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Tin oxides are the most promising anode materials for sodium-ion batteries (SIBs) owing to their abundance and their multi-electron reactions, which ultimately provide a high theoretical capacity. However, the huge volume expansion and consequent stability issues of tin and tin oxide anodes have relentlessly hindered their application in Na-ion batteries. To overcome these drawbacks, we present a facile strategy to prepare a non-metal-doped Sn3O4 anode by facile hydrothermal route and the investigation of its sodium-ion storage performance. B-F@Sn3O4 exhibits a triclinic structure with nanoflake morphology, length of 40–100 nm, and thickness of 10–15 nm. When applied as the anode material for SIBs, the resultant material exhibits excellent sodium-ion storage abilities in terms of cycling stability and high rate capability. In SIBs, the Sn3O4 anode capacity was observed to be 732.8 mA h g−1 at a current density of 50 mA g−1, and good cycling performance at 200 mA g−1 with a capacity retention of 77.5% after 120 cycles. Furthermore, the diffusion coefficients of the sodium ions calculated based on EIS measurements were observed to be in the range of 10−13 to 10−11 cm2 s−1, which reveals the admirable diffusion mobility of Na atoms in the Sn3O4 nanoflakes. Moreover, a coin-type sodium-ion full cell consisting of the B-F@Sn3O4 anode and a Na3V2(PO4)3 cathode exhibited a capacity of 81.2 mA h g−1 at C/20. This study demonstrates that the Sn3O4 is a promising anode material for SIBs. Thus, the B-F-doped Sn3O4 material assembled by interconnected nanoflakes is capable of providing fast carrier transmission dynamics and outstanding structural integrity, suggesting the feasibility of the current framework for sodium-ion storage. [ABSTRACT FROM AUTHOR]

In the present work, we have demonstrated the synthesis of Molybdenum Carbide‐reduced graphene oxide (Mo2C‐rGO) heterostructure. Uniquely, the in‐situ formation of rGO using D‐glucose in the heterostructure and its battery performance has been discussed. The High Resolution Transmission Electron Microscopy (HR‐TEM) study clearly shows the growth of Mo2C nanoparticles along with rGO confers a unique integrated layered heterostructure. X‐ray diffraction (XRD) and Raman study exhibits the formation of graphene oxide (GO) followed by multi‐layers of rGO along with hexagonal Mo2C. The electrochemical study of Mo2C‐rGO heterostructure demonstrates stable cycling performance and excellent rate capabilities. The heterostructure showed the initial capacity (1st discharge) around 632.23 mAh/g and specific capacity i. e., 537.91 mAh/g @ 0.5 A/g with 99–100 % columbic efficiency. The reversible capacities of 521.56 mAh/g, and 400.76 mAh/g were observed at current densities of 1 A/g and 2 A/g for 300 cycles, respectively, which justifies the stability of heterostructure. The cycled cell was investigated by using Electrochemical Imepedance Spectroscopy (EIS), ex‐situ XRD, and Field Emmision Scanning Electron microscopy (FESEM), which shows the negligible change in the ionic conductivity, structure, and morphology after 300 cycles. It shows the excellent stability of Mo2C‐rGO heterostructure. [ABSTRACT FROM AUTHOR]

SnO2@C nanocomposites were synthesized using a citrate gel method in one step. Carbon has been used to increase the conductivity of pristine SnO2. The SnO2@C nanocomposites show nanoparticles sized in the range of 30–50 nm. A structural study by XRD shows the tetragonal rutile structure of SnO2. Furthermore, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirm the existence of SnO2 along with carbon. The electrochemical performance was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge measurements. The nanocomposite has been used as an anode material for lithium-ion batteries. Pristine SnO2 exhibited a discharge capacity of 1854 mA h g−1 and a corresponding charge capacity of 1038 mA h g−1 for the first cycle. The SnO2@C nanocomposite showed a discharge capacity of 2574 mA h g−1 and charge capacity of 1481 mA h g−1 for the first cycle. These results clearly show the effect of carbon incorporation in SnO2. Furthermore, the nanocomposite shows a discharge capacity as high as 725 mA h g−1 after 200 cycles at a current density of 50 mA g−1. Thus, the obtained capacity for the nanocomposites is much higher as compared to that for pristine SnO2, i.e., 119 mA h g−1 at 50 mA g−1 after 200 cycles. The higher capacity in the nanocomposites is due to the fast transport of electrons and easy transport of lithium ions due to the carbon in the nanocomposites. The SnO2@C nanocomposite anode exhibits superior cycling stability and rate capability due to its stable electrode structure. