Carbon-coated SnO2 Research Articles

Implementation of binder-free SnO2 NWs@C electrode and LiTFSI-based electrolyte for high-performance lithium-ion battery

This study has investigated the effect of carbon coating on the electrochemical performance of SnO2 Nanowires (NWs) as an electrode along with a bis (trifluoromethane) sulfonimide lithium (LiTFSI)-based electrolyte in a lithium-ion battery (LIB). The vapor–liquid–solid approach has been used to grow SnO2 NWs on the stainless steel mesh current collector. The obtained results have demonstrated that the utilization of the LiTFSI-based electrolyte improved the battery performance with the SnO2 NWs electrode over the LiPF6-based electrolyte. This may be due to the formation of a stable and thin solid electrolyte interphase layer. Since bare SnO2 NWs exhibit inferior cycling stability due to their high volumetric expansion and poor conductivity, incorporating carbon coating could improve performance. Although the initial discharge specific capacity obtained for the carbon-coated SnO2 NWs (SnO2 NWs@C) electrode (1328.4 mAh g−1) was in the order of the first discharge capacity for the SnO2 NWs, the SnO2 NWs@C electrode possessed capacity retention with six times improvement as compared to the pristine SnO2 NWs after 120 cycles. The Coulombic efficiency of 99% has been achieved for the SnO2 NWs@C electrode over 120 cycles. Field emission scanning electron microscopy images revealed that the carbon coating could keep the overall structure of the electrode upon cycling. It has been evidenced that the SnO2 NWs@C electrode with LiTFSI-based electrolyte has an excellent potential to implement in high-performance LIBs.

Carbon-coated SnO2 riveted on a reduced graphene oxide composite (C@SnO2/RGO) as an anode material for lithium-ion batteries.

The research on graphene-based anode materials for high-performance lithium-ion batteries (LIBs) has been prevalent in recent years. In the present work, carbon-coated SnO2 riveted on a reduced graphene oxide sheet composite (C@SnO2/RGO) was fabricated using GO solution, SnCl4, and glucose via a hydrothermal method after heat treatment. When the composite was exploited as an anode material for LIBs, the electrodes were found to exhibit a stable reversible discharge capacity of 843 mA h g−1 at 100 mA g−1 after 100 cycles with 99.5% coulombic efficiency (CE), and a specific capacity of 485 mA h g−1 at 1000 mA g−1 after 200 cycles; these values were higher than those for a sample without glucose (SnO2/RGO) and a pure SnO2 sample. The favourable electrochemical performances of the C@SnO2/RGO electrodes may be attributed to the special double-carbon structure of the composite, which can effectively suppress the volume expansion of SnO2 nanoparticles and facilitate the transfer rates of Li+ and electrons during the charge/discharge process.

Large-size carbon-coated SnO2 composite as improved anode material for lithium ion batteries

SnO2 microbelt coating carbon composite was fabricated via electrospinning precursor, thermal treatment, and polymer adhesion process. Primarily, the solvent of electrospinning jet quickly evaporates in a relatively high-temperature environment; intermediate microtubules simultaneously form when the solute containing tin salt and binder converge on the skin of the jet; then, the microtubules collapse into flat microbelt product under the action of atmospheric pressure. Subsequently, SnO2 microbelts can be obtained by annealing the electrospinning products. Finally, the SnO2@C microbelts are synthesized by dopamine polymerization and carbonization process. The SnO2@C microbelts present a regular strip with width ~ 1.2 μm and thickness ~ 120 nm. Because of the synergy effect of carbon coating and SnO2 microbelt design project, the composite shows superior lithium storage of 504 mAh g-1 after 100 cycles at 0.2 A g-1. The SnO2@C microbelts are expected to be competitive alternative anode material of next-generation LIBs.

