A New rGO‐Overcoated Sb 2 Se 3 Nanorods Anode for Na + Battery: In Situ X‐Ray Diffraction Study on a Live Sodiation/Desodiation Process

Sodium ion batteries (SIBs) are a promising alternative to lithium ion batteries for a broader range of energy storage applications in the future. However, the development of high‐performance anode materials is a bottleneck of SIBs advancement. In this work, Sb 2 Se 3 nanorods uniformly wrapped by reduced graphene oxide (rGO) as a promising anode material for SIBs are reported. The results show that such Sb 2 Se 3 /rGO hybrid anode yields a high reversible mass‐specific energy capacity of 682, 448, and 386 mAh g −1 at a rate of 0.1, 1.0, and 2.0 A g −1 , respectively, and sustains at least 500 stable cycles at a rate of 1.0 A g −1 with an average mass‐specific energy capacity of 417 mAh g −1 and capacity retention of 90.2%. In situ X‐ray diffraction study on a live SIB cell reveals that the observed high performance is a result of the combined Na + intercalation, conversion reaction between Na + and Se, and alloying reaction between Na + and Sb. The presence of rGO also plays a key role in achieving high rate capacity and cycle stability by providing good electrical conductivity, tolerant accommodation to volume change, and strong electron interactions to the base Sb 2 Se 3 anode.