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4608 |
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Effect of multi-pass coatings on surface structure of cold sprayed Si coatings |
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Junichi Nakamura* / Shinshu University, Japan Hideyuki Saito / Shinshu University, Japan Kyohei Fujita/ Shinshu University, Japan Kazuhiko Sakaki/ Shinshu University, Japan |
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[Abstract] Si coatings are one of the most promising anode materials for lithium ion battery. Si coated Cu anodes by cold spray technique were studied to thicken their thickness and to improve their dense structure. Desirable thickness of Si coatings for anode is 5 to 10¼m. In spite that the thickness of cold sprayed Si coatings by 1 pass operation is only 2 to 3¼m. As for starting Si powders, average particle size is 5¼m. Coated Si layers was consisted by comparatively small particles less than 5¼m and there remained many small pits. To thicken the coatings, 2 pass or 3pass operations are performed. By 2 pass coatings, cold sprayed Si powders tend to not accumulate on pre-stuck Si particles rather than fulfil the small pits. That means it is difficult to thicken coating thickness by cold spray techniqueHowever their dense structures are improved. Surface morphologies, accumulated Si particles and fulfilled small Si particles were studied by SEM observation and photo image layer analysis. Thus coated Si-Cu foils were assembled to CR2032 type Li ion batteries and charge/discharge characteristics were. experimented. The 2 pass coated anode plate showed excellent charge/discharge characteristics. |