Lightweight and High-Performance Microwave Absorber Based on 2D WS2-RGO Heterostructures

Two-dimensional(2D)nanomaterials are categorized as a new class of microwave absorption(MA)materials owing to their high specific surface area and peculiar electronic properties.In this study,2D WS2-reduced graphene oxide(WS2-rGO)heterostructure nanosheets were synthesized via a facile hydrothermal process;moreover,their dielectric and MA properties were reported for the first time.Remarkably,the maximum reflection loss(RL)of the sample-wax composites containing 40 wt% WS2-rGO was-41.5 dB at a thickness of 2.7 mm;furthermore,the bandwidth where RL<-10 dB can reach up to 13.62 GHz(4.38-18 GHz).Synergistic mechanisms derived from the interfacial dielectric coupling and multiple-interface scattering after hybridization of WS2 with rGO were discussed to explain the drastically enhanced microwave absorption performance.The results indicate these lightweight WS2-rGO nanosheets to be potential materials for practical electromagnetic wave-absorbing applications.

Intimately coupled WS_(2) nanosheets in hierarchical hollow carbon nanospheres as the high-performance anode material for lithium-ion storage

Lithium-ion hybrid capacitors(LIHCs)have drawn extensive attention in fleld of energy storage.However,the absence of appropriate electrode materials with rapid kinetics restricted the overall performance of the capacitors.Herein,hierarchical N,P-codoped hollow car-bon nanospheres coupling with WS_(2) nanosheets(N,P-codoped HCNS/WS_(2)NSs)were fabricated for boosting lithium storage materials.Specially,the WS_(2) nanosheets with several layers embedded in the N,P-codoped hollow carbon nanospheres could not only enhance the conduc-tivity of composites,but also provide abundant channels for the rapid transfer of ions.As a result,as-prepared N,P-codoped HCNS/WS_(2) NSs demonstrated superior rate performance and long-term cycling stability.The reversible discharge capacity of 725.2 mAh·g^(-1) could be preserved after 1000 cycles at a current density of 1.0 A·g^(-1).Fur-thermore,LIHCs devices were assembled by using N,P-codoped HCNS/WS_(2) NSs and activated carbon(AC)as the cathode and anode,which exhibited high energy density of 166.7 Wh·kg^(-1) and power density of 5312.4 W·kg^(-1).Last but not least,the capacity almost had no obvious deterioration after 6000 cycles at a high current density of 10.0 A·g^(-1).

PEGylated WS_2 nanosheets for X-ray computed tomography imaging and photothermal therapy

WS2 nanosheets were prepared by the solvent-thermal method in the presence of n-butyl lithium, then the exfoliation under the condition of ultrasound. The formed WS2 nanosheets were conjugated with thiol-modified polyethylene glycol （PEG-SH） to improve the biocompatibility. The nanosheets （WS2- PEG） were able to inhibit the growth of a model HeLa cancer cell line in vitro due to the high photothermal conversion efficiency of ~35% irradiated by an 808 nm laser （1 W/cm^2）. As a proof of concept, WS2-PEG nanosheets with the better X-ray attenuation property than the clinical computed tomography （CT） contrast agent （lohexol） could be performed for CT imaging of the lymph vessel.