Sacrificial Positive Electrode Material With Reduced Battery Gas Generation
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Solution Overview
Problem
Conventional positive electrode additives generate excessive oxygen gas during battery charging and discharging due to residual by-products like lithium oxide, leading to volume expansion and viscosity increase, which deteriorate battery performance.
Innovation Solution
A method of preparing a sacrificial positive electrode material by calcining a mixture of lithium oxide and cobalt oxide under an atmosphere with controlled humidity and oxygen partial pressure, producing lithium cobalt metal oxide with specific X-ray diffraction characteristics to minimize gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional irreversible additive (Li6CoO4) is prepared by reacting cobalt oxide with excess lithium oxide, then the irreversible capacity is increased, but residual lithium oxide by-products remain causing oxidation and oxygen gas generation during charging/discharging
Solution Approach 1:
The patent applies inert atmosphere by conducting the calcination reaction in a nitrogen atmosphere. This prevents residual lithium oxide from reacting with moisture and oxygen during storage and battery operation, thereby eliminating the source of oxygen gas generation while preserving the high irreversible capacity needed for battery performance enhancement.
Solution Approach 2:
The patent changes the reaction parameters by controlling the calcination temperature (500-800°C) and atmosphere composition (nitrogen with controlled oxygen content). These parameter changes ensure complete reaction of lithium oxide while preventing secondary oxidation reactions, thus achieving high irreversible capacity without harmful by-products.
2Use of energy by moving object
If residual lithium oxide by-products remain in the irreversible additive, then the irreversible capacity is maintained, but the binder component reacts with by-products increasing viscosity and causing gelation
Solution Approach 1:
By preparing the irreversible additive in a nitrogen atmosphere, the patent prevents residual lithium oxide from reacting with moisture in the binder components during slurry preparation. This eliminates gelation and viscosity increase, making electrode manufacturing straightforward while preserving the desired irreversible capacity.
3Use of energy by moving object
If residual lithium oxide by-products are present, then the irreversible capacity is sufficient, but volume expansion occurs due to oxygen gas generation leading to battery performance deterioration
Solution Approach 1:
The patent uses nitrogen atmosphere during calcination to prevent formation of residual lithium oxide that would otherwise generate oxygen gas during battery operation. This eliminates volume expansion and maintains battery performance stability over charge/discharge cycles while preserving the necessary irreversible capacity.
Solution Approach 2:
The patent converts the potentially harmful residual lithium oxide into a beneficial state by controlling the reaction conditions. The lithium oxide completely reacts to form the desired Li6CoO4 structure without harmful by-products, transforming what would be a source of gas generation into a stable, high-performance 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
Reduces oxygen gas generation, enhancing battery stability and life by maintaining or increasing charge/discharge capacity while minimizing impurities.
Implementation Method 1
calcining a raw material mixture of lithium oxide (Li2O) and cobalt oxide (CoO) under an atmosphere containing an inert gas and oxygen gas
Implementation Method 2
as measured by X-ray diffraction: A/B≤0.1, C/D≤0.35 wherein A represents the intensity of the strongest peak among the peaks appearing in the range of 2θ=18.9±0.1°
Data Source
AI summary
A disclosure sacrificial positive electrode material with reduced gas generation and a method of preparing the same are disclosed herein. In some embodiments, a method includes calcining a mixture of lithium oxide (Li2O) and cobalt oxide (CoO) in an atmosphere containing an inert gas and oxygen gas and having a relative humidity of 20% or less, wherein the oxygen gas is at a partial pressure of 1% or less, to prepare a lithium cobalt metal oxide represented by Chemical Formula (1):LixCo(1−y)MyO4−zAz [Chemical Formula 1]M is at least one selected from the group consisting of Ti, Al, Zn, Zr, Mn and Ni, A is a halogen, x, y and z are 5≤x≤7, 0≤y≤0.4, and 0≤z≤0.001. A battery having the sacrificial positive electrode material can have reduced gas generation in the electrode assembly at the time of charging the battery, and thus the stability and life of the battery are improved.