Antimony trisulfide (Sb₂S₃) is a prospective electrode material for lithium-ion batteries (LIBs) because of its thermal stability, low price, and high specific capacity. However, the commercialization of Sb₂S₃ as an anode material is greatly hindered by its poor electronic conductivity and massive volume variation during charge/discharge cycles. Moreover, growing demand in reducing greenhouse gas emission requires the material preparation process to be pollution free and highly energy efficient. Herein, we introduce, for the first time, an eco-friendly and highly efficient one-step annealing method to construct a three-dimensional (3D) flexible conductive network and buffer matrix for N-doped Sb₂S₃-carbon fibers (NSSCs) as a high-performance anode. It is assembled by mixing sulfur and antimony in the atomicity level with a stoichiometric ratio as the electrospinning precursor and then annealed in a sealed quartz tube to assure the high atom utilization of nitrogen and sulfur. Benefiting from the 3D structure and compositional advantages, the NSSC electrode with improved conductivity and carbon buffer matrix exhibits superior Li-storage performance. As a result, this work not only promotes the commercialization of antimony trisulfide but also points out a general eco-friendly method, which can be widely applied to synthesize a variety of flexible metal sulfides and metal nitrides with high atom utilization and zero discharge.