Diamane Facilitated the Stability of Sodium Metal Anodes

Sodium metal anodes hold great promise for next-generation batteries due to their high theoretical capacity and low working potential, yet notorious Na dendrites impose tremendous safety concerns. Here, diamane (two-dimensional diamond) nanoflakes modulating the polypropylene (PP) separator are implemented to address this issue. The diamane physically exfoliated from commercially available diamond exhibits its superiority in suppressing the Na dendrites formation by stable sp3 carbon surface. Using the PP/diamane separator, Na metal anodes demonstrate exceptional stability for over 1000 h at an ultrahigh current density of 20 mA cm–2. Notably, the separator also ensures stable cycling of Na metal anodes at an elevated temperature of 60 °C. Encouragingly, the full cell of Na||PP/diamane||Na3V2(PO4)3@C delivers a high capacity of 81.6 mAh g–1 with a minimal decay of 0.003% per cycle after 1000 cycles. These results provide a promising strategy for realizing stable Na metal anodes via the incorporation of diamane nanoflakes.