Garnet Solid Electrolyte Interphase for Dendrite-Free Li Contact
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Solution Overview
Problem
Solid-state lithium metal batteries face challenges with interfacial compatibility and lithium dendrite formation due to the solid nature and surface impurities of solid electrolytes, leading to high interfacial impedance and potential internal short circuits.
Innovation Solution
A modified garnet-type solid electrolyte with a three-dimensional crosslinking structure formed by a modification layer comprising strongly acidic and weakly acidic lithium salts, applied through an acid-salt treatment process, enhances interfacial compatibility and inhibits lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used to improve battery safety and minimize lithium dendrite growth, then battery safety is improved, but interfacial impedance increases and worsens during cycling
Solution Approach 1:
An artificial solid electrolyte interphase (SEI) layer is introduced as an intermediary between the lithium metal anode and the solid electrolyte. This modification layer comprises a strongly acidic lithium salt (e.g., lithium chloride, lithium perchlorate) and a weakly acidic lithium salt (e.g., lithium fluoride, lithium acetate) in a molar ratio of 1:1 to 10:1. The modification layer serves as a mediator that improves interfacial compatibility, reduces interfacial impedance, and prevents direct contact between the lithium anode and solid electrolyte, thereby eliminating polarization during cycling while maintaining battery safety.
2Quantity of substance
If lithium metal is used to replace graphite anode to increase energy density, then energy density is improved, but lithium dendrite formation occurs leading to internal short circuits
Solution Approach 1:
The artificial SEI modification layer is applied in advance to the lithium metal anode surface before assembly into the solid-state battery. This pre-formed protective layer prevents lithium dendrite formation by providing a uniform interface that guides uniform lithium ion deposition. The modification layer comprises strongly acidic and weakly acidic lithium salts that create a stable interphase, preventing uneven lithium deposition and dendrite growth along surface defects or grain boundaries of the electrolyte, thereby eliminating internal short circuit risks while maintaining high energy density.
3Object-affected harmful factors
If present strategies are used to address interfacial compatibility, then some improvement is achieved, but lithium dendrites still form at the electrolyte-Li anode interface and the process becomes complex and costly
Solution Approach 1:
The invention changes the chemical composition parameters of the interface by using a specific combination of strongly acidic lithium salt and weakly acidic lithium salt in a controlled molar ratio (1:1 to 10:1). This parameter change creates an artificial SEI layer with optimized properties that simultaneously improves interfacial compatibility and prevents lithium dendrite formation. The method is simple and cost-effective compared to present strategies, as it involves direct chemical treatment rather than complex multi-step processes.
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 modified electrolyte improves the contact area between the electrolyte and electrode, reduces interfacial impedance, and prevents lithium dendrite formation, resulting in stable battery performance and extended cycle life.
Implementation Method 1
possesses a three-dimensional crosslinking structure comprising at least one strongly acidic lithium salt and at least one weakly acidic lithium salt
Implementation Method 2
chemically treating at least one side of the garnet-type solid electrolyte with the mixed solution; and forming a modification layer on the at least one side
Data Source
AI summary
A modified garnet-type solid electrolyte, includes: a garnet-type solid electrolyte; a modification layer, such that the modification layer is formed on at least one side of the garnet-type solid electrolyte, and possesses a three-dimensional crosslinking structure comprising at least one strongly acidic lithium salt and at least one weakly acidic lithium salt. A method of forming a modified garnet-type solid electrolyte, includes: exposing a garnet-type solid electrolyte in air to form a pre-passivation layer; mixing solutions of strong acid and weakly acidic salt to form a mixed solution; chemically treating at least one side of the garnet-type solid electrolyte with the mixed solution; and forming a modification layer on the at least one side of the garnet-type solid electrolyte.