Facile synthesis and electrochemical sodium storage of CoS2 micro/nano-structures
cobalt disulfide, micro/nano-structures, sodium storage mechanism, cycling stability
We report the synthesis and electrochemical sodium storage of cobalt disulfide (CoS2) with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles (P-CoS2) via a facile solvothermal route or nanooctahedrons constructed solid (O-CoS2) and hollow microstructures (H-CoS2) fabricated by hydrothermal methods. Among three morphologies, H-CoS2 exhibits the largest discharge capacities and best rate performance as anode of sodium-ion batteries (SIBs). Furthermore, H-CoS2 delivers a capacity of 690 mA·h·g−1 at 1 A·g−1 after 100 cycles in a potential range of 0.1–3.0 V, and ~240 mA·h·g−1 over 800 cycles in the potential window of 1.0–3.0 V. This cycling difference mainly lies in the two discharge plateaus observed in 0.1–3.0 V and one discharge plateau in 1.0–3.0 V. To interpret the reactions, X-ray diffraction (XRD) and transmission electron microscopy (TEM) are applied. The results show that at the first plateau around 1.4 V, the insertion reaction (CoS2 + xNa+ + xe− → NaxCoS2) occurs; while at the second plateau around 0.6 V, the conversion reaction (NaxCoS2 + (4 − x) Na+ + (4 − x)e− → Co + 2Na2S) takes place. This provides insights for electrochemical sodium storage of CoS2 as the anode of SIBs.
Tsinghua University Press
Xue Liu,Kai Zhang,Kaixiang Lei,Fujun Li,Zhanliang Tao,Jun Chen, Facile synthesis and electrochemical sodium storage of CoS2 micro/nano-structures. NanoRes.2016, 9(1): 198–206