NCM Cathode Oxide Coating for Lower Resistance and Longer Cycle Life
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Solution Overview
Problem
Lithium nickel cobalt manganese-based positive electrode active materials in lithium secondary batteries experience side reactions with the electrolyte during charging, leading to increased resistance and lifetime deterioration due to the generation of by-products, rock salt phase, oxygen release, and gas generation.
Innovation Solution
A thin and uniform metal oxide layer is coated on the surface of the lithium nickel cobalt manganese-based positive electrode active material using chemical vapor deposition, suppressing side reactions by reacting a metal oxide precursor with a carrier gas, thereby reducing resistance and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel cobalt manganese-based positive electrode active material is used to achieve high capacity, then battery capacity is improved, but side reactions occur at the electrolyte interface during charging causing resistance increase and lifetime deterioration
Solution Approach 1:
An aluminum oxide coating layer is applied as an intermediary substance between the lithium nickel cobalt manganese-based positive electrode active material and the electrolyte. This coating layer acts as a protective barrier that prevents direct contact and side reactions between the active material and electrolyte, thereby reducing resistance components and improving battery lifetime while maintaining high capacity
Solution Approach 2:
The invention creates a composite structure by combining lithium nickel cobalt manganese-based positive electrode active material with an aluminum oxide coating layer. This composite material structure allows the core active material to provide high capacity while the coating layer provides protection against degradation, resolving the contradiction between capacity and lifetime
2Quantity of substance
If lithium nickel cobalt manganese-based positive electrode active material is used to achieve high capacity, then battery capacity is improved, but resistance components including by-products and rock salt phase accumulate during operation
Solution Approach 1:
The aluminum oxide coating layer serves as an intermediary barrier that prevents the formation and accumulation of resistance components such as by-products and rock salt phase by blocking the interface between the active material and electrolyte where these harmful substances would otherwise form
Solution Approach 2:
The invention converts the potential harm of interface reactions into a benefit by using the controlled deposition of aluminum oxide during manufacturing. This coating process transforms what would be a harmful uncontrolled reaction zone into a beneficial protective interface that prevents harmful substance accumulation
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 method effectively minimizes side reactions at the electrolyte interface, improving battery resistance and lifetime by forming a dense and uniform metal oxide layer on the lithium nickel cobalt manganese-based positive electrode active material.
Implementation Method 1
A thin and uniform metal oxide layer is coated on the surface of the lithium nickel cobalt manganese-based positive electrode active material using chemical vapor deposition
Data Source
AI summary
Disclosed is a positive electrode material for a lithium secondary battery capable of improving the problems of resistance and lifetime deterioration of the battery by forming a thin and uniform metal oxide on the surface of the lithium nickel cobalt manganese-based positive electrode active material, and a method for preparing the same and a lithium secondary battery comprising the same. The method of preparing the positive electrode material for the lithium secondary battery comprises a method of coating a metal oxide on the surface of a lithium nickel cobalt manganese-based positive electrode active material through a chemical vapor deposition. The method includes placing the lithium nickel cobalt manganese-based positive electrode active material in a deposition apparatus and supplying a metal oxide precursor and a carrier gas, and the lithium nickel cobalt manganese-based positive electrode active material is stirred during deposition.