Nanosized electrodeposited 62 atom % Sn-Ni alloy was tested to highlight the effects of volume changes on the cycling life of the electrode during lithiation and delithiation. X-ray diffraction showed that the Ni 3Sn4 was the main phase of the as-deposited alloy. A unique feature of the 62 atom % Sn-Ni is that it exhibited a capacity recovery upon cycling. When cycled galvanostatically, the Sn62Ni38 offers low capacity fade while reversibly incorporating lithium up to 600 mAh/g. At the first charge LiSn alloy phases are formed. This led to volume expansion of the electrode causing the formation of cracks. At the following cycles the Ni3Sn4, phase was restored and preserved over extensive cycling revealing the reversibility of the reaction between Ni 3Sn4, and Li+. As to the reasons of the capacity recovery noticed with this alloy, scanning electron microscopy images provided evidence of modifications of the surface condition accompanying a volume change during cycling. The chemical diffusion coefficient (D Li) value determined from electrochemical impedence spectroscopy measurements during lithium insertion was within 10-9 to 10 -10 cm2 s-1.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry