Metal Anode SEI Layer for Uniform Lithium Plating
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Solution Overview
Problem
Current lithium-ion batteries face limitations due to uneven lithium plating at lithium metal anodes, leading to dendrite formation, short-circuiting, and reduced battery capacity, which hinders their adoption in high-performance applications like electric vehicles.
Innovation Solution
A rechargeable battery design featuring a metal anode with a solid electrolyte interphase (SEI) layer composed of a specific chemical composition (MαBβCγNδFεXζOη) that suppresses dendrite formation, facilitates even lithium plating, and extends battery life by limiting electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal anodes are used to achieve high theoretical specific capacity (3860 mAh/g), then battery energy density is improved, but uneven lithium plating occurs leading to dendrite formation and short-circuiting
Solution Approach 1:
A solid electrolyte interphase (SEI) layer is introduced as an intermediary protective coating on the lithium metal anode surface. This SEI layer acts as a mediator between the lithium metal and the electrolyte, suppressing dendrite formation while allowing lithium ion transport. The layer comprises specific chemical compositions (LiF, Li2SiO3, Li3PO4, Li2SiO2N, Li3PO2N, Li2SiO2F, Li3PO2F, Li4SiO2N, Li4SiO2F, Li3SiO2N, Li3SiO2F, Li2SiO2X, Li3PO2X, Li4SiO2X, Li2SiO2NX, Li2SiO2FX, where X = Cl, Br, or I) that provide both protection and ionic conductivity.
Solution Approach 2:
The invention changes the chemical composition parameters of the SEI layer by incorporating specific ratios of lithium compounds and halogen elements. The SEI layer composition is controlled to contain 1-50 atomic percent halogen (F, Cl, Br, or I), which modifies the electrochemical properties to suppress dendrite growth while maintaining high lithium ion conductivity for achieving the theoretical specific capacity of lithium metal.
2Quantity of substance
If lithium metal anodes are used to achieve high specific capacity, then battery energy density is improved, but battery safety deteriorates due to short-circuiting risks
Solution Approach 1:
The SEI layer serves as a protective intermediary that physically separates the lithium metal from direct contact with the electrolyte, preventing the harmful short-circuiting effect while maintaining ionic transport. This intermediary layer eliminates the direct harmful interaction between lithium metal and electrolyte that leads to short-circuits.
Solution Approach 2:
The invention converts the potentially harmful reaction between lithium metal and electrolyte into a beneficial protective SEI layer. The initial formation process transforms harmful electrolyte decomposition into a controlled formation of a protective coating that prevents future harmful effects while enabling safe operation at high capacity.
3Reliability
If conventional lithium-ion batteries with graphite anodes are used, then safety is maintained, but specific capacity is limited to 372 mAh/g
Solution Approach 1:
The SEI layer acts as a protective intermediary that enables the use of high-capacity lithium metal anodes by suppressing dendrite formation and short-circuiting, thereby achieving both high specific capacity (3860 mAh/g) and improved safety compared to conventional graphite anodes (372 mAh/g).
Solution Approach 2:
The invention changes the anode material parameter from graphite (372 mAh/g) to lithium metal (3860 mAh/g) while simultaneously modifying the interface conditions through the SEI layer to maintain safety, thus achieving both high capacity and safety.
4Quantity of substance
If lithium metal anodes are used, then specific capacity is improved, but electrolyte decomposition increases reducing battery life
Solution Approach 1:
The SEI layer serves as a protective barrier that reduces electrolyte decomposition by preventing direct contact between the electrolyte and lithium metal surface. This intermediary layer significantly reduces the loss of electrolyte substance while enabling the use of high-capacity lithium metal anodes.
Solution Approach 2:
The invention converts the harmful electrolyte decomposition process into a beneficial formation of a stable SEI layer. The initial electrolyte decomposition is controlled to form a protective coating that subsequently prevents further harmful decomposition, thereby extending battery life while maintaining high capacity.
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 SEI layer effectively prevents dendrite growth and enhances lithium plating uniformity, thereby improving battery safety and capacity retention, making lithium metal anodes more viable for high-performance applications.
Implementation Method 1
a solid electrolyte interphase (SEI) layer on a surface of the metal anode, wherein the SEI layer has a composition according to Formula (1)
Implementation Method 2
limits electrolyte decomposition, and extends battery life
Data Source
AI summary
A rechargeable battery has a metal anode with a solid electrolyte interphase (SEI) surface layer, a cathode with a halogen species integrated in a porous carbon material, an electrolyte with an organic solvent and a salt that is in contact with the anode and the cathode, and an oxidizing gas in contact with the electrolyte. The SEI layer has the composition MαBβCγNδFεXζOη, where M is a metal, B is boron, C is carbon, N is nitrogen, F is fluorine, X is a non-fluorine halogen species, and O is oxygen; α is a number in the range of 0.2-0.4, β is a number in the range of 0.0-0.1, γ is a number in the range of 0.15-0.25, δ is a number in the range of 0.0-0.02, ε is a number in the range of 0.0-0.1, ζ is a number in the range of 0.005-0.02, η is a number in the range of 0.40-0.60, and α, β, γ, δ, ε, ζ, and η are selected such that the sum of α+β+γ+δ+ε+ζ+η=1. The SEI surface layer on the metal anode suppresses the formation of dendrites, facilitates the even plating of lithium, limits electrolyte decomposition, and extends battery life.