Ultrafine SnO2 Nanoparticles Research Articles

Fabrication of uniform Si-incorporated SnO2 nanoparticles on graphene sheets as advanced anode for Li-ion batteries

SnO2-based anodes with high capacity are appealing for Li-ion batteries (LIBs). However, the large volume change and inferior cycling stability limit their practical application. To mitigate these problems, a novel nanocomposite of silicon-incorporated SnO2 with graphene sheets (STOG) has been successfully fabricated as anode material for LIBs. Through a simple hydrolysis process, ultrafine Si-incorporated SnO2 (STO) nanoparticles are uniformly loaded on the graphene sheets. Further it is found that Si incorporation brings about the SiOSn bonding in the SnO2 matrix and strengthens the SnOC bonding between STO and graphene. These merits can enhance the structural stability and electron/ion transport of STOG nanocomposite, facilitating the reversible conversion of Sn–SnO2. As a result, this STOG material delivers a high discharge capacity of 1117.8 mAh g−1 and retains 92.5% of the second capacity after 100 cycles at 0.1 A g−1. Furthermore, an excellent rate capacity of 683.9 mAh g−1 can be obtained at a high current of 1 A g−1. This work provides an effective way to design high-performance SnO2-based anode material for LIBs.

Large-scale carbon framework microbelts anchoring ultrafine SnO2 nanoparticles with enhanced lithium storage properties

Varieties of nanostructured SnO2 have been widely investigated as promising anode material for next generation lithium-ion batteries (LIBs). However, traditional nanostructures suffer from re-agglomeration and excessive side reactions, which lead to low coulombic efficiency, poor rate performance and dramatic capacity decay. Here we develop an easy and robust strategy to fabricate carbon framework microbelts anchoring ultrafine SnO2 nanoparticles (U-SnO2 NPs@ CF-MBs), which takes advantage of the synergistic effect between high conductivity of large-size carbon framework and high activity of ultrafine SnO2 nanoparticles. The as-fabricated U-SnO2 NPs@C-BsF composite deliver high capacity of 925 mAh g−1 after 250 cycles at current density of 200 mA g−1, high rate capacity of 464 mAh g−1 at a high current density of 5000 mA g−1 and long cycle performance of 788 mAh g−1 after 1000 cycles at current density of 1500 mA g−1 in half cells. When applied in a full cell by coupling with a LiCoO2 cathode, the fabricated U-SnO2 NPs@ CF-MBs composite full cells keep a high capacity of 510 mAh g−1 after 80 cycles. Notably, the electrode exhibit two platforms located at 3.3 and 2.6 V, which indicate that the conversion between SnO2 and Sn is also highly reversible in full cells. The excellent lithium storage of large-scale U-SnO2 NPs@ CF-MBs ensures its great promise for commercial utilization in the future LIBs.

Microwave-assisted synthesis of SnO2/mesoporous carbon core-satellite microspheres as anode material for high-rate lithium ion batteries

The highly ordered microspheres containing ultrafine SnO2 nanoparticles and mesoporous carbon is fabricated using microwave-assisted hydrothermal method for high-rate and durable Li-ion battery application. The uniformly carbon nanosphere with an average diameter of around 90 nm exhibits large specific surface area and good mechanical stability to minimize the volume expansion of SnO2 during intercalation-deintercalation. The homogeneous coverage with 3–6 nm SnO2 nanoparticle provides sufficient active sites to facilitate the rapid lithiation-delithiation process through the fast ion transfer rates. Remarkably, SnO2/OMCS at Sn/C ratio of 35% exhibits an excellent initial capacity of 1770 mAh g−1 at a current density of 35 mA g−1 and can maintain at a stable capacity of 400 mAh g−1 under an ultra-high current density of 3500 mA g−1 after 400 cycles. The intimate contact of SnO2 with ordered mesoporous carbon sphere shortens the electrons transport paths, resulting in the enhancement of stable lithium storage capacity at a high current density. Results obtained in this study clearly demonstrate that SnO2/OMCS nanocomposite is a promising material for lithium-ion battery and can provide an alternative to fabricate novel mesoporous carbon sphere-based nanocomposites for long cycle life and high-rate energy storage application.

