Sn Nanoparticles Research Articles

Towards stable and high‐capacity anode materials for sodium‐ion batteries by embedding of Sb/Sn nanoparticles into electrospun mesoporous carbon fibers

AbstractAntimony and tin are promising anode materials for sodium‐ion batteries due to their high theoretical sodium storage capacities. However, significant volume change during cycling limits their long‐term stability and rate performance. Composite engineering can minimize this problem. A versatile method for the synthesis of Sb nanoparticles inside the mesopores of carbon fibers prepared through electrospinning and subsequent carbothermal reduction is presented in this work. The mesopore architecture can host up to 61 wt% of Sb nanoparticles and buffer the volume changes during cycling. Smaller pores in the carbon provide the pathways for reversible insertion/extraction of sodium. This binder‐free material provides high rate capability and a long‐term cycling performance when used as an anode in half‐cells. When cycled at 0.5 A g−1, the composite shows an initial capacity of 520 mA h g−1 with 507 mA h g−1 remaining after 500 cycles. Even at a high current density of 20 A g−1, a capacity of 197 mA h g−1 is still achieved. Sn nanoparticles can be embedded in the mesopores of the carbon fibers by a similar method. These Sn‐based anodes also show remarkable electrochemical performance, indicating that this approach represents a generally applicable strategy for synthesizing advanced battery anodes.

Synthesis and Characterization of Sn/Ag Nanoparticle Composite as Electro-Catalyst for Fuel Cell

In this research, Sn/Ag nanoparticle composite was produced by using chemical reduction method with the aids of sodium borohydride as reducing agent and sodium succinate as protective agent. The XRD, EDX, and TEM analyses showed that the Sn/Ag nanoparticle composite was formed with an average particle size of 4.37 + 0.44 nm. For the application, LSV analysis was done on Sn nanoparticle and Sn/Ag nanoparticle composite samples, and the analysis showed current produced from Sn/Ag nanoparticle composite (4.10 × 10-6 A) is higher than Sn nanoparticle (3.47 × 10-6 A) at the potential of -0.83V.

Sn/FeSn2/FeO@N-doped carbon yolk-shell nanocubes with multi-phase nanocores for highly stable anode materials in lithium-ion battery

A two-step approach using co-precipitation and thermal reduction treatment strategy is adopted to synthesize Sn/FeSn2/[email protected] carbon yolk-shell nanocubes with multi-phase nanocores for highly stable anode materials in lithium-ion battery. In the novel yolk-shell nanostructure, the multi-phase nanocores consist of Sn, FeSn2 and FeO nanoparticles while the shell is made of amorphous nitrogen-doped carbon. With the synergy of multi-phase nanocores, the confining effect of the carbon shell and the in-depth nanocrystallization of Sn/FeSn2/FeO nanocores in the yolk-shell nanostructures, Sn/FeSn2/[email protected] nanocomposites exhibit high capacity of 601 mAh g−1 at 0.1 Ag−1 after the 300th cycle and capacity of 484 mAh g−1 at 0.5 Ag−1 after the 600th cycle. Our work suggests that high-performance battery materials can be produced by rational structure engineering of multi-phase nanocomposites.

A flexible electromagnetic wave-electricity harvester

Developing an ultimate electromagnetic (EM)-absorbing material that can not only dissipate EM energy but also convert the generated heat into electricity is highly desired but remains a significant challenge. Here, we report a hybrid Sn@C composite with a biological cell-like splitting ability to address this challenge. The composite consisting of Sn nanoparticles embedded within porous carbon would split under a cycled annealing treatment, leading to more dispersed nanoparticles with an ultrasmall size. Benefiting from an electron-transmitting but a phonon-blocking structure created by the splitting behavior, an EM wave-electricity device constructed by the optimum Sn@C composite could achieve an efficiency of EM to heat at widely used frequency region and a maximum thermoelectric figure of merit of 0.62 at 473 K, as well as a constant output voltage and power under the condition of microwave radiation. This work provides a promising solution for solving EM interference with self-powered EM devices.

