Two-dimensional layered In2P3S9: A novel superior anode material for sodium-ion batteries

Developing reliable and efficient anode materials is essential for the successfully practical application of sodium-ion batteries. Herein, employing a straightforward and rapid chemical vapor deposition technique, two-dimensional layered ternary indium phosphorus sulfide (In2P3S9) nanosheets are prepared. The layered structure and ternary composition of the In2P3S9 electrode result in impressive electrochemical performance, including a high reversible capacity of 704 mA h g−1 at 0.1 A g−1, an outstanding rate capability with 425 mA h g−1 at 5 A g−1, and an exceptional cycling stability with a capacity retention of 88% after 350 cycles at 1 A g−1. Furthermore, sodium-ion full cell also affords a high capacity of 308 and 114 mA h g−1 at 0.1 and 5 A g−1. Ex-situ X-ray diffraction and ex-situ high-resolution transmission electron microscopy tests are conducted to investigate the underlying Na-storage mechanism of In2P3S9. The results reveal that during the first cycle, the P–S bond is broken to form the elemental P and In2S3, collectively contributing to a remarkably high reversible specific capacity. The excellent electrochemical energy storage results corroborate the practical application potential of In2P3S9 for sodium-ion batteries.