Positive Electrode Active Material Combustion Synthesis for Single Particles
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Solution Overview
Problem
The existing methods for preparing lithium metal oxide positive electrode active materials for lithium secondary batteries are complex, time-consuming, and generate environmental pollution, with issues such as particle breakage, increased surface area leading to gas generation and degradation, and high initial resistance due to low lithium mobility and formation of electrochemically inactive rock salt phases.
Innovation Solution
A method involving the preparation of a mixed solution with specific fuels like urea and citric acid, and metal raw materials, followed by heating and heat treatment at lower temperatures to form single particles, reducing processing time and preventing rock salt phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional precipitation method using alkali and metal salt is used to prepare layered lithium metal oxide, then the positive electrode active material can be obtained, but the preparation process becomes complicated and time-consuming, and a large amount of wastewater causing environmental pollution is generated
Solution Approach 1:
The invention changes the chemical parameters of the preparation process by replacing conventional alkali precipitation with a combustion synthesis method using fuel-oxidizer reactions. This fundamentally alters the reaction mechanism from gradual precipitation to rapid combustion, simplifying the process while maintaining product quality
Solution Approach 2:
The invention extracts and removes the problematic alkali precipitation step from the conventional process, replacing it with a direct combustion synthesis approach that eliminates wastewater generation while maintaining the ability to produce high-quality lithium metal oxide
2Reliability
If the sintering temperature is increased to prepare single particle lithium metal oxide, then particle breakage is reduced, but the initial resistance increases due to low lithium mobility and formation of electrochemically inactive rock salt phase
Solution Approach 1:
The invention changes the temperature parameter from high sintering temperature to low-temperature combustion synthesis. This parameter change allows single particle formation without the adverse effects of high temperature, maintaining both structural integrity and electrochemical performance
Solution Approach 2:
The invention replaces the thermal-mechanical sintering process with a chemical combustion process. Instead of relying on mechanical pressure and high temperature to form particles, the combustion reaction directly synthesizes single particles with controlled morphology and composition
3Volume of moving object
If many primary particles are aggregated to form secondary particle lithium metal oxide, then the particle size is increased, but particle breakage occurs easily during rolling process and cracks occur during charge and discharge
Solution Approach 1:
The invention segments the particle formation process to create single primary particles rather than aggregated secondary particles. The combustion synthesis method produces discrete, uniformly sized particles that maintain their integrity without requiring aggregation, thus improving mechanical strength while controlling particle size
4Reliability
If alkali and metal salt are used in the precipitation method, then the layered lithium metal oxide can be formed, but a large amount of wastewater is generated causing environmental pollution
Solution Approach 1:
The invention converts the harmful wastewater byproduct into a beneficial outcome by using combustion synthesis that produces water vapor and carbon dioxide instead of liquid wastewater. The fuel combustion process transforms potential pollution into gaseous products that can be easily managed
Solution Approach 2:
The invention extracts and eliminates the wastewater generation step from the conventional process by replacing alkali precipitation with combustion synthesis, thereby removing the source of environmental pollution while maintaining product quality
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
This method reduces processing time, improves resistance and capacity characteristics, prevents cation mixing, and decreases gas generation by reducing lithium by-products, allowing for larger particle size and uniform particle formation at lower temperatures.
Implementation Method 1
heating the mixed solution to combust the mixed solution into a form of powder
Implementation Method 2
performing a heat treatment on the powder obtained in step (2)
Data Source
AI summary
A positive electrode active material for a lithium secondary battery and a method for preparing the same is disclosed herein. In some embodiments, a method comprises heating a mixed solution to combust the mixed solution into a powder, wherein the mixed solution includes a first fuel, a second fuel, a metal raw material, and water, and heat treating the powder wherein the first fuel is least one first fuel selected from the group consisting of urea, glycine, carbohydrazide, oxalyldihydrazide, and hexamethylenetetramine, the second fuel is at least one second fuel selected from the group consisting of citric acid, oxalic acid, sucrose, glucose, and acetylacetone, and the metal raw material includes a lithium raw material, a nickel raw material, a cobalt raw material, and a manganese raw material.