Enhanced stability of sodium storage exhibited by carbon coated Sb2S3 hollow spheres

Antimony sulfide (Sb2S3) has been shown as a promising candidate for sodium ions batteries, in considering the gravimetric energy density and high theoretical capacity. Hollow-sphere Sb2S3 coated with carbon are successfully designed through Oswald ripening process. The Sb2S3/C utilized as SIBs anode displays excellent electrochemical properties, delivering a high charge capacity of 693.4 mAh g−1 at 0.2 A g−1 between 0.01 and 3.0 V (vs. Na+/Na). Its reversible capacity can keep 545.6 mAh g−1, with a retention of ∼80% after 100 cycles. Even the current densities return from 6.4 to 0.2 A g−1, the Sb2S3/C still maintains 550.8 mAh g−1 after 70 cycles. Combining the large void space with carbon layer, the advantages are noticed when the increased electrolyte penetration area, improved electronic conductivity and shortened Na+ diffusion length are attained concurrently, resulting in the excellent specific capacity and cycling stability. The study provides an effect strategy in improving the electrochemical performances of metal sulfides as anode for SIBs.