Micron-Sized Nanoporous Antimony with Tunable Porosity for High-Performance Potassium-Ion Batteries

Potassium-ion batteries (KIBs) are considered favorable candidates for post-lithium-ion batteries, a quality attributed to their low cost, abundance as a resource, and high working potential (−2.93 V for K+/K). Owning to its relatively low potassiation potential and high theoretical capacity, antimony (Sb) is one of the most favorable anodes for KIBs. However, the large volume changes during K–Sb alloying and dealloying causes fast capacity degradation. In this report, nanoporous Sb (NP-Sb) is fabricated by an environmentally friendly vacuum-distillation method. The NP-Sb is formed via evaporating low-boiling-point zinc (Zn). The byproduct Zn can be recycled. It is further found that the morphology and porosity can be controlled by adjusting Zn–Sb composition and distillation temperature. The nanoporous structure can accommodate volume expansion and accelerate ion transport. The NP-Sb anode delivers an improved electrochemical performance. These results suggest that the vacuum-distillation method may provide a direction for the green, large-scale, and tunable fabrication of nanoporous materials.