Carbon-Coated Lithium Complex Oxide for High-Voltage Battery Stability
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Solution Overview
Problem
High-voltage lithium batteries face challenges with electrolyte oxidation and low conductivity due to high lithium content in positive electrode active materials, especially in high-temperature environments, which affects their performance and stability.
Innovation Solution
A positive electrode active material is developed with a lithium complex oxide coated with a carbon layer, where the carbon coating is formed through a gaseous reaction, enhancing conductivity and durability while preventing electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-voltage positive electrode active material is used to increase energy density, then energy storage capacity is improved, but electrolyte oxidation occurs and conductivity decreases
Solution Approach 1:
A carbon coating layer is applied as an intermediary between the lithium complex oxide and the electrolyte. This carbon layer prevents direct contact and chemical reactions between the high-voltage positive electrode material and the electrolyte, thereby suppressing oxidation and improving reliability while maintaining high energy storage capacity
Solution Approach 2:
The patent creates a composite structure combining lithium complex oxide (for high voltage and energy density) with a carbon coating layer (for stability and conductivity). This composite material approach allows the system to simultaneously achieve high energy storage capacity and electrolyte stability by combining materials with complementary properties
2Use of energy by moving object
If high-voltage positive electrode active material is used to increase energy density, then energy storage capacity is improved, but conductivity decreases
Solution Approach 1:
The carbon-coated lithium complex oxide composite combines the high energy density properties of lithium complex oxide with the high conductivity properties of carbon, achieving both improved energy storage capacity and maintained electrical conductivity
Solution Approach 2:
The carbon coating is applied locally on the surface of the lithium complex oxide particles, providing conductivity enhancement where it is most needed at the particle surfaces and interfaces, while preserving the bulk material's energy storage properties
3Use of energy by moving object
If lithium complex oxide with high lithium content is used, then energy storage capacity is improved, but conductivity deteriorates
Solution Approach 1:
The carbon coating creates a conductive network on the surface of the high-lithium-content complex oxide particles, compensating for the inherent low conductivity of the bulk material and enabling efficient electron transport while maintaining high energy storage capacity
4Power
If battery operates in high-temperature environment, then power output is improved, but temperature increases rapidly and stability decreases
Solution Approach 1:
The carbon coating layer serves as a thermal and chemical barrier between the positive electrode active material and the electrolyte, reducing parasitic reactions and heat generation during high-temperature operation, thereby improving stability while maintaining power output
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 carbon-coated lithium complex oxide improves the battery's conductivity, durability, and rate capability, extending its lifespan and performance, especially in high-temperature conditions.
Implementation Method 1
A positive electrode active material is developed with a lithium complex oxide coated with a carbon layer, where the carbon coating is formed through a gaseous reaction
Data Source
AI summary
A positive electrode active material including: a lithium complex oxide represented by Formula 1; and a carbon coating layer disposed on the lithium complex oxide, wherein, in a C1s XPS spectrum of the positive electrode active material, a peak intensity of a first peak at a binding energy from about 288 eV to about 293 eV is greater than a peak intensity of a second peak at a binding energy from about 283 eV to about 287 eV, and in an O1s X-ray photoelectron spectrum of the positive electrode active material, a peak intensity of a third peak at a binding energy from about 530.5 eV to about 535 eV is greater than a peak intensity of a fourth peak at a binding energy from about 527.5 electron volts to about 530 electron volts,LiaMbM′cM″dOe. Formula 1