Carbon-Coated SnO2/Ti3C2 Composites with Enhanced Lithium Storage Performance

Tin-based anode materials including oxides, composites oxides, and tin-based alloys are identified as promising candidates for energy storage attributed to the highest theoretical specific capacity. We introduce Ti3C2-MXene as structural skeletons and amorphous carbon as conductive networks for tin oxide in this work. Herein, carbon-coated kernel-like SnO2 coupling with two-dimensional (2D) layered structure Ti3C2-MXene (C@SnO2/Ti3C2) composites were prepared by a hydrothermal reaction and a further calcination process. The fabricated C@SnO2/Ti3C2 nanocomposites exhibit smaller charge transfer resistance, larger Li+ diffusion coefficient, and better cycling stability than SnO2/Ti3C2 and pure Ti3C2. Most of all, C@SnO2/Ti3C2 nanocomposites display excellent initial capacity of 1531.5 mAh g−1 at current density of 100 mA g−1 and show outstanding rate performance of 540 mAh g−1even after 200 cycles. In our work, we will provide a new research idea for the composite materials of metal oxides and two-dimensional layered materials in the field of electrode materials for batteries.

Adding lithium fluoride to improve the electrochemical properties SnO2@C/MWCNTs composite anode for lithium-ion batteries

In this paper, SnO2@C/MWCNTs‑lithium fluoride (LiF) composite electrode was prepared. Carbon-coated SnO2 (SnO2@C) was prepared by spray drying method with water-soluble asphalt as the carbon source and multiwalled carbon nanotubes (MWCNTs) as conductive agent. The electronic conductivity of the new type of anode was significantly enhanced and the volume expansion of SnO2 was refrained. LiF was utilized to enhance the stability of the SEI film and improve the coulombic efficiency and capacity retention rate of electrode. After 200 cycles, the SnO2@C/MWCNTs-LiF anode still maintain 70.1% capacity retention rate. And the specific capacity hold at 274 mAh/g at 2400 mA/g compared with 136 mAh/g of SnO2@C/MWCNTs anode. The results demonstrated that the addition of LiF can stabilize the SEI film and improve the electrochemical performance of the lithium-ion batteries (LIBs).

Asphalt-Decomposed Carbon-Coated SnO2 as an Anode for Lithium Ion Batteries

In this paper, a SnO2@C composite anode was prepared by coating SnO2 with asphalt by hydrothermal process and carbonization. The core–shell structure of SnO2 nanoparticles was characterized by scanning electron microscopy, energy-dispersive spectrometry, x-ray diffraction and thermal gravimetric analysis. The electrochemical performance tests showed the SnO2@C anode exhibited excellent cycle performance and high specific capacity. The core–shell structure can accommodate the huge volume expansion of SnO2 nanoparticles during charge/discharge. The conductivity of the electrode was also obviously enhanced. The first-charge capacity and coulombic efficiency reached 1798 mAh/g and 65%, respectively. After 80 cycles, the capacity still remained at 446 mAh/g at a current density of 100 mA/g.

Excimer ultraviolet-irradiated exfoliated graphite loaded with carbon-coated SnOx small nanoparticles as advanced anodes for high-rate-capacity lithium-ion batteries

This paper reports a fast and efficient excimer ultraviolet (EUV) radiation method to prepare carbon-coated mixed tin oxide-loaded exfoliated graphite (SnOx@C-G) nanocomposites. The SnOx small nanoparticles (SNPs) are isolated using oxidized sucrose and uniformly deposited onto mildly oxidized exfoliated graphite during the 20-minute EUV radiation process. XPS and ESR analyses suggest the existence of abundant oxygen vacancies in the SnOx SNPs. The electrochemical kinetics of SnOx@C-G, which are determined by in situ electrochemical impedance analysis, demonstrated a high reversible capacity of approximately 740 mA h g-1 after 250 cycles at a current density of 1.6 A g-1, and an impressive reversible rate performance exceeding 450 mA h g-1 can be obtained even at a high current density of 3.2 A g-1 when applied as an anode for lithium storage. This improved cycling stability and rate capability benefit from the carbon coating, which not only buffers the volume change of SnOx SNPs but also provides a path for electron transport on the surface of the SnOx SNPs during the electrochemical process. Furthermore, the oxygen vacancies in SnOx SNPs result in a large capacitive contribution to capacity. The EUV radiation method used to synthesize SnOx@C-graphite nanosheets is universally applicable to prepare a high-performance SNPs/carbon-based anode for lithium-ion batteries.

