Li-Ion Cathode Electrolyte Additive for High-Temperature Stability
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Solution Overview
Problem
Lithium-ion batteries face performance deterioration at high temperatures due to ion dissolution and lithium dendrite formation, which affects their electrochemical performance and stability.
Innovation Solution
A lithium-ion battery design incorporating a positive electrode active material doped or coated with specific metal elements and a non-aqueous electrolyte containing a cyclic sulfate compound, which forms a stable interface film to prevent ion dissolution and enhance material stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If transition metal elements are used for doping or surface coating to improve electrochemical performance, then the cutoff voltage and applicable temperature range are improved, but the metal elements dissolve from the electrolyte at high temperature and migrate to the negative electrode, destroying the SEI film and producing lithium dendrites
Solution Approach 1:
The patent introduces an intermediary substance (specific additive compound with cyclic structure containing oxygen and nitrogen atoms) into the electrolyte that acts as a mediator between the transition metal elements and the negative electrode. This additive preferentially reacts with the transition metal ions to form stable complexes, preventing their migration to the negative electrode and subsequent destruction of the SEI film, thereby resolving the contradiction between extending temperature range and maintaining high-temperature reliability
Solution Approach 2:
The patent converts the harmful effect of transition metal ion dissolution and migration into a beneficial effect by designing the additive to selectively complex with these metal ions. The previously harmful migrating metal ions are now trapped in stable complexes within the electrolyte or at the positive electrode interface, preventing them from reaching the negative electrode while still allowing the doping/coating to provide its stabilizing effect on the positive electrode structure
2Quantity of substance
If doping and surface coating are applied to improve battery capacity, then the energy density is improved, but the movement stability of lithium-ions between electrolyte and electrode materials is affected, deteriorating electrochemical performance
Solution Approach 1:
The patent changes the chemical environment parameters of the electrolyte by introducing the specific additive compound. This additive modifies the interfacial chemistry between the electrolyte and electrode materials, creating a more favorable chemical environment for lithium-ion transport. The additive forms a protective interface layer that facilitates lithium-ion movement while preventing harmful side reactions, thus resolving the contradiction between increasing capacity and maintaining ion transport stability
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 solution improves the electrochemical performance of lithium-ion batteries at high temperatures by stabilizing the positive electrode material, maintaining battery impedance at a low level and enhancing cycle and storage capacity retention.
Implementation Method 1
the non-aqueous electrolyte includes a solvent, an electrolyte salt and a compound represented by Structural formula 1... which forms a stable interface film to prevent ion dissolution
Implementation Method 2
the compound represented by Structural formula 1... forms a stable interface film
Implementation Method 3
the positive electrode active material is doped with a compound containing metal element A... further stabilize the positive electrode active material, prevent the cell of the positive electrode active material from changing
Implementation Method 4
or coated with a compound containing metal element A... enhance the overall stability of the material
Implementation Method 5
the cyclic sulfate can complex the cation of doped or coated metal element A in a certain proportion under the catalysis of transition metal M
Implementation Method 6
improve the movement stability of lithium-ions between electrolyte and electrode materials
Data Source
AI summary
The existing positive electrode material that is doped or coated with compound has the problem OF ion dissolution and battery performance deterioration at high temperature. To solve it, the invention provides a lithium-ion battery, comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode material layer, the positive electrode material layer comprises a positive electrode active material, and the positive electrode active material comprises LiMO2, where M is selected from one or more of Ni, Co and Mn, and the positive electrode active material is doped with a compound containing metal element A and/or coated with a compound containing metal element A, the non-aqueous electrolyte comprises a solvent, an electrolyte salt and a compound represented by Structural formula 1. The lithium-ion battery provided by the invention could effectively improve the overall stability of the material.