This technology orients the primary particles that form the secondary particles of a cathode active material for all-solid-state batteries into a radial rod-shaped structure extending from the center to the surface. This secures lithium-ion diffusion paths and suppresses microcracks caused by volume changes, thereby enhancing interface stability with the solid electrolyte.
Conventional cathode active materials for all-solid-state batteries suffer from randomly oriented primary particles, which lead to microcracks due to anisotropic volume changes during charging and discharging. This results in increased interface resistance with the solid electrolyte and hinders smooth lithium-ion diffusion into the secondary particles, ultimately degrading cycle life and electrochemical performance.
This technology arranges the primary particles on the surface of the secondary particles in a rod shape with their long axes pointing toward the center, and optimizes lithium-ion diffusion paths by increasing the a-axis/c-axis length ratio from the center to the surface. Additionally, a nickel concentration gradient—lower at the surface and higher at the center—is applied to reduce side reactions with the solid electrolyte while maintaining capacity. Applicable to high-nickel cathodes in next-generation all-solid-state cells using sulfide, halide, or oxide electrolytes, it delays contact loss at the solid-solid interface and is advantageous for long-term cycle capacity retention.
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