Comparing the Performance of Different Silicon Powders for Use in Lithium-Ion Batteries
Master thesis
Permanent lenke
http://hdl.handle.net/11250/2576496Utgivelsesdato
2018Metadata
Vis full innførselSamlinger
Sammendrag
The topic of this thesis is silicon anodes for lithium-ion batteries. The aim of this thesisis to compare three different types of silicon powders for use in lithium-ion batteries - amicron-sized powder (Silgrain e-Si 400), a nano-sized powder (Sigma-Aldrich nano-Si) anda type of silicon kerf (99.5% Si Resitec). The silicon powders are compared based on physicalcharacteristics, 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 intoeither coin cells or three-electrode cells in half-cell congurations. The silicon electrodes incoin cells were evaluated through a rate test and a 50 cycle test. The electrode resistancewas 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 400and 99.5% Si Resitec. The performance was evaluated based on delithiation capacity. Theelectrodes with Silgrain e-Si 400 and 99.5% Si Resitec performed slightly better than theelectrodes with Sigma-Aldrich nano-Si through 50 cycles. The test did not show signicantcapacity fade after 50 cycles for none of the three silicon powders. All three silicon powdersperformed similarly through the rate test. No reliable conclusion was drawn from theelectrochemical impedance spectroscopy tests with respect to electrode resistance.