Ionic liquid assisted electrospinning synthesis for ultra-uniform Sn@ mesoporous carbon nanofibers as a flexible self-standing anode for lithium ion batteries

The long-cycle-life and high-capacity Sn@ Mesoporous Carbon Nanofibers (Sn@MCNFs-IL) self-standing anode was prepared by ionic liquid assisted electrospinning and pyrolysis strategy. Ionic liquid (AminCl) modifies the interface between the active particles and the electrospinning solutions, affecting electrospinning and pyrolysis process. The structure of ultra-uniform Sn encapsulated in porous carbon nanofibers resolves severe aggregation of Sn nanoparticles in carbon nanofibers, thus releasing stress form volume expansion of Sn and increasing storage lithium ions surface area of the Sn. The ultra-uniform Sn@MCNF-IL anode exhibited high capacity of 750 mA h g−1 at 0.5 A g−1 (comparing with Sn@CNF anode, improved 22%) with excellent Coulombic efficiency (89% at 1st cycle) and rate performance (300, 200 mA h g−1 at 4.0 and 10.0 A g−1). Remarkably, the cycling capability of the Sn@MCNF-IL anode (504 mA h g−1, 800 cycles at 0.5 A g−1) is superior to the cycling performance of Sn@CNF. The ionic liquid assisted strategy hopefully provides an advanced strategy in construction of excellent self-standing anode and the Sn@MCNFs-IL shows great promise as a candidate anode for superior performance flexible lithium-ion batteries.

Transformation of SnS Nanocompisites to Sn and S Nanoparticles during Lithiation

SnS nanomaterials have a high initial capacity of 1000 mAh g−1; however, this cannot be retained throughout electrochemical cycling. The present study provides insight into this capacity decay by examining the effect that Li intercalation has on SnS “nanoflowers” attached on carbon substrates’ such as artificial graphite. Scanning and transmission electron microscopy reveal that lithiation of such materials disrupts their initial morphology and produces free-standing Sn and SnS nanoparticles that dissolve in the electrolyte and disperse uniformly over the entire electrode surface. As a result, the SnS is rendered inactive after initial cycling and contributes to the formation of the solid electrolyte interface layer, resulting in continuous capacity decay during long term cycling. This is the first study that illustrates the morphological effects that the conversion mechanism has on SnS anodes. In order to fully utilize SnS materials, it is necessary to isolate them from the electrolyte by fully encapsulating them in a matrix.

MOF-derived porous carbon nanofibers wrapping Sn nanoparticles as flexible anodes for lithium/sodium ion batteries

Facile synthesis of flexible electrodes with high reversible capacity plays a key role in meeting the ever-increasing demand for flexible batteries. Herein, we incorporated Sn-based metal-organic framework (Sn-MOF) templates into crosslinked one-dimensional carbon nanofibers (CNFs) using an electrospinning strategy and obtained a hierarchical porous film (Sn@C@CNF) after a carbothermal reduction reaction. Merits of this modification strategy and its mechanism in improving the electrochemical performance of Sn nanoparticles (NPs) were revealed. Electrospun CNFs substrate ensured a highly conductive skeleton and excellent mechanical toughness, making Sn@C@CNF a self-supported binder-free electrode. Serving as a self-sacrificing template, Sn-MOF provided Sn NPs and derived into porous structures on CNFs after pyrolysis. The hierarchical porous structure of the carbon substrate was beneficial to enhancing the Li+/Na+ storage of the active materials, and the carbon wrappings derived from polyacrylonitrile (PAN) nanofibers and the MOF skeleton could jointly accommodate the violent volume variation during cycling, enabling Sn@C@CNF to have excellent cycle stability. The Sn@C@CNF anode exhibited a stable discharge specific capacity of 610.8 mAh g−1 under 200 mA g−1 for 180 cycles in lithium ion batteries (LIBs) and 360.5 mAh g−1 under 100 mA g−1 after 100 cycles in sodium ion batteries (SIBs). As a flexible electrode, Sn@C@CNF demonstrated a stable electromechanical response to repeated ‘bending-releasing’ cycles and excellent electrochemical performance when assembled in a soft-pack half-LIB. This strategy provided promising candidates of active materials and fabrication methods for advanced flexible batteries.

