Excellent sodium metal deposition enabled by three-dimensional porous structures with natrophilic Ni-Sn alloy

Na metal has long been an ideal potential anode material for sodium secondary batteries due to its own superiority; however, the Na dendrite problem during cycling makes it face a great obstacle in application. Here, we grow sodiophilic thin film materials with tin and nickel-tin components uniformly on three-dimensional nickel foam (3D-Ni) to obtain a 3D sodiophilic composite framework (namely 3D-NiSn) using a reproducible and mass-produced electrodeposition strategy. The combination of sodiophilic film (NiSn) and 3D porous framework could lower nucleation overpotential of Na and accelerate ions diffusion, hence inducing the uniform deposition and reversible stripping of sodium and inhibiting the growth of Na dendrites, which makes the 3D-NiSn/Na composite anode exhibit good performance compared to 3D-Ni/Na and Na-foil. The symmetrical cells with 3D-NiSn/Na can maintain up to 2500 h at 2 mA cm−2 and 1 mAh cm−2 with a low overpotential of around 30 mV during the whole cycling process. Additionally, the 3D-NiSn/NaǁNa3V2(PO4)3 full cells deliver good cycle stability with a high specific capacity of around 98.1 mAh g−1 at 3C for over 600 cycles. This work provides an idea for constructing low-cost and commercially available Na metal electrodes toward high-performance SIBs.