Solid-State Battery SEI Layer for Dendrite-Resistant Lithium Anodes
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Solution Overview
Problem
Conventional solid-state batteries face challenges with inadequate energy density and cycle property, primarily due to dendrite formation on the negative electrode, which leads to short-circuiting and reduced capacity.
Innovation Solution
A method for producing a solid-state battery involving a negative electrode without an active material, where a solid electrolyte interface layer comprising lithium-containing organic and inorganic compounds is formed on the negative electrode surface before assembly, suppressing dendrite growth and enhancing cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is deposited on the negative electrode surface to increase energy density, then energy density is improved, but dendrites form during repeated charging and discharging leading to short-circuiting and reduced capacity
Solution Approach 1:
The patent applies preliminary action by forming a solid electrolyte interface (SEI) layer on the negative electrode surface before lithium metal deposition occurs during battery operation. This SEI layer is created through a preliminary electrochemical process that deposits a controlled layer of lithium-containing compounds, which then serves as a protective barrier during subsequent charging and discharging cycles, preventing dendrite formation while allowing ionic conductivity.
2Reliability
If physical pressure is applied to suppress dendrite growth during lithium metal precipitation, then cycle property is improved, but the weight and volume of the battery increase
Solution Approach 1:
The patent replaces the mechanical pressure system with a chemical/ electrochemical system. Instead of applying continuous mechanical pressure to suppress dendrites, the invention uses electrochemical processes to form a SEI layer that inherently suppresses dendrite growth through its ionic conductivity properties and structural characteristics, thereby eliminating the need for mechanical pressure application mechanisms.
3Quantity of substance
If an ultrathin lithium metal anode is used to achieve high energy density, then energy density is improved, but the battery becomes more sensitive to dendrite formation and short-circuiting
Solution Approach 1:
The patent introduces an intermediary SEI layer between the lithium metal anode and the electrolyte. This intermediary layer acts as a buffer that prevents direct contact and interaction between the lithium metal and the electrolyte, thereby suppressing dendrite formation and short-circuiting while maintaining the high energy density benefits of the ultrathin lithium metal anode.
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 approach results in a solid-state battery with improved energy density and cycle property, as the controlled SEI layer prevents dendrite formation, reducing the risk of short-circuiting and maintaining battery capacity over repeated charge-discharge cycles.
Implementation Method 1
forming, on at least one surface of the negative electrode, a solid electrolyte interface layer comprising a lithium-containing organic compound and a lithium-containing inorganic compound by immersing the negative electrode in a layer forming solution comprising a lithium salt and a precursor and thereafter causing a reduction reaction on the surface of the negative electrode
Data Source
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AI summary
The present invention provides a solid-state battery with high energy density and excellent cycle property, and a production method therefor. The production method for this solid-state battery 100, which contains a positive electrode 110, a solid electrolyte 120, and a negative electrode 140, comprises the steps of: preparing a negative electrode 140 that is free of a negative-electrode active material; and forming, on at least one surface of the negative electrode 140, a solid electrolyte interface layer 130 including a lithium-containing organic compound and a lithium-containing inorganic compound by immersing the negative electrode 140 in a layer forming solution containing a lithium salt and a precursor and thereafter causing a reduction reaction on the surface of the negative electrode 140.