Fluorinated Aluminum Foam for Dendrite-Free Na Metal Anodes

Sodium metal batteries have attracted extensive attention because of the high availability and energy density of Na; however, the practical application of these batteries is significantly plagued by dendritic growth. Aluminum metal has a unique advantage as a current collector for sodium metal anodes because of its low density and low cost. However, problems with dense aluminum oxide mean its application in sodium metal anodes has seldom been studied. In this study, aluminum foam was fluorinated by a facile method and compounded with sodium metal at high temperatures to prepare a sodiophilic aluminum foam@sodium electrode (NaHFAl). Because of the sodiophilic surface, NaHFAl achieves a non-dendritic deposition morphology and markedly reduced voltage hysteresis in symmetric cells for over 2200 h. The NaHFAl/carbonate electrolyte/sulfurized polyacrylonitrile (SPAN) cell exhibited excellent cycle performance, with a capacity retention of 68% after 800 cycles. Our work provides an easily scalable and cost-effective approach for the development of high-performance sodium metal anodes.