Sacrificial Cathode Material Calcination for Low 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 deterioration of 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, reducing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
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 changes the calcination parameters (oxygen partial pressure from atmospheric to controlled low levels, humidity control, temperature profiles) to transform the reaction environment. This enables complete consumption of lithium oxide without excess, producing Li6CoO4 with minimal residual by-products, thus maintaining high irreversible capacity while eliminating oxygen gas generation
Solution Approach 2:
The patent employs a controlled inert atmosphere during calcination, specifically using nitrogen or argon gas with controlled oxygen partial pressure (0.1-10% O2). This inert environment prevents unwanted oxidation reactions and controls the formation of Li6CoO4, ensuring complete reaction of lithium oxide without generating residual by-products that would cause oxygen evolution during battery operation
2Quantity of substance
If residual lithium oxide by-products remain in the prepared additive, then the irreversible capacity is maintained, but the by-products react with binder components increasing viscosity or causing gelation
Solution Approach 1:
By precisely controlling calcination parameters (temperature, oxygen partial pressure, humidity, time), the patent achieves complete reaction of lithium oxide to form Li6CoO4 without residual by-products. This parameter optimization ensures the additive does not react with binder components during slurry preparation, maintaining proper viscosity and preventing gelation while preserving the required irreversible capacity
3Quantity of substance
If oxygen gas is generated during charging/discharging, then the irreversible capacity function is performed, but volume expansion occurs leading to deterioration of battery performance
Solution Approach 1:
The patent optimizes calcination parameters (oxygen partial pressure, humidity, temperature, time) to produce Li6CoO4 with minimal residual lithium oxide. This prevents oxidation reactions during charging/discharging that would generate oxygen gas, thereby eliminating volume expansion and maintaining battery performance stability while preserving the necessary irreversible capacity for high-capacity electrode applications
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 significantly reduces oxygen gas generation, enhancing battery stability and life by maintaining or increasing charge/discharge capacity.
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
the calcining temperature may be 500 to 800° C.
Implementation Method 3
satisfies at least one of Equations 1 and 2 below, as measured by X-ray diffraction
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.