Small Molecule‐Assisted Thermal Radiation Synthesis of Super‐Sb Toward Ultrafast and Ultrastable Sodium Storage

The nonequilibrium synthetic conditions of the unique molecule-assisted thermal radiation (MTR) method convert small-molecule additives into N/S co-doped carbonaceous layers with abundant surface defects, ensuring the formation and stabilization of Sb nanoparticles. Additionally, the ultrasmall nanostructure exhibits higher resistance against sodiation-induced stress compared to the bulk structure.

Abstract

Nanostructure engineering of alloying-type anodes is a key approach to achieving high electrochemical performance in sodium-ion batteries (SIBs). Despite intensive efforts in traditional calcination methods, synthesizing high-quality nanomaterials while maintaining ultrafine and homogeneous nanostructure under high temperature remains a key challenge. Herein, a one-step small molecule-assisted thermal radiation (MTR) method that fabricates ultrafine Sb nanoparticles with uniform dispersion across heteroatom-doped carbon supports (Super-Sb) is reported. This MTR method features the nonequilibrium synthetic conditions induced by ultrafast heating/cooling rate. Additionally, in situ, high-temperature synchrotron X-ray diffraction (SXRD) characterization of the MTR synthetic process demonstrates that the formation and stabilization of ultrasmall Sb nanoparticles can be ascribed to the simultaneous thermolysis of small-molecule additives into defect-rich carbon nanosheets. The as-obtained Super-Sb nanocomposite exhibits superior sodium-ion storage performance in terms of ultralong cycling stability of 15 000 cycles at 20.0 A g⁻¹ and ultrahigh rate capability of 152.8 mAh g⁻¹ at 50.0 A g⁻¹. Furthermore, in situ laboratory XRD and finite element analysis (FEA) demonstrate the structural advantages of the ultrafine nanoparticles in stress-buffering effect. This study provides an effective strategy to manufacture high-performance and high-quality energy-storage nanomaterials for advanced SIBs.