Construction of Ultrastable Ultrathin Black Phosphorus Nanodisks Hybridized with Fe3O4 Nanoclusters and Iron (V)‐Oxo Complex for Efficient Potassium Storage

The practical application of metalloid black phosphorus (BP) based anodes for potassium ion batteries is mainly impeded by its instability in air and irreversible/sluggish potassium storage behaviors. Herein, a 2D composite is purposefully conceptualized, where ultrathin BP nanodisks with Fe₃O₄ nanoclusters are hybridized with Lewis acid iron (V)-oxo complex (FC) nanosheets (denoted as BP@Fe₃O₄-NCs@FC). The introduced electron coordinate bridge between FC and BP, and hydrophobic surface of FC synergistically assure that BP@Fe₃O₄-NCs@FC is ultrastable in humid air. With the purposeful structural and componential design, the resultant BP@Fe₃O₄-NCs@FC anode is endowed with appealing electrochemical performance in terms of reversible capacity, rate behavior, and long-duration cycling stability in both half and full cells. Furthermore, the underlying formation and potassium-storage mechanisms of BP@Fe₃O₄-NCs@FC are tentatively proposed. The in-depth insights here will provide a crucial understanding in rational exploration of advanced anodes for next-generation PIBs.