Revisiting the conversion reaction in ultrafine SnO2 nanoparticles for exceptionally high-capacity Li-ion battery anodes: The synergetic effect of graphene and copper

Generally, in SnO2-based anode materials, the reversible alloying/dealloying reaction is the main Li-ion storage mechanism. Interestingly, these materials can show an exceptionally high capacity that is beyond the theoretical value (i.e., 783 mA h g−1 based on Sn + 4.4Li+ + 4.4e− ⇌ Li4.4Sn reaction), owing to the reversibility of the reaction between Sn and Li2O to form SnOx (x = 1, 2), so-called conversion reaction. Herein, we prepare Cu-reduced graphene oxide (rGO)-SnO2 nanocomposites as a model system in order to demonstrate an effective strategy to improve the reversibility of the conversion reaction in SnO2. The incorporation of rGO can prevent the aggregation of SnO2 nanoparticles. Furthermore, the Cu-rGO-SnO2 nanocomposite exhibits the most improved conversion reaction reversibility, resulting in improved cycling performance and high capacity. Ex-situ transmission electron microscopy analysis confirms the high reversibility of the conversion as well as the alloying/dealloying reactions. Also, Cu nanoparticles promote the decomposition of amorphous Li2O, leading to enhancement of the conversion reaction between Sn and Li2O. Therefore, these results demonstrate a strategy for significantly improving the electrochemical performances of SnO2-based anodes for Li-ion batteries.

Organometallic Precursor-Derived SnO2/Sn-Reduced Graphene Oxide Sandwiched Nanocomposite Anode with Superior Lithium Storage Capacity

Benefiting from the reversible conversion reaction upon delithiation, nanosized SnO2, with its theoretical capacity of 1494 mA h g-1, has gained special attention as a promising anode material. Here, we report a self-assembled SnO2/Sn-reduced graphene oxide (rGO) sandwich nanocomposite developed by organometallic precursor coating and in situ transformation. Ultrafine SnO2 nanoparticles with an average diameter of 5 nm are sandwiched within the rGO/carbonaceous network, which not only greatly alleviates the volume changes upon lithiation and aggregation of SnO2 nanoparticles but also facilitates the charge transfer and reaction kinetics of SnO2 upon lithiation/delithiation. As a result, the SnO2/Sn-rGO nanocomposite exhibited a superior lithium storage capacity with a reversible capacity of 1307 mA h g-1 at a current density of 80 mA g-1 in the potential window of 0.01-2.5 V versus Li+/Li and showed a reversible capacity of 767 mA h g-1 over 200 cycles at a current density of 400 mA g-1. When cycling at a higher current density of 1600 mA g-1, the SnO2/Sn-rGO nanocomposite showed a highly stable capacity of 449 mA g-1 without obvious decay after 400 cycles.

Template synthesis of graphitic hollow carbon nanoballs as supports for SnOxnanoparticles towards enhanced lithium storage performance