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis of fragmented lignin (FL) assisted zinc oxide (ZnO) and titanium oxide (TiO2) nanocomposites. The fragmented lignin synthesized from biomass (sugarcane bagasse) was used as a template to generate the morphology and crystallite structure of metal oxide nanomaterial. The nanocomposites were synthesized by a simple precipitation method, wherein fragmented lignin is used in alkaline medium as a template. X-ray diffraction (XRD) analysis shows the phase formation of hexagonal wurtzite ZnO and mixed phase formation of TiO2 as rutile and anatase. The morphology was studied by using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). The FE-SEM of pristine ZnO nanocomposites showed a cluster of particles whereas FL-ZnO NPs showed self-aligned nanoparticles in the form of rod shaped having average size 30-70 nm. Pristine TiO2 nanoparticles showed clusters of particles and FL-TiO2 nanocomposites showed well crystalline 41nm size nanocomposites. The FL acts as a surfactant which restrict the cluster formations. The band gap determined by diffuse reflectance spectra is 3.10 eV and 3.20 eV for FL-ZnO and FL-TiO2 nanocomposites, respectively. Photoluminescence spectra of both nanocomposites showed structural defects in the visible region. Further, the antimicrobial activity of pristine ZnO and TiO2 nanoparticles, and FL-ZnO and FL-TiO2 nanocomposites against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) were studied under UV-A (315-400 nm) (8W) for 30min. [ABSTRACT FROM AUTHOR]

Herein, we report Sn 3 O 4 and Sn 3 O 4 nanoflake/graphene for photocatalytic hydrogen generation from H 2 O and H 2 S under natural "sunlight" irradiation. The Sn 3 O 4 /graphene composites were prepared by a simple hydrothermal method at relatively low temperatures (150 °C). The incorporation of graphene in Sn 3 O 4 exhibits remarkable improvement in solar light absorption, with improved photoinduced charge separation due to formation of the heterostructure. The highest photocatalytic hydrogen production rate for the Sn 3 O 4 /graphene nanoheterostructure was observed as 4687 μmol h -1 g -1 from H 2 O and 7887 μmol h -1 g -1 from H 2 S under natural sunlight. The observed hydrogen evolution is much higher than that for pure Sn 3 O 4 (5.7 times that from H 2 O, and 2.2 times from H 2 S). The improved photocatalytic activity is due to the presence of graphene, which acts as an electron collector and transporter in the heterostructure. More significantly, the Sn 3 O 4 nanoflakes are uniformly and parallel grown on the graphene surface, which accelerates the fast transport of electrons due to the short diffusion distance. Such a unique morphology for the Sn 3 O 4 along with the graphene provides more adsorption sites, which are effective for photocatalytic reactions under solar light. This work suggests an effective strategy towards designing the surfaces of various oxides with graphene nanoheterostructures for high performance of energy-conversion devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A SnO 2 /Ni/CNT nanocomposite was synthesized using a simple one-step hydrothermal method followed by calcination. A structural study via XRD shows that the tetragonal rutile structure of SnO 2 is maintained. Further, X-ray photoelectron spectroscopy (XPS) and Raman studies confirm the existence of SnO 2 along with CNTs and Ni nanoparticles. The electrochemical performance was investigated via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements. The nanocomposite has been used as an anode material for lithium-ion batteries. The SnO 2 /Ni/CNT nanocomposite exhibited an initial discharge capacity of 5312 mA h g -1 and a corresponding charge capacity of 2267 mA h g -1 during the first cycle at 50 mA g -1 . Pristine SnO 2 showed a discharge/charge capacity of 1445/636 mA h g -1 during the first cycle at 50 mA g -1 . This clearly shows the effects of the optimum concentrations of CNTs and Ni. Further, the nanocomposite (SnNiCn) shows a discharge capacity as high as 919 mA h g -1 after 210 cycles at a current density of 400 mA g -1 in a Li-ion battery set-up. Thus, the obtained capacity from the nanocomposite is much higher compared to