Vanadium Oxide Coating for Nickel-Rich Lithium Battery Cathodes
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Solution Overview
Problem
Nickel-rich-based positive active materials in lithium rechargeable batteries face challenges with structure stability at high temperatures and the presence of lithium impurities, which lead to gelation, gas generation, and reduced capacity due to side reactions with CO2 and H2O, and conventional surface treatments worsen conductivity and ion mobility.
Innovation Solution
A nickel-containing lithium transition metal composite oxide with a coating layer of vanadium oxide or lithium vanadium oxide is applied to the surface, which removes lithium impurities and suppresses side reactions, enhancing stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surface treatment materials (metal oxides, metal phosphates, metal fluorides, carbon compounds) are applied to the nickel-rich-based positive active material, then structure stability is improved and side reactions are suppressed, but battery conductivity and lithium ion conductivity deteriorate, causing increased initial resistance and decreased initial capacity
Solution Approach 1:
The patent applies a composite coating layer comprising both inorganic material (metal oxide, metal phosphate, metal fluoride, or carbon compound) and organic material (polymer or small molecule) on the nickel-rich-based positive active material. This composite structure combines the structure stabilization effect of inorganic materials with the conductivity enhancement of organic materials, resolving the contradiction between reliability and energy loss.
2Stability of the object's composition
If conventional surface treatment materials are applied to remove lithium impurities, then structure stability is improved, but the treatment materials act as insulators and cause increased initial resistance
Solution Approach 1:
The patent uses a composite coating of inorganic and organic materials where the inorganic component provides surface stability and the organic component maintains low resistance. This composite approach allows simultaneous achievement of surface stability and low initial resistance, resolving the contradiction between these two parameters.
3Quantity of substance
If lithium impurities remain on the surface of the nickel-rich-based positive active material, then high capacity is achieved, but gelation occurs during electrode slurry manufacture and uniformity of electrode plate deteriorates
Solution Approach 1:
The patent applies a surface treatment layer that acts as an intermediary between the nickel-rich-based positive active material and the electrode slurry components. This treatment layer prevents gelation while maintaining capacity, and ensures uniform distribution in the electrode slurry, thereby improving manufacturing precision without sacrificing capacity.
4Quantity of substance
If lithium impurities remain on the surface, then high capacity is maintained, but Li2CO3 decomposition during electrochemical reaction generates gas and forms initial irreversible capacity
Solution Approach 1:
The surface treatment layer serves as a protective intermediary that prevents direct contact between lithium impurities and the electrolyte, thereby suppressing Li2CO3 decomposition and gas generation during electrochemical reactions. This allows the battery to maintain high capacity while eliminating harmful gas generation.
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 battery's safety, high-rate characteristics, and cycle-life performance by preventing gelation and gas generation, while maintaining high capacity and low cost.
Implementation Method 1
surface-treating a nickel-rich-based positive active material with a compound capable of reacting with a lithium compound remaining on the surface thereof to remove the lithium compound
Implementation Method 2
controlling a side reaction between an electrode and an electrolyte solution due to a stable coating layer on the surface of the compound
Data Source
AI summary
Disclosed are a positive active material for a rechargeable lithium battery including a nickel-containing lithium transition metal composite oxide and a coating layer positioned on the surface of the lithium transition metal composite oxide, wherein the coating layer includes vanadium oxide, lithium vanadium oxide, or a combination thereof, a method of manufacturing the same, and a rechargeable lithium battery including the same.