Elucidating dual-defect mechanism in rhenium disulfide nanosheets with multi-dimensional ion transport channels for ultrafast sodium storage

Abstract The sodium-ion storage property in two-dimensional transition metal dichalcogenides (TMDs) is still seriously confined due to the lacking of efficient pathways for Na+ insertion, which enlightens the construction of multi-dimensional ion channels a necessary. Herein, we prepared interlayer defect, sulfur vacancy-contained ReS2 nanosheets on porous nitrogen-doped carbonized bacterial cellulose (dr-ReS2-x/NCBC). In such dual-defect configuration, the interlayer defects provide interconnected in-plane/interlamination channels for offering extra pathways of Na+ insertion/extraction and shortening ionic diffusion distance, while the sulfur vacancy could further enhance the electronic conductivity and induce more active sites for Na+ storage. Therefore, the dr-ReS2-x/NCBC anode displays an enhanced rate capacity (231.2 mAh g−1 at 5 A g−1) and a good cycling stability (187.3 mAh g−1 at 5 A g−1 after 500 cycles). Furtherly revealed by density functional theory calculations, the sodium-ion storage property is attributed to its negatively shifted binding energy for sodium ions (from −0.771 to −1.791/-1.244 eV), and alleviated structural change (from 5.8% to 3.4%/-1.6%) during sodiation/desodiation processes. The dr-ReS2-x/NCBC anode was also assembled coupling with Na3V2(PO4)3 cathode as a sodium-ion full cell for practical applications. This work is expected to offer an in-depth understanding between dual-defect engineering in TMDs-based anodes and as-enhanced sodium-storage performance.