LiPO2F2 Electrolyte Tuning for Low-Impedance LFP Batteries
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Solution Overview
Problem
Lithium-ion batteries, particularly those with lithium iron phosphate positive electrodes, face challenges in achieving improved cycling performance, high-temperature storage performance, and kinetic performance while maintaining low cost and safety.
Innovation Solution
Incorporating specific additives such as LiPO2F2 in the electrolyte, along with vinylene carbonate and other compounds like fluoroethylene carbonate, to optimize the active specific surface area and composition of the positive electrode active material, which enhances the electrochemical device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium iron phosphate positive electrode material is used, then safety performance and service life are improved, but cycling performance and kinetic performance remain insufficient for high-demand applications
Solution Approach 1:
The patent modifies the electrolyte composition by introducing LiPO2F2 additive at specific weight percentages (0.01-5%) to change the electrochemical parameters of the system. This parameter change enables the lithium iron phosphate battery to achieve both high safety performance and improved cycling performance, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent creates a composite electrolyte system combining LiPO2F2 additive with conventional electrolyte components (cyclic carbonates and chain carbonates). This composite approach synergistically enhances both the safety characteristics and the kinetic performance of the lithium iron phosphate battery, allowing simultaneous improvement of reliability and productivity.
2Duration of action of stationary object
If electrolyte optimization is performed to improve life and safety performance, then service life and safety are enhanced, but cost may increase
Solution Approach 1:
The patent applies partial action by using a small but optimized concentration of LiPO2F2 additive (0.01-5% by weight). This partial addition is sufficient to achieve significant improvements in service life and safety performance without requiring excessive amounts that would substantially increase manufacturing cost, thus resolving the contradiction between duration and ease of manufacture.
3Productivity
If higher requirements are imposed on battery performance for traction and energy storage, then application performance is improved, but achieving these requirements at low cost becomes challenging
Solution Approach 1:
The patent achieves high application performance for traction and energy storage applications by optimizing the electrolyte composition parameter - specifically the weight percentage of LiPO2F2 additive. This parameter optimization delivers improved cycling performance, high-temperature storage performance, and kinetic performance while maintaining cost-effectiveness through controlled additive concentration.
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 significantly improves cycling performance, high-temperature storage performance, and kinetic performance of lithium-ion batteries, ensuring better energy efficiency and safety without increasing costs.
Implementation Method 1
an electrolyte, where the electrolyte contains an additive A, the additive A contains LiPO2F2
Implementation Method 2
a positive electrode active material layer provided on the current collector, the positive electrode active material layer includes a positive electrode active material
Data Source
AI summary
An electrochemical device includes: a negative electrode; a positive electrode, where the positive electrode includes a current collector and a positive electrode active material layer provided on the current collector, the positive electrode active material layer includes a positive electrode active material, and the positive electrode has an active specific surface area of X m2/g; and an electrolyte, where the electrolyte contains an additive A, the additive A contains LiPO2F2, and a weight percentage of the LiPO2F2 is Y % based on a weight of the electrolyte, where 0.005≤X/Y≤2 is satisfied. The electrochemical device has higher cycling performance, storage performance, and overcharge performance, as well as lower impedance.