| dc.description.abstract | The topic of this thesis is silicon anodes for lithium-ion batteries. The aim of this thesis
is to compare three different types of silicon powders for use in lithium-ion batteries - a
micron-sized powder (Silgrain e-Si 400), a nano-sized powder (Sigma-Aldrich nano-Si) and
a type of silicon kerf (99.5% Si Resitec). The silicon powders are compared based on physical
characteristics, rate performance, medium-term cycling performance and electrode resistance.
The silicon powders were physically characterized by x-ray diffraction and the Brunauer-
Emmett-Teller method. Silicon electrodes were prepared by tape casting and assembled into
either coin cells or three-electrode cells in half-cell congurations. The silicon electrodes in
coin cells were evaluated through a rate test and a 50 cycle test. The electrode resistance
was evaluated by electrochemical impedance spectroscopy of the three-electrode cells.
All the silicon powders were crystalline, but had different specic surface areas. Sigma-
Aldrich nano-Si powder showed considerably higher surface area than Silgrain e-Si 400
and 99.5% Si Resitec. The performance was evaluated based on delithiation capacity. The
electrodes with Silgrain e-Si 400 and 99.5% Si Resitec performed slightly better than the
electrodes with Sigma-Aldrich nano-Si through 50 cycles. The test did not show signicant
capacity fade after 50 cycles for none of the three silicon powders. All three silicon powders
performed similarly through the rate test. No reliable conclusion was drawn from the
electrochemical impedance spectroscopy tests with respect to electrode resistance. | |
