Heteroatom-doped carbon inlaid with Sb2X3 (X = S, Se) nanodots for high-performance potassium-ion batteries

Antimony-based materials with high theoretical capacity have been considered as a promising anode materials for potassium-ion batteries (PIBs). Unfortunately, the large volume expansion leads to rapid capacity fading and poor rate capability. In this work, Sb2S3 (Sb2Se3) nanodots/carbon composites are constructed through pyrolysis and co-sulfurization (selenylation) process of sodium stibogluconate for the first time. In the composite, Sb2S3 (Sb2Se3) nanodots with diameters of 15-25 nm are uniformly inlaid into S(Se)-doped carbon skeleton. Notably the ultrafine nanodots can remarkedly shorten the ions diffusion distance with enhanced kinetic process. Also the S(Se)-doped carbon would provide the stable structure support and conducive path. When applied as the anode for PIBs, they all show satisfactory potassium-storage properties in terms of high reversible capacity and superior rate capability, especially the excellent electrochemical performances of Sb2Se3 nanodots/carbon with a reversible capacity of 312.03 mAh g(-1) at 1000 mA g(-1) after 200 cycles, which can be attributed to the synergistic effect of nanodots and doped carbon, minimizing potassiation-induced deformations and facilitating the reversible adsorption of K ions. More importantly, the volume changes during the K+ intercalation/deintercalation process have been analyzed in details, which is well consistent with the result of electrochemical performance, as expected.