High-mass-loading Sn-based anode boosted by pseudocapacitance for long-life sodium-ion batteries

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries in large-scale energy storage due to the abundant sodium resources and low cost. However, the practical applications are still hindered by several factors such as limited cycling life and low mass loading of the electrode. Herein, a uniform free-standing Sn-based (Sn@CFC) electrode was synthesized via a facile electrospinning method. The cross-link nitrogen-doped carbon fiber and ultrasmall metallic Sn nanoparticles together provide fast ions and electrons pathway, enabling a dominant pseudocapacitance contribution of 87.1% at a scan rate of 0.5 mV s−1. The Sn@CFC electrode hence exhibits a high reversible area capacity of 1.68 mAh cm−2 at 50 mA g−1 and long cycle life of 1000 cycles at 200 mA g−1 with more than 80% capacity retention. Moreover, the facile manufacturing technique yields the Sn@CFC electrode with an extremely high mass loading of 5.5 mg cm−2 with very little sacrifice of electrochemical performances. This study provides a promising route to scalably fabricate electrodes with high area capacity and high energy density for advanced SIBs.

Well-dispersed tin nanoparticles encapsulated in amorphous carbon tubes as high-performance anode for lithium ion batteries

Tin/carbon (Sn/C) nanocomposite is considered as a promising anode material for high-performance Li-ion batteries (LIBs). However, since the carbon matrix is always derived from high-temperature carbonization of polymers and Sn has a low melting point (232 °C), the Sn nanoparticles in the Sn/C tend to be heavily aggregated during the carbonization process. It is thus challenging to synthesize well-dispersed Sn nanoparticles in a carbon matrix. Here, we report a facile templating method to encapsulate uniform well-dispersed Sn nanoparticles in amorphous carbon tube (Sn@aCT). The electrode fabricated with the hierarchical Sn@aCT exhibits excellent cycle performance. A stable specific capacity of 870 mAh g−1 after 350 cycles and a Li-ion diffusion coefficient as high as are obtained. Meanwhile, the intermediate structure of SnO2@aCT and a carbon-coated Sn yolk-shell nanostructure (Sn@C-YS) are investigated for comparison. The results further manifest the advantage of the architecture of the Sn@aCT. Our strategy provides a feasible way to optimize Sn/C nanocomposite as a high-performance anode material for LIBs.

Organic molecule confinement reaction for preparation of the Sn nanoparticles@graphene anode materials in Lithium-ion battery

Sn@Graphene composites as anode materials in Lithium-ion batteries have attracted intensive interest due to the inherent high capacity. On the other side, the high atomic ratio (Li4.4Sn) induces the pulverization of the electrode with cycling. Thus, suppressing pulverization by designing the structure of the materials is an essential key for improving cyclability. Applying the nanotechnologies such as electrospinning, soft/hard nano template strategy, surface modification, multi-step chemical vapor deposition (CVD), and so on has demonstrated the huge advantage on this aspect. These strategies are generally used for homogeneous dispersing Sn nanomaterials in graphene matrix or constructing the voids in the inner of the materials to obtain the mechanical buffer effect. Unfortunately, these processes induce huge energy consumption and complicated operation.To solve the issue, new nanotechnology for the composites by the bottom-up strategy (Organic Molecule Confinement Reaction (OMCR)) was shown in this report. A 3D organic nanoframes was synthesized as a graphene precursor by low energy nano emulsification and photopolymerization. SnO2 nanoparticles@3D organic nanoframes as the composites precursor were in-situ formed in the hydrothermal reaction. After the redox process by the calcination, the Sn nanoparticles with nanovoids (~100 nm, uniform size) were homogeneously dispersed in a Two-Dimensional Laminar Matrix of graphene nanosheets (2DLMG) by the in-situ patterning and confinement effect from the 3D organic nanoframes. The pulverization and crack of the composites were effectively suppressed, which was proved by the electrochemical testing. The Sn nanoparticles@2DLMG not delivered just the high cyclability during 200 cycles, but also firstly achieved a high specific capacity (539 mAh g−1) at the low loading Sn (19.58 wt%).

