Quasi-Spherical Spinel Cathode Oxide for Crack-Resistant Li-Ion Batteries
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Solution Overview
Problem
Conventional spinel lithium manganese oxide is prone to cracking and stress corrosion due to its sharp crystal morphology, which affects the electrochemical performance of lithium-ion batteries.
Innovation Solution
A spinel-type lithium and manganese containing composite oxide with a quasi-spherical morphology is developed, which has a chemical composition of Li1+xMyMn2-yO4-k, where −0.1≤x≤0.2; 0≤y≤0.3; 0≤k≤0.2; and M includes at least one of B, Na, Mg, Al, Si, P, K, Ti, V, Cr, Fe, Co, Ni, Cu, Zr, Mo, W, and Te. The crystal grains have a continuous curved surface with a limited number of finite surfaces, reducing stress concentration and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spinel lithium manganese oxide with sharp crystal morphology is used, then cost advantage and safety performance are improved, but cracking and stress corrosion occur affecting electrochemical performance
Solution Approach 1:
The patent applies spheroidality by transforming the sharp crystal morphology into a quasi-spherical shape with rounded surfaces. The crystal grains are designed to have a diameter of 5-20 μm with spherical geometry, which eliminates stress concentration points and prevents cracking while maintaining the spinel structure's inherent safety advantages
Solution Approach 2:
The patent changes physical parameters including crystal grain size (5-20 μm), morphology (quasi-spherical), and surface characteristics (rounded surfaces). These parameter changes transform the material from sharp-crystalline to spherical granules, improving mechanical strength and cracking resistance while preserving electrochemical performance
2Ease of manufacture
If spinel-structured lithium manganese oxide is used, then cost advantage is improved, but crystal grain cracking and stress corrosion affect service life
Solution Approach 1:
The spherical morphology with rounded surfaces prevents stress concentration and cracking, directly extending the service life of the battery. The quasi-spherical crystal grains maintain structural integrity during charge-discharge cycles, reducing degradation and prolonging operational duration
Solution Approach 2:
The rounded spherical surfaces act as a cushioning mechanism that beforehand prevents stress concentration and cracking. By designing the crystal grains with spherical geometry and smooth surfaces, the material is pre-protected against the mechanical stresses that would otherwise cause premature failure
Data Source
AI summary
A spinel-type lithium and manganese containing composite oxide has a chemical composition of Li1+xMyMn2-yO4-k, where −0.1≤x≤0.2; 0≤y≤0.3; 0≤k≤0.2. M includes at least one of B, Na, Mg, Al, Si, P, K, Ti, V, Cr, Fe, Co, Ni, Cu, Zr, Mo, W, and Te. Crystal grains of the spinel-type lithium and manganese containing composite oxide have a quasi-spherical morphology. A surface of a single crystal grain is formed by a continuous curved surface connected to a finite surface with a profile circumscribed by the continuous curved surface, or is a continuous curved surface. A quantity of observable finite surfaces with the profile circumscribed by the continuous curved surface in an SEM image of a single crystal grain is ≤5. A ratio of a diameter dA of the finite surface with the profile circumscribed by the continuous curved surface to a diameter dV of the crystal grain satisfies dA/dV≤0.5, optionally dA/dV≤0.3.