Thanks to their versatile properties and excellent electrical conductivity, MXenes have become attractive materials for alkali metal-ion batteries. However, their capacity is limited to low values due to the intercalation mechanism, which hinders their competitiveness in the rapidly evolving battery research community.

Antimony offers a promising theoretical sodiation capacity characterized by an alloying reaction. However, its main drawback in battery applications is the significant volume changes during cycling, leading to electrode fracture and pulverization, thereby reducing electrochemical performance. Combining antimony with MXene can synergistically optimize the electrochemical system to mitigate antimony’s capacity fading while leveraging MXene’s charge storage capability.

This study focused on varying synthesis parameters and material design strategies to develop optimized antimony/MXene hybrid electrodes for high-performance sodium-ion batteries. The best performance was achieved not by maximizing antimony content, using the smallest nanoparticles, or maximizing the distance between MXene layers, but by ensuring the most homogeneous distribution of antimony and MXene.

Consequently, the electrode with 40% MXene (unexpanded and leached with 5% HF) and 60% antimony synthesized on MXene surfaces proved to be optimal. This hybrid material demonstrated a high reversible capacity of 450 milliampere-hours per gram at a current rate of 0.1 ampere per gram, with a capacity retention of approximately 96% after 100 cycles. In addition to its cycling stability, this material exhibited a high capacity even at high current rates, specifically 365 milliampere-hours per gram at 4 amperes per gram. In situ X-ray diffraction (XRD) measurements and post-mortem analysis were employed to investigate the reaction mechanism.