Anode-Electrolyte Composition for Fast-Charging Cycle Stability
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Solution Overview
Problem
Existing electrochemical devices, such as lithium-ion batteries, face challenges in achieving high energy density, fast charging and discharging capabilities, and maintaining excellent electrochemical performance while optimizing the entire device.
Innovation Solution
The electrochemical device is designed with a specific configuration including a cathode, an anode with an anode current collector and an anode active material layer, and an electrolyte containing fluoroethylene carbonate (FEC). The device meets a specific relationship between the specific surface area of the anode active material, the content of FEC, and the weight of the anode active material, which facilitates better formation of a solid electrolyte interface (SEI) film and improves cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the anode active material has high specific surface area to improve kinetic performance, then fast charging and discharging capability is improved, but side reaction products increase and cycle performance deteriorates
Solution Approach 1:
The patent optimizes the specific surface area parameter of the anode active material to a specific range (0.8-2.5 m²/g) to balance kinetic performance and cycle stability. This parameter optimization resolves the contradiction by finding the optimal point where charging/discharging capability is sufficiently fast while side reactions are controlled.
Solution Approach 2:
The patent uses a composite anode structure combining anode active material with conductive carbon material. This composite approach improves kinetic performance through the conductive network while the controlled specific surface area of the active material prevents excessive side reactions, thus resolving the contradiction between speed and reliability.
2Reliability
If the content of fluoroethylene carbonate (FEC) is increased to improve SEI film stability, then cycle performance is improved, but manufacturing cost and electrolyte composition complexity increase
Solution Approach 1:
The patent optimizes the FEC content parameter within a specific range (0.02-0.3 g/Ah) rather than using excessive amounts. This controlled parameter optimization achieves sufficient SEI film stability while avoiding the need for complex electrolyte formulations, thus resolving the contradiction between reliability and device complexity.
3Speed
If the anode active material layer has high porosity to improve electrolyte infiltration, then kinetic performance is improved, but energy density decreases
Solution Approach 1:
The patent optimizes the porosity parameter of the anode active material layer to a specific range that balances electrolyte infiltration and energy density. This parameter optimization ensures sufficient kinetic performance while maintaining high active material content, thus resolving the contradiction between speed and quantity of substance.
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 enhances the cycle performance and kinetic performance of the electrochemical device by improving the stability of the SEI film, reducing side reaction products, and optimizing electrolyte infiltration, thereby achieving better energy storage capabilities.
Implementation Method 1
the electrolyte includes fluoroethylene carbonate (FEC)... facilitates better formation of a solid electrolyte interface (SEI) film
Implementation Method 2
Electrochemical devices, such as lithium-ion batteries... high energy density, long cycle life... fast charging and discharging capability
Data Source
AI summary
An electrochemical device, including a cathode, an anode and an electrolyte. The anode includes an anode current collector and an anode active material disposed on the anode current collector, the electrolyte includes fluoroethylene carbonate, and the electrochemical device meets the following relationship: 17.55≤K1−K2−1.63K32+11.27K3≤20.80, where K1 represents a specific surface area value of the unit mass of the anode active material (in m2/g), and 1.0≤K1≤2.0; K2 represents a content value of the fluoroethylene carbonate required by per Ah capacity (in g/Ah), and 0.05≤K2≤0.25; and K3 represents a weight value of the anode active material required by per Ah capacity (in g/Ah).