To address the volume change-induced pulverization problem of tin-based anodes, a concept using hollow carbon nanoballs (HCNBs) as buffering supports is herein proposed. HCNBs with hollow interior, flexibility and graphitic crystallization are first prepared by a combined method of chemical vapor deposition (CVD) and template-synthesis using CH4 as the carbon source and CaCO3 as the conformal template. The ultrafine SnO2 nanoparticles are loaded onto the HCNBs (denoted as SnO2@HCNBs) via pyrolysis of tin(ii) 2-ethylhexanoate at 300 °C in air. On further annealing SnO2@HCNBs in Ar, SnO2 is partially reduced to SnOx by consuming a part of carbon of HCNBs as the reducing agent, and thus SnOx@HCNBs are obtained (note that SnOx represents a composite consisting of SnO2, SnO and Sn phases). When applied as anode materials for lithium ion batteries (LIBs), HCNBs deliver high reversible capacities of 841 mA h g-1 after 125 cycles at 200 mA g-1, and 726 mA h g-1 after 400 cycles even at 1000 mA g-1, while SnO2@HCNBs and SnOx@HCNBs exhibit discharge capacities of 1042 and 1299 mA h g-1 after 400 cycles at 200 mA g-1, respectively. Notably, all of them display gradually increased capacity with retention over 100% even after long-term cycling, which is attributed to the novel robust characteristic of the HCNBs as revealed by the ex situ TEM analysis. The flexible hollow HCNBs with high graphitic crystallization not only efficiently tolerate the volume changes of the Li-Sn alloying-dealloying but also facilitate the electrolyte/charge transfer owing to the hollow structure and high conductivity of the HCNBs.

Stepwise chelation-etching synthesis of carbon-confined ultrafine SnO2 nanoparticles for stable sodium storage.

A stepwise chelation-etching approach to synthesize carbon-confined ultrafine SnO2 nanoparticles was developed via conformal coating with polydopamine and chelation-etching with ethylenediaminetetraacetic acid (EDTA). EDTA plays a crucial role in the ordered removal of cobalt and tin. The obtained composite exhibits superior sodium storage performance.

Anchoring ultrafine Pd nanoparticles and SnO2 nanoparticles on reduced graphene oxide for high-performance room temperature NO2 sensing

In this paper, we demonstrate room-temperature NO2 gas sensors using Pd nanoparticles (NPs) and SnO2 NPs decorated reduced graphene oxide (Pd-SnO2-RGO) hybrids as sensing materials. It is found that ultrafine Pd NPs and SnO2 NPs with particle sizes of 3–5 nm are attached to RGO nanosheets. Compared to SnO2-RGO hybrids, the sensor based on Pd-SnO2-RGO hybrids exhibited higher sensitivity at room temperature, where the response to 1 ppm NO2 was 3.92 with the response time and recovery time being 13 s and 105 s. Moreover, such sensor exhibited excellent selectivity, and low detection limit (50 ppb). In addition to high transport capability of RGO as well as excellent NO2 adsorption ability derived from ultrafine SnO2 NPs and Pd NPs, the superior sensing performances of the hybrids were attributed to the synergetic effect of Pd NPs, SnO2 NPs and RGO. Particularly, the excellent sensing performances were related to high conductivity and catalytic activity of Pd NPs. Finally, the sensing mechanism for NO2 sensing and the reason for enhanced sensing performances by introduction of Pd NPs are also discussed.

Multifunctional SnO2/3D Graphene Composites for Lithium-Ion and Sodium-Ion Batteries

Although both Li-ion batteries (LIBs) and Na-ion batteries (NIBs) were investigated in the similar era (1980’s), LIBs are a current technology of choice for portable electronics and electric vehicle applications due to NIBs’ lower gravimetric/volumetric energy density. Recently, NIBs have gained another momentum for grid-scale energy storage systems (ESS) where the weight and volume limitations are relatively low. The most important requirements of EES would be the cost, reliability and long service life, while the high-energy density would be still viewed as an advantage. While looking slightly similar, Li and Na metals (and their cations) have distinct physical and chemical properties. It would be interesting to develop the multifunctional materials which can be used as effective electrode materials for both batteries. SnO2 is an attractive material due to high theoretical capacity (for both LIBs and NIBs), low cost, abundance and ease of synthesis. But there are many drawbacks that need to be overcome for SnO2 to be applied to actual batteries. Various technical issues include the large volume expansion during discharge/charge process in batteries, the formation of unstable solid electrolyte interface (SEI), and the aggregation of Sn particles during battery operation, all of which can lead to the rapid capacity fading of batteries. In this work, ultra-fine SnO2 nanoparticles dispersed within unique 3D-graphene structure (SnO2/3D GS) were synthesized by easy and simple hydrothermal process. These 3D-graphene structure could accommodate large volume change, prevent aggregation of Sn, and provide much facile electron transfer during battery operation. The SnO2/3D GS material exhibited outstanding electrochemical performances as anodes for both LIBs and NIBs. The structure-property-performance relation was investigated by various methods including SEM, TEM, EIS, CV, and XRD. The focus was on comparative studies of the internal resistance and diffusivity of Li-ions and Na-ions in SnO2/3D GS composites. Furthermore, the direct conversion from SnO2 to amorphous Sn during discharge/charge of 1st cycle in LIBs and NIBs was monitored by in-situ XRD. Figure 1

