Carbon-Coated Polyanion Cathode Particles for Dense Electrodes
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Solution Overview
Problem
Lithium transition metal compounds with a polyanion structure face challenges in densifying active material layers, resulting in insufficient discharge capacity per volume in energy storage devices.
Innovation Solution
A granular active material particle is developed, where a lithium transition metal compound with a polyanion structure is coated with a carbon material, and exhibits a minimal change in particle size under pressure, allowing for the formation of a high-density active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium transition metal compound having a polyanion structure is used as an active material, then the energy storage device can operate with high energy density, but the active material layer cannot be sufficiently densified, resulting in low discharge capacity per volume
Solution Approach 1:
The invention changes the physical and chemical parameters of the active material particle by coating it with a specific carbon material layer, transforming the surface properties to enable better densification during electrode formation while maintaining the core polyanion structure's electrochemical performance
Solution Approach 2:
The invention creates a composite structure where a lithium transition metal compound core is coated with a carbon material layer, combining the high energy density benefits of polyanion structures with the densification capabilities enabled by the carbon coating
Data Source
AI summary
An active material particle according to one aspect of the present invention is a granular material in which a particle containing a lithium transition metal compound having a polyanion structure is coated with a carbon material, and has an amount of change in particle size of 1.1 nm or less when pressurized from 20 mN to 100 mN.