Fluorine-Doped Cathode Lithium Additive for Stable High-Voltage Cycling
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Solution Overview
Problem
Existing cathode lithium-supplementing additives for lithium-ion batteries suffer from poor storage and processability, potential safety risks due to easy gas production, and unsatisfactory electrochemical performance such as low initial Coulombic efficiency.
Innovation Solution
A cathode lithium-supplementing additive doped with fluorine, where fluorine atoms replace oxygen atoms in the lithium-supplementing material, reducing residual alkali content and incorporating a hydrophobic fluoride and/or hydrophobic encapsulation layer to enhance stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-rich compounds are used as lithium-supplementing additives, then the lithium-supplementing effect is improved, but the material sensitivity to water increases and processing becomes difficult
Solution Approach 1:
The patent introduces a surface coating layer as an intermediary between the lithium-rich compound and the external environment. This coating layer acts as a protective barrier that prevents water and oxygen from directly contacting the reactive lithium-rich material, thereby maintaining both the lithium-supplementing effect and processing ease. The coating serves as a mediator that allows the material to function effectively without suffering from its inherent sensitivity to moisture.
Solution Approach 2:
The surface coating layer is designed as a thin, simple protective layer that can be applied during the manufacturing process. Rather than attempting to create perfectly stable lithium-rich compounds, the patent accepts the inherent reactivity and manages it through a straightforward coating approach that is easy to implement in production, treating the coating as a necessary protective element rather than a complex stabilization mechanism.
2Stability of the object's composition
If strict water control is implemented during processing, then material stability is improved, but production complexity and cost increase
Solution Approach 1:
The patent applies a protective surface coating to the lithium-rich compound during the manufacturing process as a preliminary protective measure. This coating is applied before the material is assembled into the battery, preemptively preventing water and oxygen exposure rather than requiring strict environmental controls during subsequent handling and assembly. This preliminary protection simplifies downstream processing and reduces production complexity.
Solution Approach 2:
The surface coating is implemented as a simple, cost-effective protective layer that can be applied using standard coating equipment. Rather than investing in complex water-controlled environments or specialized handling equipment, the patent uses an affordable coating approach that provides sufficient protection without significantly increasing production complexity or cost.
3Use of energy by moving object
If high voltage conditions are used, then battery energy density is improved, but gas production and safety risks increase
Solution Approach 1:
The patent converts the potential harm of high reactivity at high voltages into a benefit by using the surface coating to stabilize the material. The coating prevents direct contact between the lithium-rich compound and electrolyte components that would otherwise lead to gas-producing reactions. By managing the reactivity through the coating, the material can safely operate at high voltages to provide high energy density without the harmful gas production effects.
4Loss of substance
If existing lithium-supplementing materials are used, then lithium ion loss during initial charge is reduced, but initial Coulombic efficiency remains unsatisfactory
Solution Approach 1:
The patent modifies the chemical composition parameters of the lithium-supplementing material by incorporating specific elements or compounds that alter the electrochemical behavior. These compositional changes enable the material to provide lithium ions during initial charge while maintaining better Coulombic efficiency. The parameter changes in material composition allow simultaneous improvement of both lithium ion retention and efficiency metrics.
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 fluorine-doped cathode lithium-supplementing additive exhibits improved rate performance, high voltage stability, thermal stability, and safety performance, leading to enhanced lithium-supplementing effect, electrochemical performance, and storage stability, thereby improving battery cycle and safety performance.
Implementation Method 1
fluorine atoms replace oxygen atoms in the lithium-supplementing material
Implementation Method 2
incorporating a hydrophobic fluoride and/or hydrophobic encapsulation layer to enhance stability
Data Source
AI summary
A cathode lithium-supplementing additive, a preparation method thereof, and an application thereof are disclosed. The cathode lithium-supplementing additive of the present application includes a lithium-supplementing material, the lithium-supplementing material includes fluorine atoms, and the fluorine atoms replace oxygen atoms in the lithium-supplementing material and are in oxygen vacancies. According to the present application, the cathode lithium-supplementing additive is doped with fluorine, has relatively good high-voltage stability and thermal stability and relatively high rate performance, reduces the content of residual alkali, has high storage stability and good processability, and can also reduce gas production, thereby improving the cycle performance, electrochemical performance, and safety performance of a corresponding battery. In addition, the preparation method of the cathode lithium-supplementing additive can ensure stable structure and electrochemical performance of the cathode lithium-supplementing additive, have high efficiency, and reduce the production cost.