Micro-CaCO3 conformal template synthesis of hierarchical porous carbon bricks: As a host for SnO2 nanoparticles with superior lithium storage performance

We demonstrate a facile conformal template synthesis of hierarchical porous carbon bricks (HPCBs) via chemical vapor deposition (CVD) method using CH4 as carbon source and micro-CaCO3 bricks as a conformal template. The as-prepared HPCBs exhibit abundant interconnected meso/macro-sized cavities, large surface area, high graphitization degree and robust framework, which act as an efficient host to buffer the volume changes of Li-Sn alloying-dealloying when applied in lithium ion batteries. Ultrafine SnO2 nanoparticles are easily loaded onto the inner surfaces of the HPCBs via a facile pyrolysis of tin (II) 2-ethylhexanoate at 300 °C in air. The SnO2/HPCB electrode exhibits superior cycle stability and rate capability, delivering a high reversible capacity of 743.8 mA h/g after 180 cycles at 200 mA/g with capacity retention of 109.5%, which is much higher than that of HPCBs (308.6 mA h/g after 180 cycles at 200 mA/g with capacity retention of 87.7%). The hierarchical porous carbon materials synthesized using micro-CaCO3 as a conformal template can be a promising general host for various electrochemical energy storage applications.

Ultra-fine SnO2 nanoparticles doubly embedded in amorphous carbon and reduced graphene oxide (rGO) for superior lithium storage

SnO2 is a well-studied anode material for lithium ion batteries (LIBs). However, it undergoes severe capacity fading because of a large volume change (∼300%) during cycling. Composites of SnO2 with electro-conductive graphene would deliver improved capacity and rate performance. Nevertheless, achieving the theoretical capacity of SnO2 is still elusive, mainly because of disintegration of the active material from graphene and severe aggregation of SnO2, or Sn nanoparticles produced upon cycling. To surmount these limitations, in this work, nanocomposites containing ultra-fine sized SnO2 nanoparticles (UFSN) with reduced graphene oxide and amorphous carbon were synthesized in a single step at low temperature and environmentally benign way, in which ascorbic acid was employed as the carbon source and reducing agent. UFSN could decrease the lithium ion diffusion path length. As a result of effective buffering effect afforded by the mesoporous structure against volume change and improved lithium ion diffusivity, the ternary nanocomposite achieves ultra-high capacity of 1245mAhg−1 after 210 cycles at 100mAg−1 and excellent cycling stability. Since the proposed approach is facile, straightforward, and highly reproducible, it is anticipated that this system would be a potential alternative to the conventional graphite anode for LIBs.

Facile synthesis of ultrafine SnO2 nanoparticles on graphene nanosheets via thermal decomposition of tin-octoate as anode for lithium ion batteries