Carbon-coated SnO2@carbon nanofibers produced by electrospinning-electrospraying method for anode materials of lithium-ion batteries

Abstract In this study, carbon-coated SnO2 nanoparticles were loaded on pure carbon nanofibers ((SnO2@C)/CNFs) by the synchronized electrospinning-electrospraying method and subsequent heat treatment. Compared with SnO2@CNFs composites fabricated by conventional electrospinning method, carbon-coated SnO2 nanoparticles were homogeneously dispersed while attached tightly on CNFs surface with the help of carbon coating. The (SnO2@C)/CNFs composites delivered an outstanding initial discharge capacity of 1425 mAh g−1 at 100 mA g-1 and an initial coulombic efficiency of 63.24%. A reversible capacity of ~500 mAh g-1 was also displayed after 50 cycles. Remarkably, the outstanding electrochemical performance of (SnO2@C)/CNFs composites was ascribed to the cooperative effect of external carbon-coated SnO2 nanoparticles and unmarred CNFs three-dimensional interconnection networks. Furthermore, this synchronized electrospinning-electrospraying method was simple, efficient and scalable, providing a potential strategy for lithium-ion battery anode material production.

Hydrothermal Growth and Electrochemical Performance of Carbon-Coated Porous SnO₂ Nanospheres.

The porous SnO2 nanospheres were fabricated by hydrothermal method and then the carbon layer was coated as a buffer cushion through a facile hydrothermal process in aqueous D-glucose followed by a subsequent calcination at 500 °C in a nitrogen (N2) atmosphere. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and Raman spectra. Based on the experimental results, the thickness of carbon layer could be well-controlled by hydrothermal time and D-glucose concentration. The typical as-prepared carbon-coated porous SnO2 nanospheres show an initial discharge capacity of 711.26 mAhg-1 and a stabilized capacity at 414 mAhg-1 after 50 cycles. It was shown that the carbon-coated porous SnO2 nanospheres exhibited better electrochemical properties in terms of high Columbic efficiency and rate performance, which are attributed to the porous structure and the outer carbon layer.

Carbon-Coated Ordered Mesoporous SnO₂ Composite Based Anode Material for High Performance Lithium-Ion Batteries.

Recently, tin oxide (SnO2) has received significant attention for use as an anode material for next generation lithium-ion batteries (LIBs) owing to its high theoretical capacity (782 mAh g-1), which is more than twice of that of the commercialized graphite (372 mAh g-1). Several additional advantages, such as low cost, environmental friendliness, easy fabrication and natural abundance improve its promise. Although the theoretical capacity of SnO2 is high, volume expansion during cycling causes issue with cycling stability. In this study, an ordered mesoporous SnO2 was synthesized using a hard template (SBA-15), such that its mesoporous structure can buffer SnO2 particles from cracks caused by volume expansion. It can also allow effective electrolyte infiltration to ensure better reactivity of the active material with Li+ ions. The capacity of synthesized mesoporous SnO2 improved to 218.4 mAh g-1 compared regular SnO2 nanoparticles (69.6 mAh g-1) after 50 cycles at a rate of 0.1 C. Furthermore, carbon-coated mesoporous SnO2 enhanced capacity retention upon cycling (844.6 mAh g-1 after 50 cycles at 0.1 C) by insulating and preventing the cracking of the active material during lithiation and delithiation.

Mechanical properties of individual core-shell-structured SnO2@C nanofibers investigated by atomic force microscopy and finite element method

Although SnO2-based nanomaterials used to be considered as being extraordinarily versatile for application to nanosensors, microelectronic devices, lithium-ion batteries, supercapacitors and other devices, the functionalities of SnO2-based nanomaterials are severely limited by their intrinsic vulnerabilities. Facile electrospinning was used to prepare SnO2 nanofibers coated with a protective carbon layer. The mechanical properties of individual core-shell-structured SnO2@C nanofibers were investigated by atomic force microscopy and the finite element method. The elastic moduli of the carbon-coated SnO2 nanofibers remarkably increased, suggesting that coating SnO2 nanofibers with carbon could be an effective method of improving their mechanical properties.

