Dense Spherical Precipitation for Li-Ion Cathode Materials
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing cathode materials for lithium-ion cells face challenges in achieving high energy density and thermal safety, particularly due to the instability of manganese-based materials and the formation of irregularly shaped particles with high surface areas, which can lead to reactivity issues with organic electrolytes.
Innovation Solution
The development of a process for co-precipitating dense, spherical metal carbonates or phosphates, which are more stable and easier to handle than hydroxides, allowing for the production of active materials with improved morphology and thermal safety characteristics, such as lithium metal oxides and phosphates, by controlling pH and using chelating agents in aqueous solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If co-precipitation of mixed metal hydroxides is used to prepare cathode materials, then high material density can be achieved, but the process requires careful control of pH and atmosphere and produces irregularly shaped particles with high surface area
Solution Approach 1:
The patent changes the chemical parameter from hydroxide precipitation to carbonate precipitation, operating at lower pH (4-8) compared to hydroxide precipitation (pH>12). This parameter change simplifies process control while maintaining high material density and produces dense spherical particles with lower surface area.
Solution Approach 2:
The patent introduces carbonate ions as an intermediary precipitating agent that mediates the formation of spherical particles. The carbonate ions facilitate controlled precipitation that yields dense spherical morphology without requiring strict pH and atmosphere control needed for hydroxide precipitation.
2Quantity of substance
If co-precipitation of mixed metal hydroxides is used, then cathode materials can be produced, but the particles have high surface area leading to increased reactivity with organic electrolytes and reduced thermal safety
Solution Approach 1:
The patent employs carbonate precipitation to produce dense spherical particles. The spherical morphology reduces surface area compared to irregularly shaped hydroxide particles, thereby decreasing reactivity with organic electrolytes and improving thermal safety while maintaining production efficiency.
3Quantity of substance
If manganese-based materials are used to increase energy density, then high capacity can be achieved, but the materials exhibit instability and form irregular particles
Solution Approach 1:
The patent changes the precipitation conditions by using carbonate at lower pH (4-8) instead of hydroxide at high pH (>12). This parameter change stabilizes manganese-based materials during precipitation, preventing instability and irregular particle formation while maintaining high practical capacity.
4Quantity of substance
If hydroxide precipitation is used, then cathode materials can be produced, but the process occurs at high pH requiring expensive equipment and careful atmosphere control
Solution Approach 1:
The patent changes the operating pH from >12 (hydroxide precipitation) to 4-8 (carbonate precipitation). This parameter change eliminates the need for expensive corrosion-resistant equipment and strict atmosphere control, simplifying the manufacturing process while maintaining production capability.
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 approach results in active materials with enhanced energy density and thermal safety, as well as easier handling and lower production costs, by forming dense, spherical particles that maintain their shape during calcination and improve the performance of lithium-ion batteries.
Implementation Method 1
co-precipitation of mixed metal carbonates or phosphates provides dense spherical particles
Implementation Method 2
carbonate precipitation occurs at lower pH (from about pH 4 to about pH 8) than hydroxide precipitation (pH>12)
Data Source
AI summary
Processes are provided for making dense, spherical mixed-metal carbonate or phosphate precursors that are particularly well suited for the production of active materials for electrochemical devices such as lithium ion secondary batteries. Exemplified methods include precipitating dense, spherical particles of metal carbonates or metal phosphates from a combined aqueous solution using a precipitating agent such as ammonium hydrogen carbonate, sodium hydrogen carbonate, or a mixture that includes sodium hydrogen carbonate. Other exemplified methods include precipitating dense, spherical particles of metal phosphates using a precipitating agent such as ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, or a mixture of any two or more thereof. Further provided are compositions of and methods of making dense, spherical metal oxides and metal phosphates using the dense, spherical metal precursors. Still further provided are electrodes and batteries using the same.