Utilizing E-Waste for Construction of Magnetic and Core-Shell Z-Scheme Photocatalysts: An Effective Approach to E-Waste Recycling.

The increasingly large stream of e-waste is seriously threatening the environment; meanwhile, global energy shortage is on the rise. Based on the principles of energy regeneration and waste utilization, we introduced a win-win approach to utilize waste capacitors for construction of magnetic and core-shell Z-scheme Nb-Pb-codoped BaTiO3/Ni-Pd@graphite-like carbon nitride (g-C3N4) photocatalysts for H2 evolution. Using simple ball-milling, waste capacitors were transformed to Nb-Pb-codoped BaTiO3/Ni-Pd-Ag-Sn nanoparticles and g-C3N4 was coated on the nanoparticles, forming a core-shell structure. The Ni-Pd acted as the electron mediator in the Z-scheme, and Ag-Sn also facilitated the electron transfer. Moreover, Ni made the Z-scheme magnetically separable. The Z-scheme showed a remarkably enhanced photocatalytic H2 evolution rate, which was 22.2 times higher than that of g-C3N4. Such an enhanced photocatalytic performance was attributed to the special Z-scheme and core-shell structure, improving the light adsorption, increasing the Brunauer-Emmett-Teller (BET) surface area, facilitating the efficient separation of electron-hole pairs, and maintaining the strong redox ability of charge carriers. Furthermore, the photoluminescence analysis combined with density functional theory (DFT) calculations provided the basis for the Z-scheme mechanism. This study adequately utilized the composition of e-waste to construct a highly efficient and magnetically separable Z-scheme for H2 generation, which realizes energy regeneration, waste recycling, and environmental protection.

Contrasting the EXAFS obtained under air and H2 environments to reveal details of the surface structure of Pt-Sn nanoparticles.

Understanding the surface structure of bimetallic nanoparticles is crucial for heterogeneous catalysis. Although surface contraction has been established in monometallic systems, less is known for bimetallic systems, especially of nanoparticles. In this work, the bond length contraction on the surface of bimetallic nanoparticles is revealed by XAS in H2 at room temperature on dealloyed Pt-Sn nanoparticles, where most Sn atoms were oxidized and segregated to the surface when measured in air. The average Sn-Pt bond length is found to be ∼0.09 Å shorter than observed in the bulk. To ascertain the effect of the Sn location on the decrease of the average bond length, Pt-Sn samples with lower surface-to-bulk Sn ratios than the dealloyed Pt-Sn were studied. The structural information specifically from the surface was extracted from the averaged XAS results using an improved fitting model combining the data measured in H2 and in air. Two samples prepared so as to ensure the absence of Sn in the bulk were also studied in the same fashion. The bond length of surface Sn-Pt and the corresponding coordination number obtained in this study show a nearly linear correlation, the origin of which is discussed and attributed to the poor overlap between the Sn 5p orbitals and the available orbitals of the Pt surface atoms.

