Cathode Active Material Combining Solid and Hollow Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary batteries face challenges in balancing volume energy density and rate performance, particularly in lithium-rich manganese-based materials, which exhibit poor cycling performance and rate performance due to structural changes during charging and discharging.
Innovation Solution
A positive electrode active material comprising a lithium-rich manganese-based material with a combination of solid and hollow particles, matched with lithium-containing phosphate, to enhance lithium ion transmission and compaction density, thereby improving both rate performance and volume energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If lithium-rich manganese-based material is used as positive electrode active material, then volume energy density can be improved, but rate performance and cycle performance deteriorate due to poor lithium ion transmission and structural changes during charging and discharging
Solution Approach 1:
The positive electrode active material is segmented into two distinct particle types: solid particles and hollow particles. This segmentation allows each particle type to fulfill different functional roles - solid particles provide high compaction density for volume energy density, while hollow particles facilitate lithium ion transmission for rate performance. The segmented structure resolves the contradiction by distributing the functional requirements across different particle morphologies rather than requiring a single particle type to satisfy both conflicting demands.
Solution Approach 2:
The invention creates a composite particle system comprising both solid lithium-rich manganese-based particles and hollow lithium-rich manganese-based particles. This composite material approach combines the advantages of solid particles (high density, good volume energy density) with the advantages of hollow particles (high surface area to volume ratio, excellent lithium ion diffusion). The composite structure enables simultaneous achievement of high volume energy density and high rate performance, resolving the technical contradiction between these two parameters.
2Volume of stationary object
If solid particles are used in lithium-rich manganese-based material, then compaction density and volume energy density are improved, but contact area with electrolyte solution decreases, reducing rate performance
Solution Approach 1:
The particle system is segmented into solid particles and hollow particles, each with distinct surface area to volume ratio characteristics. Solid particles contribute to high compaction density while hollow particles provide extensive contact area with electrolyte solution. This segmentation allows the system to achieve both high compaction density and high contact area simultaneously, resolving the contradiction between these two parameters.
Solution Approach 2:
Different particle morphologies are assigned to different functional requirements within the same material system. Solid particles with high density are used where compaction is needed, while hollow particles with high surface area to volume ratio are used where electrolyte contact is critical. This local quality differentiation allows each particle type to optimize for its specific function, resolving the contradiction between compaction density and contact area.
3Speed
If hollow particles are used to increase contact area with electrolyte solution, then rate performance is improved, but compaction density and volume energy density decrease
Solution Approach 1:
The particle system is segmented into hollow particles for high rate performance and solid particles for high compaction density. This segmentation allows the system to achieve both high lithium ion transmission speed and high compaction density by combining the advantages of both particle types rather than requiring a compromise in either direction.
Solution Approach 2:
The invention creates a composite particle system where hollow particles (providing high surface area to volume ratio and fast lithium ion diffusion) are combined with solid particles (providing high density). This composite material approach enables simultaneous achievement of high rate performance and high compaction density, resolving the technical contradiction between these two parameters.
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 combination of solid and hollow particles in the positive electrode active material increases the contact area with the electrolyte solution, facilitating faster lithium ion transmission and higher compaction density, resulting in improved cycle performance, rate performance, and volume energy density of the battery cell.
Implementation Method 1
the contact area between an electrolyte solution in the battery cell and the lithium-rich manganese-based material is increased, which facilitates the transmission of lithium ions
Data Source
AI summary
Provided are a positive electrode active material, a positive electrode plate, a battery cell, a battery and an electrical apparatus, which belongs to the technical field of secondary batteries. The positive electrode active material includes a lithium-rich manganese-based material and a lithium-containing phosphate, in which, the lithium-rich manganese-based material includes solid particles and hollow particles, the hollow particle including a shell and a cavity provided inside the shell. Both the rate performance and the volume energy density of the battery cell can be taken into consideration in the technical solution.