Atomic indium decorated graphene for dendrite-free sodium anodes towards high-energy-density sodium-metal batteries

Na metal batteries (SMBs) have emerged as a fascinating choice for large-scale energy storage. However, dendrite formation on Na metal anode has been acknowledged to cause inferior cycling stability and safety issues. Herein, we report the design of atomic indium-decorated graphene (In/G) to inhibit the growth of Na dendrites and substantially improve the stability of high-energy-density SMBs. Benefiting from the high-valence In-O-C configuration and evenly distributed sodiophilic sites, the In/G promotes uniform nucleation and in-plane growth of Na on the electrode surface, resulting in the intrinsic suppression of Na dendrites. Remarkably, the In/G@Na||Na batteries exhibit excellent long-term cyclability with 160 h at 8 mA cm⁻² and ultralow overpotential of 110 mV at 10 mA cm⁻². The Na₃V₂(PO₄)₃||In/G@Na full batteries show exceptionally high reversible discharge capacity of 61 mAh g⁻¹ at an ultrahigh rate of 40 C and extremely low capacity decay rate of only 0.021% per cycle over 300 cycles at 1 C. Therefore, this strategy provides a new direction for the development of next-generation high-energy-density SMBs.