Silicon-Anode Battery Electrolyte for High-Temperature Cycling
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Solution Overview
Problem
Conventional secondary batteries face challenges in achieving high energy density, long cycle life, and maintaining performance under high-temperature conditions due to the swelling of silicon-based negative active materials during charge-discharge cycles, which reduces electrochemical performance.
Innovation Solution
Incorporating ethylene carbonate (EC) and ethyl methyl carbonate (EMC) with specific weight ratios in the electrolyte, along with lithium hexafluorophosphate (LiPF6) and lithium bisfluorosulfonimide (LiFSI), to enhance the high-temperature storage and cycle performance of silicon-based secondary batteries, while using silicon-based materials as negative active materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon-based material is used as negative active material to improve energy density, then energy density is improved, but the silicon-based material swells during charge-discharge cycles causing electrochemical performance to deteriorate sharply
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by specifying precise weight ratios of EC (5-15%) and EMC (85-90%), which modifies the electrolyte's interaction with silicon-based materials during cycling, thereby suppressing swelling while maintaining high energy density
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple components (EC, EMC, and lithium salts) that work synergistically to address the swelling issue of silicon-based negative electrodes while preserving their high capacity benefits
2Ease of manufacture
If conventional electrolyte composition is used, then manufacturing simplicity is maintained, but high-temperature storage and cycle performance are poor
Solution Approach 1:
The patent optimizes the concentration parameters of electrolyte components (EC at 5-15% and EMC at 85-90% by weight) to achieve a balance between ease of preparation and superior high-temperature performance, allowing standard manufacturing processes to produce high-performance batteries
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 proposed solution effectively improves the high-temperature storage and cycle performance of secondary batteries, maintaining energy density and reducing gas production, thereby extending the battery's lifespan and efficiency.
Implementation Method 1
the organic solvent contains ethylene carbonate (EC) and ethyl methyl carbonate (EMC), a weight ratio of the ethylene carbonate (EC) in the organic solvent is less than or equal to 10%, and a weight ratio of the ethyl methyl carbonate (EMC) in the organic solvent is 80% to 95%
Data Source
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AI summary
The application provides a secondary battery and an apparatus including the same. The secondary battery includes a negative electrode plate and an electrolyte; the negative electrode plate includes a negative current collector and a negative electrode film disposed on at least one surface of the negative current collector and including a negative active material; and the electrolyte includes electrolyte salt and an organic solvent, where the negative active material includes a silicon-based material; and the organic solvent contains ethylene carbonate (EC) and ethyl methyl carbonate (EMC), a weight ratio of the ethylene carbonate (EC) in the organic solvent is less than or equal to 10%, and a weight ratio of the ethyl methyl carbonate (EMC) in the organic solvent is 70% to 95%. According to the application, the secondary battery and the apparatus including the same, in the premise of having a high energy density, can simultaneously have good high-temperature storage performance and high-temperature cycle performance.