Liquid-Phase Oxide Coating for Silicon Anode Cycle Stability
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Solution Overview
Problem
Existing lithium-ion secondary batteries using silicon or tin as anode active materials face issues with charge-discharge efficiency due to electrolyte decomposition and insufficient cycle characteristics, particularly with coating films formed by air oxidation or vapor-phase methods.
Innovation Solution
A lithium-ion battery anode with an oxide-containing film formed by a liquid-phase method on the surface of anode active material particles, using silicon, germanium, or tin oxides, and optionally halides, to enhance chemical stability and charge-discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating film of silicon oxide is formed by air oxidation or vapor-phase method, then the anode active material surface is covered, but the coating film properties are poor or the particles are not sufficiently covered
Solution Approach 1:
The invention changes the formation method parameter from air oxidation or vapor-phase method to liquid-phase method. This parameter change enables uniform coverage of anode active material particles with oxide-containing film, resolving the issue of poor coating uniformity while maintaining protective function and improving cycle characteristics
Solution Approach 2:
The invention introduces a liquid-phase method as an intermediary process between the anode active material particles and the oxide-containing film formation. This intermediary approach allows for better control and uniformity in film deposition compared to direct air oxidation or vapor-phase methods, achieving sufficient particle coverage
2Stability of the object's composition
If the thickness of the coating film of silicon oxide is increased, then the chemical stability is improved, but the reaction resistance is increased
Solution Approach 1:
The invention changes the film formation method to liquid-phase method, which enables achieving adequate chemical stability with optimized film thickness. The liquid-phase method provides better control over film deposition, allowing formation of sufficiently thin yet effective oxide-containing films that protect the particles without creating excessive reaction resistance
Solution Approach 2:
The invention applies oxide-containing film selectively on the surface region of anode active material particles that contacts the electrolyte. This local application ensures chemical stability at the electrolyte interface while minimizing film thickness overall, thereby reducing reaction resistance compared to uniform thick coating
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 liquid-phase method ensures uniform coverage of the anode active material particles, improving chemical stability and charge-discharge efficiency, and allows for easier manufacturing compared to vapor-phase methods.
Implementation Method 1
the oxide-containing film is formed by a liquid-phase method
Implementation Method 2
an oxide-containing film including an oxide of at least one kind selected from the group consisting of silicon, germanium and tin
Data Source
AI summary
A battery including an anode with an anode active material layer that includes anode active material particles made of an anode active material including at least one of silicon and tin as an element. An oxide-containing film including an oxide of at least one kind selected from the group consisting of silicon, germanium and tin is formed in a region of the surface of each anode active material particle in contact with an electrolytic solution by a liquid-phase method such as a liquid-phase deposition method. The region in contact with the electrolytic solution of the surface of each anode active material particle is covered with the oxide-containing film. The thickness of the oxide-containing film is preferably within a range from 0.1 nm to 500 nm both inclusive.