Carbon materials-functionalized tin dioxide nanoparticles toward robust, high-performance nitrogen dioxide gas sensor

Carbon (C) materials, which process excellent electrical conductivity and high carrier mobility, are promising sensing materials as active units for gas sensors. However, structural agglomeration caused by chemical processes results in a small resistance change and low sensing response. To address the above issues, structure-derived carbon-coated tin dioxide (SnO2) nanoparticles having distinct core-shell morphology with a 3D net-like structure and highly uniform size are prepared by careful synthesis and fine structural design. The optimum carbon-coated SnO2 nanoparticles (SnO2/C)-based gas sensor exhibits a low working temperature, excellent selectivity and fast response-recovery properties. In addition, the SnO2/C-based gas sensor can maintain a sensitivity to nitrogen dioxide (NO2) of 3 after being cycled 4 times at 140 °C for, suggesting its good long-term stability. The structural integrity, good synergistic properties, and high gas-sensing performance of SnO2/C render it a promising sensing material for advanced gas sensors.

Confining SnS2 Ultrathin Nanosheets in Hollow Carbon Nanostructures for Efficient Capacitive Sodium Storage

Summary Tin disulfide (SnS 2 ) is a promising anode material for sodium-ion batteries because of its high specific capacity. However, the low conductivity and large volume change during reaction with Na + ions greatly limit its practical application. Herein, a multistep templating method has been exploited for the rational design and synthesis of SnS 2 nanosheets confined in carbon nanotubes (SnS 2 @CNTs). To demonstrate the universality of this method, SnS 2 nanosheets confined in carbon nanoboxes (SnS 2 @CNBs) and hollow carbon nanospheres (SnS 2 @CNSs) have also been synthesized by simply changing the template in the reaction system. Due to their unique structural merits, the SnS 2 @CNTs, SnS 2 @CNBs, and SnS 2 @CNSs show improved sodium storage performance in terms of high specific capacity, good cycling stability, and superior rate capability.

Fabrication of porous carbon sphere@SnO 2 @carbon layer coating composite as high performance anode for sodium-ion batteries

Abstract SnO 2 has triggered lots of research efforts as anode for sodium-ion batteries. However, the volume expansion and poor conductivity lead to an unsatisfactory electrochemical performance for the practical application of SnO 2 . In this work, a novel carbon-coated SnO 2 supported by porous carbon sphere composite is synthesized by hydrothermal process combining with annealing method. The porous carbon sphere@SnO 2 @carbon layer coating composite anode delivers a reversible capacity of 326 mAh g −1 over 80 cycles at a current density of 50 mA g −1 . Even at 1600 mA g −1 , a capacity of 82 mAh g −1 is still maintained after 550 cycles. Such excellent performance can be ascribed to the unique structure, which efficiently accommodates volume expansion, enhances conductivity and offers shortened sodium-ion transport pathway. The charge-storage mechanisms can be comprised of diffusion-controlled reaction and pseudocapacitance effect. At high scan rate of 1.0 mV s −1 , the capacity contribution of pseudocapacitance effect could reach as high as 78%.

Graphene nanoribbons wrapping carbon-coated SnO2 nanoparticles anchored on carbon nanotubes for high Li+ storage

Graphene nanoribbons wrapped carbon-coated SnO2 nanoparticles which are anchored on carbon nanotubes (CNTs) by a two-step hydrothermal method. In the final hybrid of graphene nanoribbons wrapping carbon-coated SnO2 nanoparticles on CNTs (GCSCNTs), SnO2 nanoparticles in the diameter of ∼5 nm are uniformly anchored on the surface of CNTs and graphene nanoribbons flexibly wrapped carbon-coated SnO2 nanoparticles on the surface. Electrochemical experiments proved that GCSCNTs exhibited superior lithium storage capacity and cycling performance. The GCSCNTs showed a reversible capacity of 1038 mA h g−1 at a current density of 0.1 A g−1 and keep the specific capacity of 502 mA h g−1 at the current density of 1 A g−1 over1000 cycles.