We demonstrate a facile synthesis of ultrafine SnO2 nanoparticles within graphene nanosheets (GNSs) via thermal decomposition of tin-octoate, in which tin-octoate is firstly blended with GNSs followed by annealing in air at a low temperature (350 °C) and a short time (1 h). As anode for lithium ion batteries, the SnO2/GNSs displays superior cycle and rate performance, delivering reversible capacities of 803 and 682 mA h/g at current densities of 200 and 500 mA/g after 120 cycles, respectively, much higher than that of pure SnO2 and GNSs counterparts (143 and 310 mA h/g at 500 mA/g after 120 cycles, respectively). The enhanced electrochemical performance is attributed to the ultrafine SnO2 nanoparticle size and introduction of GNSs. GNSs prevent the aggregation of the ultrafine SnO2 nanoparticles, which alleviate the stress and also provide more electrochemically active sites for lithium insertion and extraction. Moreover, GNSs with large specific surface area (~363 m2/g) act as a good electrical conductor which greatly improves the electrode conductivity and also an excellent buffer matrix to tolerate the severe volume changes originated from the Li-Sn alloying-dealloying. This work provides a straight-forward synthetic approach for the design of novel composite anode materials with superior electrochemical performance.

SnO2-Reduced Graphene Oxide Nanocomposites via Microwave Route as Anode for Sodium-Ion Battery

SnO2-reduced graphene oxide (SnO2-rGO) nanocomposites are successfully synthesized via a rapid microwave-assisted method (within 150 s). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show the ultrafine SnO2 nanoparticles (~3 nm) are uniformly anchored onto the rGO. The typical SnO2-rGO exhibits a high initial reversible capacity of 260 mAh g−1 at 50 mA g−1, which is higher than that (45 mAh g−1) of the bare SnO2 electrode. The SnO2-rGO electrode also shows high cycling stability (79.6% capacity retention after 100 cycles) and rate capability (150 mAh g−1 at 500 mA g−1). The improved electrochemical performance of the SnO2-rGO is ascribed to extremely tiny SnO2 nanoparticles well distributed on the surface of the rGO and the conductive frameworks provided by rGO, so as to alleviate the aggregation of SnO2 and buffer the volumetric change during charging and discharging.

Facile synthesis of ultrafine SnO2 nanoparticles embedded in carbon networks as a high-performance anode for lithium-ion batteries

Abstract SnO 2 @C nanocomposites are easily synthesized in a large scale by the hydrolysis of Sn 4+ ions in a polyacrylic acid (PAA) hydrogel system, followed by the decomposition of Sn(OH) 4 and carbonization of PAA by heat treatment in one-system. The SnO 2 @C nanocomposites contain uniform ultrafine SnO 2 nanoparticles (≈4.3 nm) homogenously embedded in a three-dimensional carbon matrix. This unique structure efficiently suppresses the particle pulverization and aggregation of SnO 2 , thus maintaining the electrode integrity during long-term lithiation/delithiation process. The discharge capacity of SnO 2 @C nanocomposites is maintained at ∼597.3 mAh g −1 after 220 cycles. This scalable approach has great potential in the applications of high-capacity anodes in Li-ion batteries.

SnO2 Nanoparticles Anchored on 2D V2O5 Nanosheets with Enhanced Lithium-Storage Performances

Developing two dimensional (2D) graphene-based nanomaterials with surface-to-surface architectures has been an important strategy for achieving high-performance lithium ion electrodes. However, almost all of them involve multistep procedures and expensive precursors. This paper reports a novel 2D nanocomposites composed of ultrafine SnO2 nanoparticles anchored on V2O5 nanosheets via a one-pot hydrothermal method, which exhibit high reversible capacities and rate stabilities. The enhanced electrochemical performances compared to pure SnO2 nanoparticles have been attributed to the effective prevention of self-agglomerations of the pulverized nanograins upon cycling. We speculate that the 2D V2O5 nanosheets with layered structures maybe a good substitute for the graphene nanosheets.

