Two-dimensional NbSSe as anode material for low-temperature sodium-ion batteries

Sodium ion batteries performance at low temperature is extremely restricted by the sluggish kinetics of sodium ions diffusion within active materials and interface. The strategy of inducing interlayer anionic ligands in two-dimensional NbSSe nanoplates is employed to consolidate the interlayer band gap and optimize the electronic structure. It combines complementary benefits from two kinds of anionic ligands with high conductivity and good affinity with sodium ions at low temperature. The explored two-dimensional NbSSe nanoplates can provide an acceptable rate and lifespan electrochemical performance, delivering a high reversible capacity of 136 mAh g−1 at 0 °C with the 92.67% retention after 500 cycles at 0.2 C. The totally sodium storage capacity are contributed from the combination of capacitive and diffusion behaviours. The sodium ion diffusion coefficients are in the range of 3.23 × 10-13 to 4.47 × 10-12 at 0 °C. The diffusion apparent activation energy is 54.92 kJ mol−1 and the activation energy is 65.97 kJ mol−1. The explored two-dimensional NbSSe nanoplates can extend the sodium ion battery application field, particularly at low temperatures.