Extending the Polyol Reduction Process into the Second Dimension: Oxide Thin Film Reduction

The formation of extended metal thin films (<5 nm) or monolayers on oxide surfaces, for applications in (electro-)catalysis, has never been achieved due to the high interfacial energy of the metal/oxide interface that always results in a 3D growth of the deposited metal. To realize 2D growth, the outermost surface of the oxide must be reduced prior to metal deposition in the same system. Here, we demonstrate that the polyol method, typically used for metal nanoparticles synthesis, can be used for the reduction of oxide thin films. The reduction of the oxide layer upon heating in ethylene glycol was electrochemically monitored in situ by measuring the open circuit potential and confirmed by cyclic voltammetry and near ambient pressure X-ray photoelectron spectroscopy. The reduction of oxide thin films could be verified for nanoparticles of Sn, Ni and Sb-doped SnO2 in accordance with thermodynamic calculations. This method will enable the formation of metal thin films and monolayers on oxide substrates for applications in (electro-)catalysis.

Ammonium ion-promoted electrochemical production of synthetic gas from water and carbon dioxide on a fluorine-doped tin oxide electrode.

In situ generated Sn nanoparticles on fluorine-doped tin oxide act as an electrocatalyst for the CO2 reduction reaction to efficiently and stably produce synthetic gas from water and carbon dioxide with the reaction rate drastically enhanced by the addition of ammonium ions.

Sn nanoparticles deposited onto a gas diffusion layer via impregnation-electroreduction for enhanced CO2 electroreduction to formate

Sn-based gas diffusion electrodes (GDEs) are promising for electroreduction of CO2 to formate (ERCF) as they can alleviate CO2 mass transfer limitations. However, current electrodes suffer from large catalyst size or poor electron and/or ion connections. This limits ERCF performance. Here, we report a Sn-based GDE (IE-Sn) for ERCF fabricated via deposition of Sn nanoparticles onto a gas diffusion layer by using an impregnation-electroreduction method. The characterization results showed that the IE-Sn has small Sn catalyst size (16 nm) and excellent electronic and ionic transfer properties. Moreover, the faradaic efficiency (87.12 ± 4.28%) and partial current density for formate (62.79 ± 5.33 mA cm−2) obtained from the IE-Sn is 2.45-fold and 4.86-fold, respectively, of those of the traditional electrode. This ERCF performance is one of the best among recently reported Sn-based GDEs under similar conditions. Further analyses reveal that the enhanced ERCF performance of the IE-Sn is linked to the large electroactive surface area, enhanced adsorption capacity and chemisorption ability of CO2, better stabilization of CO2.– intermediate, and excellent ion/electron transfer. This study offers design rules to fabricate high-performance electrode materials for ERCF.

Enhanced efficiency for carbon dioxide electroreduction to formate by electrodeposition Sn on Cu nanowires

Electroreduction of CO2 to formate is one of the most promising methods for CO2 utilization and conversion. However, low conversion efficiency and poor stability of electrodes limit its practical application. In this study, Sn are electrodeposited on copper nanowires (Sn/Nano-Cu) to serve as the electrode for the electroreduction of CO2 to formate. Results show that Sn nanoparticles are uniformly distributed on copper nanowires. When the potential of −1.2 V (vs. RHE) is applied, the prepared Sn/Nano-Cu electrode exhibits the maximum Faradaic efficiency as high as 86.8 % with a current density of 38.0 mA cm−2. The formate production rate reaches 575.1 ± 24 μmol h-1 cm−2, which is 1.9 and 2.9 times that of the Sn/Cu and Sn foil electrode, respectively. The excellent CO2 electrochemical reduction performance may be attributed to the large electroactive surface area and low charge transfer resistance. Moreover, the Sn/Nano-Cu electrode can maintain high Faraday efficiency during 25 h test. The superior electrocatalytic performance as well as good stability for CO2 electroreduction is achieved by the Sn/Nano-Cu electrode.

