Positive Electrode Material Purification With Low-Dew-Point Calcination
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Solution Overview
Problem
The challenge is to develop a manufacturing method for a highly purified positive electrode active material that maintains its crystal structure integrity during repeated charging and discharging cycles, while also enhancing the lithium-ion secondary battery's capacity and reliability, particularly in lithium-ion secondary batteries used in portable devices and electric vehicles.
Innovation Solution
A method involving the formation of a hydroxide containing transition metals using a basic aqueous solution, followed by mixing with a lithium compound and heating in an oxygen-containing atmosphere with a dew point of -50°C or lower to produce a composite oxide with high purity, ensuring the battery's stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used for positive electrode active material, then production cost is reduced, but material purity is insufficient and crystal structure integrity deteriorates during charging and discharging cycles
Solution Approach 1:
The patent applies parameter changes by controlling the dew point of the oxygen-containing atmosphere to -50°C or lower during heating treatment. This specific parameter change in the manufacturing environment enables the formation of a composite oxide with enhanced crystal structure integrity and high purity, resolving the contradiction between manufacturing precision and ease of manufacture
Solution Approach 2:
The patent employs preliminary action by preparing a mixture of lithium compound and hydroxide before heating treatment. This preliminary mixing and preparation step ensures that the raw materials are properly combined and positioned, which facilitates subsequent crystal formation and maintains structural integrity during charging and discharging cycles
2Quantity of substance
If material purity is increased to enhance battery capacity, then charge and discharge capacity improves, but manufacturing process complexity increases
Solution Approach 1:
The patent changes the atmospheric parameter (dew point to -50°C or lower) during heating to achieve high material purity. This parameter change enables the production of high-purity composite oxide that enhances battery capacity without requiring excessively complex manufacturing processes
Solution Approach 2:
The patent replaces complex mechanical purification processes with a controlled chemical heating process in an oxygen-containing atmosphere. This substitution achieves high material purity through chemical reactions and phase transformations rather than through complex mechanical separation and purification steps
3Stability of the object's composition
If heating treatment is performed to form composite oxide, then crystal structure is formed, but energy consumption increases
Solution Approach 1:
The patent optimizes heating parameters by controlling the atmospheric dew point to -50°C or lower during heating treatment. This parameter optimization enables crystal structure formation at controlled temperatures, achieving the desired crystal integrity while managing energy consumption through efficient thermal processing
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 results in a positive electrode active material with high purity and excellent charge and discharge cycle performance, leading to improved battery capacity and reliability, ensuring safety and efficiency in lithium-ion secondary batteries.
Implementation Method 1
a first step of forming a hydroxide containing the transition metal using at least a basic aqueous solution and an aqueous solution containing the transition metal
Implementation Method 2
a fourth step of heating the mixture to form a composite oxide containing the lithium and the transition metal
Implementation Method 3
heating the mixture to form a composite oxide
Data Source
AI summary
A manufacturing method of a highly purified positive electrode active material is provided. Alternatively, a manufacturing method of a positive electrode active material whose crystal structure is not easily broken even when charging and discharging are repeated is provided. Provided is a manufacturing method of a positive electrode active material containing lithium and a transition metal. The manufacturing method includes a first step of forming a hydroxide containing the transition metal using a basic aqueous solution and an aqueous solution containing the transition metal, a second step of preparing a lithium compound, a third step of mixing the lithium compound and the hydroxide to form a mixture, and a fourth step of heating the mixture to form a composite oxide containing lithium and the transition metal. A material with a purity higher than or equal to 99.99% is prepared as the lithium compound in the second step, and the heating is performed in an oxygen-containing atmosphere with a dew point lower than or equal to −50° C. in the fourth step.