High-rate operando XRD studies on conversion/alloying materials (CAMs) as anodes in Na-ion batteries

Conversion/alloying materials (CAMs) as anodes for Na-ion batteries (NIBs) offer higher capacities than conventional intercalation materials but struggle with stability over many cycles. Their complex cycling mechanism, undergoing through a series of transformations combining crystalline and amorphous phases, make CAMs challenging to understand on the basis of chemical structures even with the most informative operando techniques. We have recently observed that Sb-based CAMs have surprisingly high capacity at high charge rates, and preliminary operando XRD results suggest that this may be because of different cycling mechanisms compared to slower charge rates, suggesting that kinetics plays a crucial role in the formation of certain phases during cycling. Thus, this experiment will focus on elucidating the main structural differences in the reaction mechanism of a selection of Sb-based CAMs and their Bi- and Sn-analogues as a function of the applied cycling rates with operando XRD.