Anode-Free Lithium Secondary Battery Coating for Dendrite Control
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high energy density and maintaining excellent cycle characteristics due to the limitations of negative-electrode active materials, such as volume occupation and dendrite formation leading to short circuits and capacity reduction.
Innovation Solution
A lithium secondary battery design featuring a negative electrode without active materials, where the surface facing the positive electrode is coated with a compound containing an aromatic ring with bonded N, S, and O elements, and an electrolyte solution including a lithium salt and solvent represented by Formula (1), which enhances energy density and cycle performance by promoting lithium metal deposition and dissolution reversibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a negative electrode with active material (such as carbon material or lithium metal) is used, then the battery structure is stable, but the energy density is reduced due to volume and mass occupation by the active material
Solution Approach 1:
The invention extracts and removes the negative-electrode active material from the battery structure, using only a negative electrode current collector without traditional active materials like carbon or lithium metal. This extraction eliminates the volume and mass occupation caused by active materials while maintaining battery functionality through in-situ lithium metal formation during initial charging cycles
Solution Approach 2:
The invention performs preliminary action by forming a protective coating layer on the negative electrode current collector surface before battery operation. This coating layer, applied in advance, prevents dendrite formation and stabilizes lithium metal deposition during subsequent charge/discharge cycles, enabling the anode-free structure to function reliably
2Quantity of substance
If an anode-free negative electrode is used to improve energy density, then volume is reduced, but dendrite-like lithium metal forms during repeated charge/discharge causing short circuits and capacity reduction
Solution Approach 1:
The invention introduces a coating layer as an intermediary substance between the negative electrode current collector and the electrolyte solution. This intermediate layer mediates the interaction between lithium ions and the current collector, guiding uniform lithium metal deposition and preventing dendrite formation during charge/discharge cycles, thereby improving cycle reliability
Solution Approach 2:
The invention changes the surface parameters of the negative electrode by applying a coating layer with specific chemical composition and physical properties. This parameter change modifies the electrode surface characteristics to promote uniform lithium ion distribution and deposition, preventing the formation of dendritic structures that compromise cycle life
3Device complexity
If conventional electrolyte solutions are used with anode-free batteries, then the battery structure is simple, but the positive electrode material deteriorates during repeated charge/discharge
Solution Approach 1:
The coating layer on the negative electrode acts as an intermediary that stabilizes the electrochemical environment during charge/discharge cycles. This intermediate structure prevents direct harmful interactions between lithium metal and the positive electrode material, reducing deterioration while maintaining overall structural simplicity of the anode-free design
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 results in a lithium secondary battery with improved energy density and cycle characteristics, reducing dendrite growth and maintaining capacity over repeated charge/discharge cycles, while also suppressing positive electrode material deterioration.
Implementation Method 1
lithium secondary batteries which perform charge/discharge by transferring lithium ions between a positive electrode and a negative electrode
Implementation Method 2
metal particles are formed on a negative electrode current collector and transferred from the positive electrode, when the battery is charged, to form lithium metal on the negative electrode current collector in the negative electrode
Data Source
AI summary
The purpose of the present invention is to provide a lithium secondary battery having a high energy density and an excellent cycle characteristic. The present invention relates to a lithium secondary battery including a positive electrode, a negative electrode not having a negative-electrode active material, and an electrolyte solution, in which at least a part of a surface of the negative electrode facing the positive electrode is coated with a compound including an aromatic ring to which two or more elements selected from the group consisting of N, S, and O are each independently bonded, and the electrolyte solution contains a lithium salt and a solvent represented by Formula (1).