Hierarchically porous carbon-coated SnO2@graphene foams as anodes for lithium ion storage

Graphene-based hierarchically porous materials have exhibited enormous potentials in high-performance lithium-ion batteries. However, the electrochemical performance of these materials is hampered due to the detachment of active materials from graphene upon long-term cycling. Therefore, the interfacial design between active materials and graphene is crucial for their high performance in lithium-ion storage. In this study, a hierarchically porous architecture of spatially confining carbon-coated SnO2 nanospheres (C-SnO2 NSs) within graphene foam has been designed and fabricated by employing the H-bonding effect of sodium carboxymethyl cellulose to bridge the C-SnO2 NSs and graphene sheets in a complete encapsulation arrangement. The as-fabricated architecture not only prevents the detachment of C-SnO2 from graphene and direct exposure of them in electrolyte, but also suppresses the electrode's pulverization caused by the large volume change of SnO2 during charge/discharge processes, thus achieving SnO2 interfacial and structural stability. Moreover, benefiting from the hierarchical porosity and interconnected graphene network, electrode reaction kinetics is greatly enhanced. As a result of these merits, the as-built electrode shows extraordinary rate capability (611.1 mA h g−1 at 4.0 A g−1; 427.9 mA h g−1 at 8.0 A g−1) and robust cycling stability (1458.8 mA h g−1 remaining after 700 cycles at 1.0 A g−1).

Effect of pore distribution on the lithium storage properties of porous C/SnO 2 nanofibers

Abstract Carbon-coated SnO 2 composite nanofibers has been considered as an efficient way to alleviate the enormous volume change problem of tin-based anodes for lithium ion batteries (LIBs). Herein, porous carbon/SnO 2 nanofibers were prepared via single-needle electrospinning which was followed by carbonization treatment. The procedure involved two categories of precursors of SnO 2, stannic chloride pentahydrate and stannic acetate, whereas former was fully dissolved while later was partially dissolved in solvent, leading to different pore distribution in cooperating with thermal decomposition of polymethyl methacrylate. The pores generated from stannic chloride pentahydrate/polymethyl methacrylate system were randomly distributed on the surface of nanofibers. In the case of stannic acetate/polymethyl methacrylate derived composites, the thermolysis of polymer left multichannels within the nanofibers coupled with SnO 2 nanoparticles. Galvanostatic charge/discharge was carried out to evaluate them as anode materials for LIBs. It was found that multichannel carbon/SnO 2 nanofibers with large specific surface area (34.97 m 2 /g) achieved better rate capability and stable capacity retention of 89.9% after 50 cycles. The longitudinally aligned pores facilitated lithium diffusion and transference, which avoided nonuniform deposition and separation of lithium ions, thereby further enhancing the stability during the discharge/charge process.

Graphene-based carbon coated tin oxide as a lithium ion battery anode material with high performance

A ternary rGO/PC/SnO2nanocomposite with carbon-coated SnO2homogeneously grown on the surface of rGO using glucose as the soft templating agent delivers an initial specific discharge capacity of 2238.2 mA h g−1and retains 1467.8 mA h g−1after 150 cycles at 0.1C (1C = 782 mA g−1). Even at 1C after 200 cycles, the specific capacity is 618.3 mA h g−1.

Enhanced Cycling Properties of Carbon-Coated SnO<SUB>2</SUB>–Co<SUB>3</SUB>O<SUB>4</SUB> Composite Nanowires for Lithium-Ion Batteries

Enhanced Cycling Properties of Carbon-Coated SnO<SUB>2</SUB>–Co<SUB>3</SUB>O<SUB>4</SUB> Composite Nanowires for Lithium-Ion Batteries

Enhanced cycle stability of polypyrrole-derived nitrogen-doped carbon-coated tin oxide hollow nanofibers for lithium battery anodes

SnO2 hollow nanofibers (SnO2 hNFs) are prepared through electrospinning and annealing processes. The polypyrrole layers coated onto the surface of the SnO2 hNFs are annealed in a nitrogen atmosphere. The nitrogen-doped carbon-coated SnO2 hNFs (SnO2/NC hNFs) are composed of SnO2 hNFs with a wall thickness of 60–80 nm and a nitrogen-doped carbon layer ∼10 nm thick. The nitrogen content in the carbon layer is approximately 7.95%. Owing to the nitrogen-doped carbon shell layers, the specific reversible capacity of SnO2/NC hNFs at a current density of 0.2 A g−1 after 100 cycles is 1648 mAh g−1, which is 427% higher than that of (386 mAh g−1) SnO2 hNFs. This strategy may open new avenues for the design of other composite architectures as electrode materials in order to achieve high-performance lithium ion batteries.