Metal selenides have been explored as promising sodium storage materials owing to their high theoretical capacity. However, sluggish Na⁺ diffusion and low electronic conductivity of selenides still hinder their practical applications. Herein, FeSe_2-xS_x microspheres have been prepared via a self-doping solvothermal method using NH₄Fe(SO₄)₂ as both the Fe and S source, followed by gas phase selenization. The density functional theory calculation results reveal that S doping not only improves the Na adsorption, but also lower the diffusion energy barrier of Na atoms at the S doping sites, at the same time enhance the electronic conductivity of FeSe_2-xS_x. The carbon-free nature of the FeSe_2-xS_x microspheres results in a low specific surface area and a high tap density, leading to an initial columbic efficiency of 85.6%. Compared with pure FeSe₂, such FeSe_2-xS_x delivers a high reversible capacity of 373.6 mAh·g⁻¹ at a high current density of 5 ​A·g⁻¹ after 2000 cycles and an enhanced rate performance of 305.8 mAh·g⁻¹ at even 50 ​A·g⁻¹. Finally, the FeSe_2-xS_x//NVP pouch cells have been assembled, achieving high energy and volumetric energy densities of 118 ​Wh·kg⁻¹ and 272 ​mWh·cm⁻³, respectively, confirming the potential of applications for the FeSe_2-xS_x microspheres.

由于其高理论容量，金属硒化物已被探索为有前途的钠储存材料。然而，硒化物的Na ⁺扩散缓慢和电子电导率低仍然阻碍了它们的实际应用。在此，FeSe _{2- x} S _x微球已通过使用NH ₄ Fe(SO ₄ ) ₂作为Fe源和S源，然后气相硒化的自掺杂溶剂热法制备。密度泛函理论计算结果表明，S掺杂不仅提高了Na的吸附，而且降低了Na原子在S掺杂位点的扩散能垒，同时增强了FeSe 2-的电子_电导率x S _x。_{FeSe 2- x} S _x微球的无碳特性导致低比表面积和高振实密度，导致初始库仑效率为 85.6%。与纯 FeSe ₂相比，这种 FeSe _{2- x} S _x^{在 5 A·g −1}的高电流密度下^{循环 2000 次后可提供 373.6 mAh·g −1}的高可逆容量和 305.8 mAh·的增强倍率性能g ⁻¹在甚至 50 A·g ⁻¹。最后，FeSe _{2- x} S _x//NVP 软包电池已经组装完成，分别实现了 118 Wh·kg ⁻¹和 272 mWh·cm ^{−3的高能量密度和体积能量密度，证实了 FeSe} _{2- x} S _x微球的应用潜力。