Multi-Cavity Cathode Material for High-Power Li-Ion Cycle Life
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Solution Overview
Problem
Lithium ion battery positive electrode materials with high power output characteristics face challenges in maintaining strength and cycle service life due to poor structural integrity, leading to rapid deterioration and pulverization during charge and discharge processes.
Innovation Solution
A positive electrode material with a multi-cavity structure is developed, formed by aggregating primary particles that grow in an oriented manner to form supporting structures, enhancing strength and reducing impedance, achieved through a method involving co-precipitation and sintering of Ni, Co, and Mn compounds with a lithium source and optional elements like W, Zr, or Ti.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the grain size of the material is decreased to increase contact area with electrolyte, then the power output is improved, but excessive fine powder is generated during charge and discharge process, deteriorating service life
Solution Approach 1:
The positive electrode material is segmented into a hierarchical structure consisting of a core particle and multiple cavity structures distributed throughout. This segmentation increases the effective contact area with electrolyte while maintaining overall particle integrity, allowing improved power output without generating excessive fine powder during charge-discharge cycles.
Solution Approach 2:
Different regions of the positive electrode material have different structural characteristics: the core provides structural stability, while the cavities provide high surface area for electrochemical reactions. This local differentiation allows the material to simultaneously achieve high power output through increased contact area and long service life through maintained structural integrity.
2Power
If a hollow structure is prepared to increase contact area with electrolyte, then power performance is improved to some extent, but the strength of the material is deteriorated, causing fracture and pulverization during rolling process and charge-discharge process
Solution Approach 1:
The positive electrode material employs a composite structure combining a dense core with distributed cavity structures. The core provides mechanical strength and structural stability, while the cavities contribute to increased contact area with electrolyte. This composite architecture resolves the contradiction between improving power performance and maintaining material strength, preventing fracture and pulverization during processing and charge-discharge cycles.
3Power
If a loose and porous structure with large space between particles and penetration holes is created to increase contact area and reduce reaction resistance, then the material exhibits large specific surface area, but the structure has poor strength under pressure, being prone to pulverize and deform during battery fabrication process
Solution Approach 1:
Rather than creating a uniformly loose and porous structure, the invention segments the porosity into discrete cavity structures within a denser matrix. This segmentation maintains compressive strength by preserving material continuity while still providing adequate contact area with electrolyte through the distributed cavities, preventing pulverization and deformation during battery fabrication.
Solution Approach 2:
The structure exhibits local quality differentiation where cavities are strategically distributed to provide electrochemical activity zones, while the surrounding matrix maintains sufficient density and strength. This local differentiation allows the material to achieve good power performance through increased surface area while maintaining adequate compressive strength to withstand battery fabrication processes.
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 multi-cavity structure significantly increases contact area with the electrolyte, reduces impedance, and enhances the cycle performance and power performance of the positive electrode material, maintaining desirable strength and extending its service life.
Implementation Method 1
the multi-cavity structure significantly increases contact area with the electrolyte, reduces impedance
Implementation Method 2
some of the primary particles grow in an oriented manner to form supporting structures, the supporting structures overlap each other inside the positive electrode material
Data Source
AI summary
The present disclosure relates to the technical field of positive electrode materials of lithium ion batteries. Disclosed a positive electrode material having a multi-cavity structure and a preparation method therefor, and a lithium ion battery. The positive electrode material is formed by aggregation of a plurality of primary particles, and some of the primary particles grow in an oriented manner to form supporting structures, the supporting structures overlapping each other inside the positive electrode material to form a plurality of cavities. The particle strength of the positive electrode material is significantly improved, so that the positive electrode material has the advantage of a long service life. In addition, the impedance of the positive electrode material is reduced, thereby improving the power performance of the positive electrode material.