Reversible Iodine Intercalation into Tungsten Ditelluride

Abstract

The new compound WTe2I was prepared by a reaction of WTe2 with iodine in a fused silica vessel at temperatures between 40 and 200 °C. Iodine atoms are intercalated into the van der Waals gap between tungsten ditelluride layers. As a result, the WTe2 layer separation and therefore the c-axis length is significantly increased, and the orthorhombic space group is preserved. Iodine atoms form planar layers between each tungsten ditelluride layer. Due to oxidation by iodine the semi-metallic nature of WTe2 is changed, as shown by comparative band structure calculations for WTe2 and WTe2I based on density functional theory. The calculated phonon band structure of WTe2I suggests a charge density wave instability at low temperature. File list (2)download file view on ChemRxiv WTe2I-CPR-V2.pdf (2.31 MiB) download file view on ChemRxiv WTe2I-SI.pdf (832.36 KiB)

Quasi-2D Bi0.775Ln0.225O1.5 (Ln = La, Pr, Nd, Sm, Eu): reversible iodine intercalation and their evaluation as the anode in the lithium-ion battery system

“…An evaluative comparison of the anode performance of our samples with other 2D materials is given in Table S3 (ESI †). 37,47,[55][56][57] Although the electrochemical characteristics of the present materials are not outstanding, sustaining capacity at a higher current rate (50 mA g −1 ) for longer cycles (500) is quite promising. Designing hybrid nanostructures and/or composites with iodine-intercalated layered bismuth oxide systems is further planned to improve the anode characteristics (rate capability and cycling stability).…”

“…The rapid capacity decay on increasing the current density may be caused by aggravated polarisation arising from the weakened ionic diffusion through the enlarged area and electric conductivity of electrodes. 47,[55][56][57] The rate performance of prepared cells is shown in Fig. 10(a).…”

“…It limits the cycle life and performance of lithium-ion batteries. 37,47,[55][56][57] The discharged and charged BPO-I sample (after 500 cycles) was analyzed by powder X-ray diffraction to verify the structural stability. From the PXRD results, the layer structure appears to be intact, with the appearance of diffraction peaks related to (0 0 l) hkl matching well with the pattern of the BPO-I sample before its evaluation in charge-discharge cycles (Fig.…”