Understanding Desalination Batteries Across Scales via High-Energy XRD

Desalination batteries (DBs) are a promising electrochemical technology for energy-efficient water desalination by selectively extracting ions from water via faradaic electrodes. However, their practical implementation is hindered by limited understanding of ion insertion mechanisms, degradation processes, and the effect of artificial solid electrolyte interphases (ASEI). We aim to obtain knowledge by investigating manganese oxide and iron phosphate electrodes using operando high-energy XRD (HEXRD) in realistic flow-by DB reactors. We will investigate the behavior of LiMn2O4, Na0.44MnO2 and LiFePO4 with LiNbO3 and Li3PO4 ASEIs as intercalation electrodes in both standard Li/Na salt solutions as well as synthetic and real seawater environments. The outcomes will yield insights into the ion intercalation mechanisms within DB electrodes, their degradation and the benefits of the ASEI, spanning atomic to full electrode scales. Our findings will inform rational design of improved DBs.