Battery & Fuel Cell Technology

Biography

Biography: Taketoshi Matsumoto

Abstract

Si swarf is generated during slicing Si ingots to produce Si wafers for solar cells. The weight of Si swarf, i.e., industrial waste, is nearly the same as that of Si wafers. Si swarf and Si nanopowder produced by the ball and beads milling methods possesses flake-like shape with length smaller than a few μm and thickness thinner than 40 nm. We have applied Si nanopowder produced from swarf to Li ion batteries, fluorescent materials, a hydrogen generation material, and solar cells. In this study, Si has been applied to high capacity active materials for anodes in Li ion batteries. Si nanoparticles smaller than 150 nm are known to show good cyclability; while for larger Si particles, peeling-off of Si due to their volume change occurs during lithiation and delithiation, resulting in degradation of the cyclability. Si swarf is a promising low-cost material for mass production of Si anodes, while Si nanoparticles have been fabricated so far using high-cost processes such as CVD and laser ablation. Cyclability of a Si anode fabricated from Si swarf is improved by addition of 10-15 wt% fluoroethylene carbonate (FEC) to ethylene carbonate (EC)/diethylene carbonate (DEC)=1/1 electrolyte solutions with 1 M LiPF6. The solutions form a thin and stable solid-electrolyte interphase (SEI) layer, leading to decreases in the SEI resistance (R_SEI) and charge transfer resistance (R_ct). Carbon-coating (C-coating) on Si also improves the cyclability of the Si anode. Limitation of the delithiation capacity at 1500 mA h/g after deep lithiation at 0.01 V with a Li foil counter electrode also shows better cyclability than that for limitation of the lithiation capacity at 1500 mA h/g after deep delithiation at 1.5 V.

Recent Publications:

1. Matsumoto T, Kimura K, Nishihara H, Kasukabe T, Kyotani T, Kobayashi H (2017) Fabrication of Si nanopowder from Si swarf and application to high-capacity and low cost Li-ion batteries. J. Alloys Compd. 720: 529-540.

2. Kimura K, Matsumoto T, Nishihara H, Kasukabe T, Kyotani T, Kobayashi H (2017) Improvement of cyclability of Li-ion batteries using C-coated Si nanopowder electrode fabricated from Si swarf with limitation of delithiation capacity. J. Electrochem. Soc. 164: A995-A1001.

3. Kasukabe T, Nishihara H, Kimura K, Matsumoto T, Kobayashi H, Kyotani T (2017) Beads-milling of waste Si sawdust into high-performance nanoflakes for lithium-ion batteries. Sci. Rep. 7: 42734-1-10.

4. Matsumoto T, Maeda M, Kobayashi H (2016) Photoluminescence enhancement of adsorbed species on Si. Nanoscale Res. Lett. 11:  7-1-6.

5. Matsumoto T, Maeda M, Furukawa J, Kim W-B, Kobayashi H (2014) Si nanoparticles fabricated from Si swarf by photochemical method. J. Nanopart. Res. 16: 2240-1-7.

6. Maeda M, Imamura K, Matsumoto T, Kobayashi H (2014) Fabrication of Si swarf and application to solar cells. Appl. Surf. Sci. 312: 39-42.