Ultrafine SnO2 nanoparticles as a high performance anode material for lithium ion battery

In this paper, the ultrafine tin oxides (SnO2) nanoparticles are fabricated by a facile microwave hydrothermal method with the mean size of only 14nm. Phase compositions and microstructures of the as-prepared nanoparticles have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the ultrafine SnO2 nanoparticles are obtained to be the pure rutile-structural phase with the good dispersibility. Galvanostatic cycling and cyclic voltammetry results indicate that the first discharge capacity of the ultrafine SnO2 electrode is 1196.63mAhg−1, and the reversible capacity could retain 272.63mAh g−1 at 100mAg−1 after 50 cycles for lithium ion batteries (LIBs). The excellent electrochemical performance of the SnO2 anode for LIBs is attributed to its ultrafine nanostructure for providing active sites during lithium insertion/extraction processes. Pulverization and agglomeration of the active materials are effectively reduced by the microwave hydrothermal method.

Microwave-Assisted Hydrothermal Preparation of SnO2/MoS2 Composites and their Electrochemical Performance

We introduce a two-step hydrothermal and microwave method to prepare novel SnO2/MoS2 composites. The as-prepared samples are well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The experimental results indicate that the SnO2/MoS2 composites are composed of MoS2 nanosheets and ultrafine SnO2 nanoparticles with mean size of 3–4[Formula: see text]nm which are well-distributed and anchored on the surface of MoS2 nanosheets. The resultant composites demonstrate prominently improved electrochemical performances, which could be attributed to the unique and robust microstructures and synergetic effect between MoS2 and SnO2.

Ultrafine SnO2 nanoparticles encased in graphene oxide nanoribbons for high-performance lithium ion batteries

A hierarchical hybrid of SnO2 nanoparticles encased in graphene oxide nanoribbons (GONRs) are synthesized by a facile, scalable and green method. The effect of different ratio of Sn2+/GONRs in microstructure and electrochemical performance is studied systematically. Both scanning electron microscopy images and transmission electron microscopy images show that SnO2 nanoparticles are anchored onto the surface of GONRs and encased by GONRs to form an integrative framework firmly. The hybrid demonstrated an outstanding rate capability and cycling stability. The highest discharge capacity can reach 514mAhg−1 at rates of 2000mAg−1. Even after 300 cycles, the reversible capacity remains 452mAhg−1 with a retention of 62.7% at current density of 1000mAg−1, which can be attributed to the synergetic effects of SnO2 encased in GONRs.

SnO2@N‐Doped Carbon Hollow Nanoclusters for Advanced Lithium‐Ion Battery Anodes

AbstractA facile method to synthesize novel monodispersed SnO2@N‐doped carbon hollow nanoclusters as a high‐performance anode material for lithium‐ion batteries was explored. The uniqueness of this structure results from the large amount of ultrafine small SnO2 nanoparticles, the hollow interior space, and the continuous N‐doped carbon shells, which successfully buffer problems associated with huge volume changes and guarantee electrical connectivity. All of these features make the nanocomposite well fitted for lithium storage. As a result, the electrochemical performance of monodispersed SnO2@N‐doped carbon hollow nanoclusters as an anode in lithium‐ion batteries is significantly improved, as it shows high initial discharge and charge capacities of 1572 and 1003 mA h g–1, respectively. Importantly, nearly 100 % discharge/charge efficiency is maintained during 100 consecutive cycles with a specific capacity above 910 mA h g–1.

Carbon coated SnO2 nanoparticles anchored on CNT as a superior anode material for lithium-ion batteries.

Hierarchically structured carbon coated SnO2 nanoparticles well-anchored on the surface of a CNT (C-SnO2/CNT) material were synthesized by a facile hydrothermal process and subsequent carbonization. The as-obtained C-SnO2/CNT hybrid, when applied as an anode material for lithium ion batteries (LIBs), showed a high reversible capacity up to 1572 mA h g(-1) at 200 mA g(-1) with a superior rate capability (685 mA h g(-1) at 4000 mA g(-1)). Even after 100 charge/discharge cycles at 1000 mA g(-1), a specific capacity of 1100 mA h g(-1) can still be maintained. Such impressive electrochemical performance can be mainly attributed to the hierarchical sandwiched structure and strong synergistic effects of the ultrafine SnO2 nanoparticles and the carbon coating, and thus presents this material a promising anode material for LIBs.