Large Monocrystal-Like Cathode Particles Without Crushing Damage
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Solution Overview
Problem
Commercial ternary materials for lithium-ion batteries, which are typically spherical or spherical-like secondary particles, require crushing, leading to damage of coating layers and poor stability, resulting in short cycle life due to intensified reactions with the electrolyte.
Innovation Solution
A method for preparing ternary positive materials with large monocrystal-like particles involves mixing nickel, cobalt, and manganese salts with a lithium salt, adjusting pH, and sintering in multiple stages to achieve stable particles that do not require crushing, maintaining structural integrity and improving cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercial ternary materials are used as spherical secondary particles, then the manufacturing process requires crushing, but this causes damage to coating layers and reduces stability
Solution Approach 1:
Instead of producing spherical secondary particles and then crushing them, the patent inverts the approach by directly synthesizing large monocrystal-like particles that maintain their structural integrity throughout processing, eliminating the need for crushing operations
Solution Approach 2:
The patent changes the particle morphology parameter from spherical secondary particles to large monocrystal-like particles, which fundamentally alters the material's mechanical properties and eliminates the need for crushing while improving stability
2Productivity
If ternary material is crushed during processing, then particle size is reduced, but this intensifies reaction with electrolyte and shortens cycle life
Solution Approach 1:
Rather than crushing particles to achieve desired size distribution, the patent inverts the approach by directly growing particles to the appropriate size range as large monocrystals, eliminating the crushing step that damages the material and extends cycle life
3Ease of manufacture
If coating layers are damaged during crushing, then material processing is completed, but this reduces morphological and structural stability
Solution Approach 1:
The patent inverts the conventional approach by eliminating the crushing step entirely and directly synthesizing particles with the desired characteristics, thereby preserving coating layers and maintaining morphological and structural stability throughout manufacturing
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 produces ternary positive materials with improved morphological and structural stability, enhancing cycle performance and reducing production costs by eliminating the need for crushing, while maintaining high specific capacities and long cycle life.
Implementation Method 1
the mixed powder is heated to a sintering temperature to form a sintered cake
Implementation Method 2
the mixed powder is heated to a sintering temperature
Data Source
AI summary
A method for preparing ternary positive material in a lithium battery includes mixing nickel salt, cobalt salt, and manganese salt to form a mixed solution. A precipitant and a complexing agent are added into the mixed solution, thereby adjusting a pH value to a range of 10.5 to 12 and obtaining a precursor A. The precursor A and lithium salt are ground by a ball mill to obtain a precursor B, precursor B then being sintered in an air or oxygen atmosphere. The sintering includes heating at a first heating speed of 5 to 15° C./min to a first temperature of 400 to 800° C. and being held at such temperature for 1 to 6 h, and heating at a second heating speed of 1 to 10° C./min to a second temperature of 900 to 980° C. and being held there for 8 to 10 h.