In situ one–pot synthesis of Sn/lignite–based porous carbon composite for enhanced lithium storage

To expand the variety of Sn/C composites, lignite–based porous carbon was initially prepared with Baoqing lignite as the raw material and K2CO3 as the extractant and activator. A novel Sn/lignite–based porous carbon composite was subsequently fabricated via an in situ one–pot synthesis method. In the nanocomposite, Sn nanoparticles are uniformly distributed on lignite–based porous carbon, improving the lithium–ion storage performance of the as–prepared material. Compared with pure Sn and bare lignite–based porous carbon, Sn/lignite–based porous carbon displayed a superior electrochemical performance. The composite material exhibits a high reversible capacity of 941 mAh g−1 after 200 cycles at 100 mA g−1. Even after 800 charge/discharge cycles at a high current density of 1000 mA g−1, the nanocomposite retains a reversible capacity of 573 mAh g−1. The enhanced lithium–ion storage performance can be attributed to the combined effect of Sn and lignite–based porous carbon.

A Glass‐Ceramic with Accelerated Surface Reconstruction toward the Efficient Oxygen Evolution Reaction

AbstractThe effective non‐precious metal catalysts toward the oxygen evolution reaction (OER) are highly desirable for electrochemical water splitting. Herein, we prepare a novel glass‐ceramic (Ni1.5Sn@triMPO4) by embedding crystalline Ni1.5Sn nanoparticles into amorphous trimetallic phosphate (triMPO4) matrix. This unique crystalline‐amorphous nanostructure synergistically accelerates the surface reconstruction to active Ni(Fe)OOH, due to the low vacancy formation energy of Sn in glass‐ceramic and high adsorption energy of PO43− at the VO sites. Compared to the control samples, this dual‐phase glass‐ceramic exhibits a remarkably lowered overpotential and boosted OER kinetics after surface reconstruction, rivaling most of state‐of‐the‐art electrocatalysts. The residual PO43− and intrinsic VO sites induce redistribution of electron states, thus optimizing the adsorption of OH* and OOH* intermediates on metal oxyhydroxides and promoting the OER activity.

A Glass-Ceramic with Accelerated Surface Reconstruction toward the Efficient Oxygen Evolution Reaction.

The effective non-precious metal catalysts toward the oxygen evolution reaction (OER) are highly desirable for electrochemical water splitting. Herein, we prepare a novel glass-ceramic (Ni1.5 Sn@triMPO4 ) by embedding crystalline Ni1.5 Sn nanoparticles into amorphous trimetallic phosphate (triMPO4 ) matrix. This unique crystalline-amorphous nanostructure synergistically accelerates the surface reconstruction to active Ni(Fe)OOH, due to the low vacancy formation energy of Sn in glass-ceramic and high adsorption energy of PO4 3- at the VO sites. Compared to the control samples, this dual-phase glass-ceramic exhibits a remarkably lowered overpotential and boosted OER kinetics after surface reconstruction, rivaling most of state-of-the-art electrocatalysts. The residual PO4 3- and intrinsic VO sites induce redistribution of electron states, thus optimizing the adsorption of OH* and OOH* intermediates on metal oxyhydroxides and promoting the OER activity.

A detailed study on the growth of silicon nanowires by hot wire chemical vapor process: concept of critical size of Sn catalyst

The size of silicon nanowires (SiNWs) plays an important role for their application in nanoelectronic and nanophotonic systems. Therefore, it is of great interest to study the synthesis conditions of SiNWs in order to grow SiNWs with well-controlled manner to be integrated into a device. This paper includes a systematic study of the dependence of diameter and length of the SiNWs on the growth conditions. SiNWs were synthesized via vapor–liquid–solid (VLS) mechanism using a catalyst film of Sn nanoparticles on stainless steel (SS) substrate. The morphology and microstructure of SiNWs synthesized at different parameters were investigated with scanning electron microscopy and Raman spectroscopy. In this study, we have observed that there exists a minimum size of the catalyst to initiate the growth of SiNWs for a given set of process parameters. Furthermore, this work also addresses the difficulties associated with the growth of long SiNWs. Effect of filament temperature on the morphology of SiNWs has also been studied. It is observed that their dimensions and geometrical orientation are greatly influenced by the filament temperature. At filament temperatures between 1400 and 1600 °C, short SiNWs with random distributions are observed. Long and vertical SiNWs are found if the filament temperature was raised to 1800–1950 °C.