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Solution Overview

Problem

The uncontrollable growth of lithium dendrites and instability of solid electrolyte interphase (SEI) films hinder the large-scale commercial application of lithium metal-based batteries due to issues like electrolyte decomposition, Li surface corrosion, and degradation of cathode materials, limiting their practical use in electric vehicles and energy storage systems.

Innovation Solution

A combination of a thiol compound and an aromatic Schiff base is used as additives in electrolytes, forming a protective layer on both the anode and cathode surfaces through self-assembly, inhibiting dendrite growth and promoting Li+ ion transport, thereby stabilizing the electrolyte and enhancing electrochemical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as anode electrode to achieve ultrahigh theoretical capacity, then energy density is improved, but lithium dendrite growth and SEI film instability occur causing safety and reliability issues

Engineering Contradiction:

Improveenergy densityVSAvoiddendrite growth control

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming a protective interfacial layer on the lithium metal surface using thiol compound and aromatic Schiff base additives before battery operation. This pre-formed layer prevents uncontrollable dendrite growth and stabilizes the SEI film, allowing lithium metal anodes to achieve their ultrahigh theoretical capacity (3860 mAh g−1) without the safety and reliability issues of dendrite formation and electrolyte decomposition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses thiol compound and aromatic Schiff base additives as intermediary substances that form a protective interfacial layer between the lithium metal anode and the electrolyte. This intermediary layer mediates the interaction between lithium metal and electrolyte, preventing direct contact that would cause dendrite growth and electrolyte decomposition, while still allowing Li+ ion transport for high energy density operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional electrolyte additives are used to form protective layers, then anode protection is improved, but cathode protection and simultaneous in-situ modification cannot be achieved

Engineering Contradiction:

Improveanode protectionVSAvoidsimultaneous electrode modification

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by designing thiol compound and aromatic Schiff base additives that perform multiple functions simultaneously: they form protective layers on both the lithium metal anode and cathode materials (such as NCM or LFP), preventing electrolyte decomposition at both electrodes. This multi-functional additive system enables simultaneous in-situ modification of both anode and cathode, overcoming the limitation of conventional single-function additives that only protect one electrode.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If highly fluorinated ether solvent is used to increase energy density, then energy density beyond 400 Wh kg−1 is achieved, but low solubility prevents large-scale application

Engineering Contradiction:

Improveenergy densityVSAvoidsolubility

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining highly fluorinated ether solvent with thiol compound and aromatic Schiff base additives to create a composite electrolyte system. The fluorinated ether provides high energy density (beyond 400 Wh kg−1) while the thiol and Schiff base additives improve solubility and form protective interfacial layers, enabling both high energy density and ease of manufacture through enhanced solubility and stability.

Inventive Principle:

Principle #40Composite materials

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 additive combination significantly inhibits lithium dendrite formation, stabilizes the electrolyte, and promotes fast Li+ ion diffusion, leading to improved cyclic stability and increased energy density in secondary batteries, with superior performance observed in Li|Li symmetric cells and full cells.

Implementation Method 1

forming a protective layer on both the anode and cathode surfaces through self-assembly

Methodology Applied

Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

promotes fast Li+ ion diffusion

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Data Source

PatentUS20260018668A1Additive combination for secondary battery electrolytes

Publication Date: 2026.01.15 INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE

AI summary

An additive combination for an electrolyte for a secondary battery is provided. The additive combination comprises a thiol compound and an aromatic Schiff base. An electrolyte for a secondary battery comprising a salt and this additive combination is also provided together with a method of manufacturing this electrolyte. A secondary battery comprising an anode, a cathode, and this electrolyte between the anode and the cathode is provided together with a method of manufacturing this battery. In this battery, at least one electrode surface bears a layer comprising the thiol compound and the aromatic Schiff base. Finally, an electrode having a surface layer comprising the thiol compound and the aromatic Schiff base is also provided together with a method for manufacturing such electrode.