Zirconium Boride Additive for High-Voltage Battery Stability
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Solution Overview
Problem
Non-aqueous secondary batteries experience deterioration in cycle characteristics when charged at high voltages due to decomposition of fluoric compounds in the electrolyte, leading to reactions with the positive electrode material.
Innovation Solution
Incorporating heat-treated zirconium boride particles with an oxygen content of 1.1-1.4 mass % into a positive electrode active material comprising lithium transition metal complex oxide particles, which captures fluoride ions generated during charging and discharging, thereby suppressing deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage charging is applied to non-aqueous secondary batteries, then the operation voltage and power output are improved, but the cycle characteristic deteriorates due to decomposition of fluoric compounds in the electrolyte
Solution Approach 1:
Zirconium boride particles are introduced as an intermediary substance between the electrolyte and the positive electrode active material. These particles preferentially react with fluoride ions generated during high-voltage charging, forming a protective interface layer that prevents direct contact between the reactive fluoride ions and the positive electrode material, thereby maintaining cycle stability at high operating voltages
Solution Approach 2:
The harmful fluoride ions generated during high-voltage charging are converted into a beneficial protective layer through their reaction with zirconium boride particles. The fluoride ions that would otherwise attack and degrade the positive electrode material are instead consumed by the zirconium boride, forming a stable interface that protects the electrode structure and maintains long-term cycling performance
2Reliability
If zirconium boride particles are added to the positive electrode material, then the cycle characteristic is improved, but the electrical conductivity may be affected
Solution Approach 1:
The oxygen content of zirconium boride particles is precisely controlled within the range of 0.5-5 mass% through heat treatment in oxygen-containing atmospheres at specific temperatures and durations. This parameter optimization ensures that the zirconium boride particles provide sufficient fluoride ion trapping capability while maintaining adequate electrical conductivity for battery operation
Solution Approach 2:
Zirconium boride particles are distributed locally throughout the positive electrode material at controlled concentrations (0.1-5 mass%). This local distribution strategy ensures that fluoride ion protection is provided at critical interfaces where fluoride generation occurs, while minimizing the overall impact on the bulk electrical conductivity of the electrode material
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 use of heat-treated zirconium boride particles maintains excellent cycle characteristics even at high charging voltages, enhancing the stability and performance of non-aqueous secondary batteries.
Implementation Method 1
zirconium boride particles...captures fluoride ions generated during charging and discharging
Implementation Method 2
performing a heat treatment on zirconium boride particles in an oxygen-containing atmosphere at a heat treatment temperature of not less than 220° C. and not more than 390° C.
Data Source
AI summary
A method for producing a positive electrode material for non-aqueous secondary batteries includes: performing a heat treatment on zirconium boride particles in an oxygen-containing atmosphere at a heat treatment temperature of not less than 220° C. and not more than 390° C., thereby obtaining heat-treated particles; and mixing the heat-treated particles with a positive electrode active material which contains a lithium transition metal complex oxide particles including at least one of cobalt and nickel in a composition thereof and having a layered structure, such that a content of the heat-treated particles relative to the lithium transition metal complex oxide particles is, as zirconium, not less than 0.25 mol % and not more than 2.2 mol %, thereby obtaining a positive electrode material for non-aqueous secondary batteries.