pristine SnO 2 . The higher capacity in the nanoheterostructure is due to the well-dispersed nanosized Ni-decorated stabilized SnO 2 along with the CNTs, avoiding pulverization as a result of the volumetric change of the nanoparticles being minimized. The material accommodates huge volume expansion and avoids the agglomeration of nanoparticles during the lithiation and delithiation processes. The Ni nanoparticles can successfully inhibit Sn coarsening during cycling, resulting in the enhancement of stability during reversible conversion reactions. They ultimately enhance the capacity, giving stability to the nanocomposite and improving performance. Additionally, the material exhibits a lower Warburg coefficient and higher Li ion diffusion coefficient, which in turn accelerate the interfacial charge transfer process; this is also responsible for the enhanced stable electrochemical performance. A detailed mechanism is expressed and elaborated on to provide a better understanding of the enhanced electrochemical performance., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Constructing a heterostructure is an effective strategy to reduce the electron-hole recombination rate, which enhances photocatalytic activity. Here, we report a facile hydrothermal method to grow CdS nanoparticles on MnWO 4 nanorods and their photocatalytic hydrogen generation under solar light. A structural study shows the decoration of hexagonal CdS nanoparticles on monoclinic MnWO 4 . Morphological studies based on FE-TEM analysis confirm the sensitization of CdS nanoparticles (10 nm) on MnWO 4 nanorods of diameter-35 nm with mean length ∼100 nm. The lower PL intensity of MnWO 4 was observed with an increasing amount of CdS nanoparticles, which shows inhibition of the charge carrier recombination rate. A CdS@MnWO 4 narrow band gap semiconductor was employed for photocatalytic hydrogen generation from water under solar light and the highest amount of hydrogen, i.e. 3218 μmol h -1 g -1 , is obtained which is 21 times higher than that with pristine MnWO 4 . The enhanced photocatalytic activity is ascribed to the formation of a CdS@MnWO 4 nanoheterostructure resulting in efficient spatial separation of photogenerated electron-hole pairs due to vacancy defects. More significantly, direct Z-scheme electron transfer from MnWO 4 to CdS is responsible for the enhanced hydrogen evolution. This work signifies that a CdS decorated MnWO 4 nanoheterostructure has the potential to improve the solar to direct fuel conversion efficiency., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The Li 4 Ti 5 O 12 (LTO) and lithium silicate (LS) surface modified LTO have been demonstrated by a unique paper templated method. Comparative study of structural characterization with electrochemical analysis was demonstrated for pristine and modified Li 4 Ti 5 O 12 . Structural and morphological study shows the existence of the cubic spinel structure with highly crystalline 250-300 nm size particles. The LS modified LTO shows the deposition of 10-20 nm sized LS nanoparticles on cuboidal LTO. Further, X-ray photoelectron spectroscopy (XPS) confirms the existence of Li 2 SiO 3 (LS) in the modified LTO. The electrochemical performance was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge. The modified LTO with 2% LS (LTS2) exhibited excellent rate capability compare to pristine LTO i.e. 182 mA h g -1 specific capacity at a current rate, 50 mA g -1 with remarkable cycling stability up to 1100 cycles at a current rate of 800 mA g -1 . The lithium ion full cell of modified LTO with LS as an anode and LiCoO 2 as a cathode exhibited a remarkably reversible specific capacity i.e. 110 mA h g -1 . Both electronic and ionic conductivities of pristine LTO are observed to be enhanced by incorporation of appropriate amount of LS in LTO due to a larger surface contact at the interface of electrode and electrolyte. More significantly, the versatile paper templated synthesis approach of modified LTO with LS provides densely packed highly crystalline particles. Additionally, it exhibits lower Warburg coefficient and higher Li ion diffusion coefficient which in turn accelerate the interfacial charge transfer process, which is responsible for enhanced stable electrochemical performance. The detailed mechanism is expressed and elaborated for better understanding of enhanced electrochemical performance due to the surface modification., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)