Lithium-Ion Battery Electrolyte for Stable High-Nickel Cathodes
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Solution Overview
Problem
The high cost and insufficient energy density of lithium-ion batteries for electric vehicles are hindered by lattice and surface instability of high-nickel layered oxide positive electrode active materials, which shorten battery life and are not adequately addressed by current dopants, especially in high-temperature environments.
Innovation Solution
A lithium-ion battery electrolyte containing a specific additive with an unsaturated bond and nitrogen atom forms a dense CEI film, capturing transition metal ions and inhibiting their diffusion, thereby improving safety and performance under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel layered oxide positive electrode active materials are used to improve energy density, then the energy density is improved, but lattice and surface instability occurs which shortens battery life
Solution Approach 1:
The patent introduces a specific additive (compound with nitrogen atom and unsaturated bond) as an intermediary substance that mediates between the high-nickel cathode material and the electrolyte. This additive forms a protective interface layer that stabilizes the cathode surface, preventing lattice instability and transition metal dissolution, thereby extending battery life while maintaining high energy density
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by adding a specific compound (0.05-3 wt%) with nitrogen atoms and unsaturated bonds. This parameter change transforms the electrolyte's ability to form stable interface films, enabling the system to tolerate high-nickel cathode materials without suffering from lattice instability
2Stability of the object's composition
If conventional dopants are added to high-nickel layered oxide to improve stability, then some stability is improved, but high-temperature performance is not adequately enhanced
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte system by introducing compounds with specific functional groups (nitrogen atoms and unsaturated bonds). This parameter change enables the formation of temperature-resistant interface films that maintain stability at high temperatures, unlike conventional dopants that only address lattice stability at room temperature
Solution Approach 2:
The patent creates a composite interface structure consisting of the electrolyte additive compound and the cathode material surface. This composite interface layer combines the stabilizing effect on lattice structure with additional high-temperature resistance properties, achieving both lattice stability and improved high-temperature performance
3Device complexity
If transition metal ions are not captured at the interface, then the battery structure remains simple, but transition metal ions diffuse to the negative electrode causing internal short circuit
Solution Approach 1:
The patent introduces the electrolyte additive as an intermediary trapping agent at the cathode-electrolyte interface. This intermediary substance has specific chemical properties (nitrogen atoms and unsaturated bonds) that enable it to capture and immobilize transition metal ions, preventing their migration to the negative electrode and avoiding internal short circuits
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 electrolyte effectively prevents internal short circuits and enhances battery safety and performance by neutralizing acidity and capturing transition metal ions, improving high-temperature stability and capacity recovery.
Implementation Method 1
the dissolved transition metal ions are captured on the interface, preventing the transition metal ions from diffusing to the negative electrode
Implementation Method 2
the additive forms a dense CEI film at the interface
Implementation Method 3
the invention provides a lithium-ion battery electrolyte and an application thereof that may produce acid-base neutralization effect with protons H +
Data Source
AI summary
The invention provides a lithium-ion battery electrolyte and an application thereof, wherein the lithium-ion battery electrolyte includes at least: a non-aqueous solvent; a lithium salt; an additive; and hydrogen fluoride, wherein the additive includes a substance represented by a following general formula (I): wherein R1, R2, and R3 are respectively substituents with 1 to 6 carbon atoms, 0 to 4 unsaturation, and 0 to 3 heteroatoms; the heteroatoms are selected from at least one of nitrogen or oxygen; and n is 0 to 2; a content of the additive in the lithium-ion battery electrolyte is 0.05 wt% to 3 wt%; and a content of the hydrogen fluoride in the lithium-ion battery electrolyte is 30 ppm to 200 ppm.