The Na (de)insertion reactions in these kind of compounds can proceed via one of the following routes: intercalation, conversion or alloying. Apparently, we found thatMoSe2 electrode operates via anomalous mutli-way mechanism where Na (de)insertion reaction proceeds sequentially via all three scenarios. By combination of variety operando and ex-situ XRD and XAS studies we observed unexpected phenomena of Se precipitation which leads to the additional alloying reaction.
MoSe2
Recently we examine, quite unique material – MoSe2belonging to transition-metal chalcogenides group which have gained special attention as potential anodes for Na-ion batteries.
Figure 1. XANES spectra (a,b,c) with contour map (d) for sodium K-edge registered during 1st discharge/charge cycle along with voltage characteristics for measured Na|MoSe2 cell. For better visibility the XANES spectra for selected energy range are included.
Figure 2. Schematic representation of sodium (de)insertion mechanisms taking place during discharge/charge cycles of Na|MoSe2 cell along with its voltage characteristics for 1st and 2nd discharge/charge cycle.
