Amorphous Lithium Boron Oxide Coating for Cathode Stability
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Solution Overview
Problem
Lithium secondary batteries face structural instability and reduced lifespan due to repeated charging and discharging, especially at high temperatures, and existing coating solutions often result in non-uniform crystallized coatings that fail to perform optimally over time.
Innovation Solution
A cathode active material with a coating layer composed of an amorphous phase containing lithium oxide and boron oxide, which is uniformly applied at a low cost, improving cycle and capacity characteristics, particularly at high temperatures, by using boron oxide's optimized heat treatment temperature and excluding tungsten oxide to prevent crystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the cathode active material surface, then structural stability and lifespan are improved, but the coating layer crystallizes during heat treatment causing non-uniform coating and reduced performance
Solution Approach 1:
The patent changes the chemical composition parameters of the coating layer by incorporating lithium oxide (Li2O) and boron oxide (B2O3) in specific ratios. This compositional modification lowers the heat treatment temperature required for coating formation from conventional high temperatures (400-450°C for tungsten-based coatings) to 250-350°C, thereby preventing crystallization and achieving uniform amorphous coating while maintaining structural stability
Solution Approach 2:
The patent creates a composite coating layer combining lithium oxide and boron oxide to achieve synergistic effects. Li2O provides lithium ion conductivity and coating adhesion, while B2O3 forms the amorphous glassy matrix that prevents crystallization. This composite approach enables uniform coating formation at low temperatures while improving both structural stability and coating uniformity
2Reliability
If tungsten oxide is used as coating material to improve low-temperature characteristics, then low-temperature performance is enhanced, but heat treatment temperature increases to 400-450°C causing crystallization and increased process cost
Solution Approach 1:
The patent changes the coating material composition from tungsten oxide to a lithium oxide-boron oxide system. This substitution dramatically lowers the heat treatment temperature from 400-450°C to 250-350°C, preventing crystallization while maintaining coating effectiveness. The lower processing temperature also reduces energy consumption and process costs
Solution Approach 2:
The patent replaces expensive tungsten oxide with more economical lithium oxide and boron oxide materials. This substitution reduces both material costs and process costs associated with high-temperature heat treatment, achieving cost-effective coating formation at lower temperatures
3Ease of manufacture
If conventional coating materials are used, then coating formation is achieved, but residual lithium remains on the core surface causing capacity loss and reduced cycle characteristics
Solution Approach 1:
The patent employs lithium oxide in the coating layer that reacts with residual lithium on the core surface during low-temperature heat treatment. The Li2O acts as a lithium scavenger, chemically binding residual lithium to form stable lithium compounds, thereby eliminating capacity loss sources while the coating simultaneously provides protective functions
Solution Approach 2:
The patent converts the harmful effect of residual lithium (which causes capacity loss) into a beneficial process by using Li2O in the coating to chemically react with and remove the residual lithium. The previously harmful residual lithium becomes part of the stable coating structure, improving cycle characteristics while the coating formation process simultaneously addresses both coating protection and lithium removal
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 amorphous phase coating layer enhances the cycle and capacity characteristics of lithium secondary batteries, including high-temperature performance, by ensuring uniform coverage and reducing residual lithium, thereby improving the battery's overall efficiency and lifespan.
Implementation Method 1
the coating layer includes an amorphous phase containing lithium oxide and boron oxide in a form of mixture
Implementation Method 2
for boron (B), about 250 to about 350° C. is an optimized heat treatment temperature to form a coating layer
Data Source
AI summary
Disclosed is a cathode active material for a lithium secondary battery including a core containing lithium composite metal oxide, and a coating layer disposed on the core and including an amorphous phase, wherein the amorphous phase contains lithium oxide and boron oxide in a form of mixture.