The unique morphology and phase assemblage of the Sb–rGO composite material were achieved through a sequential synthesis process. Initially, reduced graphene oxide (rGO) was dispersed in ethanol, followed by the addition of antimony chloride (SbCl3) dissolved in ethanol. This mixture was stirred continuously for at least 10 hours at room temperature. Subsequently, an ammonia solution was added, and the resulting mixture was stirred for an additional 12 hours under the same conditions. After allowing the solution to settle and dry, the obtained residue was rapidly heated to 700°C for 2 hours in an argon atmosphere, yielding the desired composite with the required structural and phase characteristics. An electrode fabricated from the developed Sb–rGO composite was tested as an anode material for sodium-ion batteries (SIBs), demonstrating a high sodium storage capacity of approximately 550 mAh/g at a current density of 0.2 A/g. The material exhibited excellent capacity retention of about 97% after 150 charge–discharge cycles at the same current density. Moreover, it showed outstanding rate capability, retaining over 86% of its capacity when the current density was increased from 0.1 A/g to 2 A/g, delivering a capacity of approximately 490 mAh/g even at the highest tested rate.