Uniform Bi–Sb Alloy Nanoparticles Synthesized from MOFs by Laser Metallurgy for Sodium-Ion Batteries

We report the design and synthesis of a bismuth metal–organic framework (MOF), MOF-836. This MOF is loaded with Sb salts in its pores and is used as the precursor for the production of Bi–Sb alloy nanoparticles by the nanoscale laser metallurgy method in the air. The resulting Bi–Sb alloy nanoparticles, Bi1–xSbx(from MOF-836), exhibit uniform particle sizes of 30 ± 10 nm, and their compositions are precisely controlled by tuning the content of Sb in MOF-836. These Bi–Sb alloys, along with the ones prepared from another Bi-MOF, CAU-7, were employed as anodes for sodium-ion batteries (SIBs). The nanosized Bi0.70Sb0.30(from MOF-836) alloys showed a specific capacity of 259.8 mAh g–1 at 200 mA g–1 after 500 cycles, and excellent cycling performance, capacity retention of 180.9 mAh g–1 at 1 A g–1 over 1000 cycles with a capacity loss of only 0.055% per cycle. This nanoscale laser metallurgy method using MOFs as precursors represents a new way to prepare alloy nanoparticles.