Composite Electrode With Artificial Passive Film And Dual Electrolyte Layers
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Solution Overview
Problem
Lithium ion secondary batteries face safety concerns due to the volatile nature of liquid electrolytes and high resistance issues with solid electrolytes, leading to instability and potential thermal runaway.
Innovation Solution
A composite electrode material structure is introduced, featuring an active material coated with an artificial passive film, a middle layer with a higher concentration of deformable electrolyte, and an outer layer with a higher concentration of undeformable electrolyte, reducing organic solvent usage and enhancing ion conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If liquid electrolyte is used, then ionic conductivity is high, but safety deteriorates due to volatility and flammability
Solution Approach 1:
The patent employs a composite electrode structure consisting of an active material core, an artificial passive film layer, and a dual electrolyte system (combining solid and gel/liquid electrolytes). This composite approach allows the system to achieve both high ionic conductivity from the liquid/gel phase and improved safety from the solid phase and protective artificial passive film, thereby resolving the contradiction between conductivity and safety
2Object-affected harmful factors
If solid electrolyte is used, then safety improves, but charge transfer resistance increases due to poor contact area
Solution Approach 1:
The patent applies local quality by creating a dual electrolyte system where the composition varies by location: the inner layer adjacent to the active material contains primarily solid electrolyte for safety and stability, while the outer layer contains gel/liquid electrolyte for low resistance and high ionic conductivity. This spatial differentiation of electrolyte properties resolves the contradiction between safety and charge transfer efficiency
Solution Approach 2:
The composite electrode structure combines solid electrolyte particles with gel/liquid electrolyte in a matrix, creating a material that exhibits both the safety advantages of solid electrolytes and the high ionic conductivity of liquid/gel electrolytes, thereby reducing charge transfer resistance while maintaining safety
3Loss of substance
If artificial passive film is added, then lithium ion consumption is reduced, but device complexity increases
Solution Approach 1:
The artificial passive film is formed on the active material core before the electrolyte layers are applied, creating a pre-protective barrier that prevents direct contact between the electrolyte and active material. This preliminary protective action reduces lithium ion consumption from the outset without requiring complex operational controls
Solution Approach 2:
The patent modifies the surface properties of the active material by coating it with an artificial passive film, changing the interface characteristics between the active material and electrolyte. This parameter change (surface coating) effectively reduces unwanted lithium ion consumption while adding only a thin protective layer, minimizing the increase in structural complexity
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
This configuration prevents unnecessary lithium ion consumption, improves safety, and enhances ion conduction by minimizing charge transfer resistance and contact area issues, while maintaining high chemical stability.
Implementation Method 1
The artificial passive film (APF) is used to efficiently prevent the liquid electrolytes to contact with the active materials
Implementation Method 2
the content of the deformable electrolyte is more than a content of the undeformable electrolyte in middle layer
Implementation Method 3
the content of the undeformable electrolyte is more than the content of the deformable electrolyte in outer layer
Data Source
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AI summary
The invention discloses a composite electrode materials with improved structure. The composite electrode materials of this invention includes at least one active material. The active material is coated an artificial passive film on its surface to effectively prevent or reduce the contact of the electrolyte and the active material to avoid unnecessary consumption of Li-ions. Also, there have a middle layer and an outer layer outside of the artificial passive film. Both of the middle layer and the outer layer are composed of the deformable electrolyte and the undeformable electrolyte, but with different concentration ratios. Therefore, the better ion-conduction is achieved with reduced charge-transfer resistance and reduced usage amount of organic solvent.