US20260204546
2026-07-16
Electricity
H01M4/364
The patent application describes an electrode active material composite particle that consists of silicon particles and a binder. The binder is a combination of fluorine-based and non-fluorine-based polymers. Notably, the composition varies within the particle: the fluorine-based polymer is more concentrated in the inner region, while the non-fluorine-based polymer is more prevalent in the outer region. This unique distribution aims to enhance battery performance by reducing irreversible capacity.
The disclosure focuses on advancements in electrode active material composite particles, their production methods, and applications in battery technology. Previous technologies often rely on silicon particles and fluorine-based polymers as binders, but these have limitations in terms of irreversible capacity. The invention seeks to address these issues by optimizing the polymer distribution within the composite particles.
Key improvements include the strategic placement of polymers within the composite particle. The inner region's higher fluorine-based polymer content and the outer region's higher non-fluorine-based polymer content help mitigate reactions between fluorine-based polymers and lithium ions, thereby reducing irreversible capacity. The application specifies that the fluorine-based polymer content should not exceed 30 parts by mass per 100 parts of silicon particles, and the non-fluorine-based polymer should be 15 parts by mass or less.
The electrode composite, incorporating these composite particles, can be utilized in batteries to improve their efficiency. The strategic polymer arrangement within the particle reduces the potential for undesirable chemical reactions, enhancing battery longevity and performance. This makes the technology particularly useful for high-capacity batteries where maintaining structural integrity and capacity over cycles is crucial.
The production involves creating a first slurry with silicon particles and a fluorine-based polymer, followed by spray drying to form preliminary particles. A second slurry is then prepared with these particles and a non-fluorine-based polymer, which is also spray dried. This two-step process ensures the desired polymer distribution within the composite particles, contributing to the improved battery characteristics.