Sn nanoparticles embedded into porous hydrogel-derived pyrolytic carbon as composite anode materials for lithium-ion batteries

The composite powders,Sn nanoparticles embedded into the porous hydrogel-derived carbon(Sn@PHDC),were successfully prepared by polymerization and calcination processes,and the characterization results confirmed that Sn nanoparticles were homogeneously dispersed in the porous hydrogel-derived pyrolytic carbon.The coin cell assembled with the Sn@PHDC-50 composite electrode presented good cyclic stability and rate performance when the weight ratio of Sn nanoparticles to hydrogel-derived pyrolytic carbon was maintained at 1:1.Moreover,the Sn@PHDC-50 electrode manifested a lower charge transfer resistance of 58.57 Ω and a higher lithium ions diffusion coefficient of 1.117×10^(-14) cm^(2)·s^(-1) than pure Sn and other Sn@PHDC electrodes.Those improvements can be partly ascribed to the fact that the hydrogelderived pyrolytic c arbon matrix can release the volume strain and enhance the electronic conductivity of the composite electrode,and partly to the fact that the porous hydrogelderived pyrolytic carbon matrix can suppress agglomerations of Sn nanoparticles and shorten Li^(+) diffusion paths.This work may provide a new appro ach for the improvement of Sn-based anode materials for lithium-ion batteries.

Organic-inorganic hybrid hole transport layers with SnS doping boost the performance of perovskite solar cells

Perovskite solar cells(PSCs) have demonstrated excellent photovoltaic performance which currently rival the long-standing silicon solar cells’ efficiency. However, the relatively poor device operational stability of PSCs still limits their future commercialization. Binary sulfide is a category of materials with promising optoelectrical properties, which shows the potential to improve both the efficiency and stability of PSCs.Here we demonstrate that the inorganic tin monosulfide(Sn S) can be an efficient dopant in 2,2’,7,7’-tet rakis(N,N-di-p-methoxy-phenylamine)-9,9’-spirobifluorene(spiro-OMe TAD) to form a composite hole transport layer(HTL) for PSCs. Sn S nanoparticles(NPs) synthesized through a simple chemical precipitation method exhibit good crystallization and suitable band matching with the perovskites. The introduction of Sn S NPs in Spiro-OMTAD HTLs enhanced charge extraction, reduced trap state density, and shallowed trap state energy level of the devices based on the composite HTLs. Therefore, the resulting solar cells employing Sn S-doped spiro-OMe TAD HTLs delivered an improved stabilized power output efficiency of 21.75% as well as enhanced long-term stability and operational stability. Our results provide a simple method to modify the conventional spiro-OMe TAD and obtain PSCs with both high efficiency and good stability.

Microsized SnS/Few-Layer Graphene Composite with Interconnected Nanosized Building Blocks for Superior Volumetric Lithium and Sodium Storage

To develop anode materials with superior volumetric storage is crucial for practical application of lithium/sodium-ion batteries.Here,we have developed a micro/nanostructured Sn S/few-layer graphene(Sn S/FLG)composite by facile scalable plasma milling.Inside the hybrid,SnS nanoparticles are tightly supported by FLG,forming nanosized primary particles as building blocks and assembling to microsized secondary granules.With this unique micro/nanostructure,the Sn S/FLG composite possesses a high tap density of 1.98 g cm^(-3)and thus ensures a high volumetric storage.The combination of Sn S nanoparticles and FLG nanosheets can not only enhance the overall electrical conductivity and facilitate the ion diffusion greatly,but alleviate the large volume expansion of Sn S effectively and maintain the electrode integrity during cycling.Thus,the densely compacted Sn S/FLG composite exhibits superior volumetric lithium and sodium storage,including high volumetric capacities of 1926.5/1051.4 m Ah cm^(-3)at 0.2 A g^(-1),and high retained capacities of 1754.3/760.3 m Ah cm^(-3)after 500cycles at 1.0 A g^(-1).With superior volumetric storage performance and facile scalable synthesis,the Sn S/FLG composite can be a promising anode for practical batteries application.

Preparation and characterization of sphere-like Cu_2SnS_3 nanoparticles and their dropcasted thin films

Ternary sphere-like Cu2 SnS3（CTS）semiconductor and 2D hexagonal sheets were synthesized via a simple solvothermal method using PVP as the surface ligand at two temperatures of 180 and 220 X.The structural,morphological,and chemical compositions as well as optical properties of as-synthesized CTS particles were characterized using X-ray diffraction（XRD）,Raman spectroscopy,energy dispersive X-ray spectrometry（EDS）,field emission scanning electron microscopy（FESEM）,and UV-Vis spectroscopy.The size of sphere-like particles and the side length of hexagonal sheets were within the range of 120-140 nm and 500 nm-2 μm,respectively.FESEM,XRD,and EDS were analyzed to investigate the mechanism of the morphological evolution of CTS particles.CTS particles showed proliferation of Sn atomic ratio,which is strongly sensitive to reaction temperature and,highly affects the increase of band gap energy from 1.36 to 1.53 eV due to generation metal defects and formation SnS2-The optical analysis via the transmittance and reflectance reveals that the band-gap energy of dropcasted CTS thin films decreases after annealing due to grain growth and change of chemical compositions.Photo-responses of CTS nanocrystal thin films indicated a considerable increase in the conductivity of the films under light illumination.All these results showed the potential of these films for solar cell applications.

Construction of SnS-Mo-graphene nanosheets composite for highly reversible and stable lithium/sodium storage

Sn-based chalcogenides are considered as one of the most promising anode materials for lithium-ion batteries(LIBs)because of their high capacities through both conversion and alloying reactions.However,the realization of full capacities of Sn-based chalcogenides is mainly hindered by the large volume variation and inferior reversibility of conversion reaction during cycling.In present work,a new ternary Sn SMo-graphene nanosheets(Sn S-Mo-GNs)composite is fabricated by a simple and scalable plasma milling method,in which Sn S nanoparticles are tightly bonded with Mo and GNs.The Mo and GNs additives can effectively alleviate the large volume change of Sn S upon cycling,which leads to a stable electrochemical framework.Moreover,they can significantly suppress the Sn agglomeration in lithiated Sn S,which enables highly reversible conversion reaction during cycling.As anode for LIBs,the Sn S-Mo-GNs composite exhibits a high initial coulombic efficiency of 86.9%(almost complete reversibility of Sn S,~97.3%),high cyclic coulombic efficiency after initial three cycles(>99.5%),and long lifespan(up to 600 cycles).Moreover,it also demonstrates superior electrochemical performance for sodium storage.Thus,this work demonstrates a potential anode for batteries application and provides a viable strategy to obtain highly reversible and stable anodes for lithium/sodium storage.