SAXS/WAXS studies on morphology of alloying anodes for Na-ion batteries

Alloying anode materials for metal-ion batteries provide higher capacity than traditional intercalation materials, at the cost of cycle stability. Many parameters can affect their lifetime and performance in a battery, including particle size and size of the pores in the electrode. With increasing particle size, diffusion limits the progress of chemical reactions. Larger pore size can improve ion diffusion at a cost of lower energy density. Small-angle X-ray scattering (SAXS) is a tool to investigate nanostructural changes occurring in a short range, which are complementary to the atomic scale, long range information obtained with wide-angle Xray scattering (WAXS). We will study the changes in porosity and particle size for Sn, Sb and Bi anode materials during cycling in Na-ion batteries. By measuring these parameters during battery operation, we aim to get a better understanding of morphological changes during cycling, and find the optimal balance between porosity and particle size.