Lithium-Ion Electrolyte Additives for Sub-Zero Impedance Control
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Solution Overview
Problem
Lithium-ion batteries exhibit poor performance at sub-zero temperatures due to rapid impedance rise and slower ion transport, limiting their use in extreme environments.
Innovation Solution
Incorporating silicic acid, silicate, metasilicate, or their salts as additives in the electrolyte composition of lithium-ion batteries, which enhance low-temperature performance without compromising ambient temperature performance by modifying the solid electrolyte interphase and reducing charge transfer impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte systems are used in lithium-ion batteries, then stable performance at ambient temperature is achieved, but performance deteriorates significantly at sub-zero temperatures due to rapid impedance rise and slower ion transport
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating specific additives (lithium fluorosulfonate at 0.05-5 wt%, lithium difluoro(oxalato)borate at 0.05-5 wt%, and vinylene carbonate at 0.01-1 wt%) to change the chemical parameters of the electrolyte system. These compositional changes enable the electrolyte to maintain lower impedance and better ionic conductivity at sub-zero temperatures while preserving ambient temperature performance
Solution Approach 2:
The patent creates a composite electrolyte system by combining conventional lithium salt and carbonate solvent with specifically selected additive compounds. This composite approach leverages the beneficial effects of each component: the lithium salts provide ionic conductivity, the carbonates provide solvent stability, and the additives modify the solid electrolyte interphase to reduce low-temperature impedance
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 additives improve lithium-ion battery performance by maintaining or exceeding 1-7% capability retention at temperatures as low as -20°C, with optimal performance achieved at a moderate concentration of 0.2% silicic acid, enhancing energy density and capacity retention while maintaining ambient temperature performance.
Implementation Method 1
Incorporating silicic acid, silicate, metasilicate, or their salts as additives in the electrolyte composition of lithium-ion batteries, which enhance low-temperature performance without compromising ambient temperature performance by modifying the solid electrolyte interphase and reducing charge transfer impedance
Data Source
AI summary
The present invention provides for lithium battery comprising (a) a cathode or an anode, or both, comprising an additive, or (b) an electrolyte composition comprising optionally an ether solvent, optionally an amphiphilic molecule, an additive, an electrolyte solvent, and a lithium salt; wherein the additive is a silicic acid, silicate, metasilicate, or salt thereof, or a mixture thereof. The present invention also provides for particles in lithium ion-battery electrolytes to improve low temperature performance.