Ultrafast Lithium Storage Using Antimony-Doped Tin Oxide Nanoparticles Sandwiched between Carbon Nanofibers and a Carbon Skin

One-dimensional carbon based nanoreactor fabrication by electrospinning for sustainable catalysis

An efficient and economical electrocatalyst as kinetic support is key to electrochemical reactions. For this reason, chemists have been working to investigate the basic changing of chemical principles when the system is confined in limited space with nanometer-scale dimensions or sub-microliter volumes. Inspired by biological research, the design and construction of a closed reaction environment, namely the reactor, has attracted more and more interest in chemistry, biology, and materials science. In particular, nanoreactors became a high-profile rising star and different types of nanoreactors have been fabricated. Compared with the traditional particle nanoreactor, the one-dimensional (1D) carbon-based nanoreactor prepared by the electrospinning process has better electrolyte diffusion, charge transfer capabilities, and outstanding catalytic activity and selectivity than the traditional particle catalyst which has great application potential in various electrochemical catalytic reactions.

Hydrothermal synthesis and characterization of the antimony-tin oxide nanomaterial and its application as a high-performance asymmetric supercapacitor, photocatalyst, and antibacterial agent

We have synthesized antimony-tin oxide (ATO) nanoparticles chemically for use in antibacterial, photocatalytic, and supercapacitor applications. The XRD pattern reveals the hexagonal structure, while the FTIR spectra validate the functional groups. The agglomerated nanostructures, which are 40-50 nm thick and 100 nm long, are shown in the SEM images as having spherical, cube, square, and rod form morphologies. In a DLS test, ATO has a zeta potential of 28.93/-28.00 mV, demonstrating strong colloidal stability in the suspension. With minimum inhibitory concentrations (MIC) ranging from 25 to 100 g mL-1, ATO is also tested for its antibacterial activity against a variety of Gram-positive and Gram-negative bacteria. Additionally, rhodamine dye was broken down by ATO nanoparticles in 240 minutes with a degradation efficiency of 88 percent. The specific capacitance (C s) and energy density (E) values of ATO nanoparticles further demonstrated their suitability for use in supercapacitors.

A quasi-3D Sb2S3/reduced graphene oxide/MXene (Ti3C2Tx) hybrid for high-rate and durable sodium-ion batteries

Antimony sulfide (Sb₂S₃) is a promising anode material for sodium-ion batteries (SIBs) owing to its high theoretical capacity and superior reversibility. However, its cycling life and rate performance are seriously impeded by the inferior inherent electroconductibility and tremendous volume change in the charging/discharging processes. Herein, a quasi three-dimensional (3D) Sb₂S₃/RGO/MXene composite, with Sb₂S₃ nanoparticles (∼15 nm) uniformly distributed in the quasi-3D RGO/MXene architecture, was prepared by a toilless hydrothermal treatment. The RGO/MXene conductive substrate not only alleviates the volume expansion of Sb₂S₃, but also promotes electrolyte infiltration and affords highways for ion/electron transport. More importantly, the synergistic effects between RGO and Ti₃C₂T_x MXene are extremely favourable to maintain the integrity of the electrode during cycling. As a result, the Sb₂S₃/RGO/MXene composite exhibits a high reversible capacity of 633 mA h g^-1 at 0.2 A g^-1, outstanding rate capability (510.1 mA h g^-1 at 4 A g^-1) and good cycling performance with a capacity loss of 16% after 500 cycles.

Interfacial Engineering of a Heteroatom-Doped Graphene Layer on Patterned Aluminum Foil for Ultrafast Lithium Storage Kinetics

The design of the interfacial architecture between the electrode and the current collector in lithium-ion batteries (LIB) plays a key role in achieving ultrafast lithium storage kinetics with respect to efficient charge transfer and cycle stability. However, in recent years, despite considerable efforts in the structural and chemical engineering of active materials (anode and cathode materials), interfacial architectures between the electrode and the current collector have received relatively insufficient attention in the case of ultrafast LIBs. Here, the interface architecture of a micropatterned Al current collector with a heteroatom-doped graphene interfacial layer is developed using roll pressing and dip coating processes. The cathode electrode fabricated with the resultant current collector offers increased contact area with enhanced interfacial stability between the electrode and the current collector because of micropatterns with heteroatom-doped graphene formed on the current collector, leading to outstanding ultrafast cycling capacity (105.8 mA h g^-1) at 20 C. Furthermore, at extremely high rate and long-term cycling performance, significant ultrafast cycling stability (specific capacity of 87.1 mA h g^-1 with capacity retention of 82.3% at 20 C after 1000 cycles) is noted. These improved ultrafast and ultra-stable performances are explained in terms of the increased electron collection/provision site with a high contact area between the electrode and the current collector for enhanced ultrafast cycling capacity and the effective corrosion prevention of the current collector with fast charge transfer for ultrafast cycling stability.

Tin Oxide Based Nanomaterials and Their Application as Anodes in Lithium-Ion Batteries and Beyond

Herein, recent progress in the field of tin oxide (SnO2 )-based nanosized and nanostructured materials as conversion and alloying/dealloying-type anodes in lithium-ion batteries and beyond (sodium- and potassium-ion batteries) is briefly discussed. The first section addresses the importance of the initial SnO2 micro- and nanostructure on the conversion and alloying/dealloying reaction upon lithiation and its impact on the microstructure and cyclability of the anodes. A further section is dedicated to recent advances in the fabrication of diverse 0D to 3D nanostructures to overcome stability issues induced by large volume changes during cycling. Additionally, the role of doping on conductivity and synergistic effects of redox-active and -inactive dopants on the reversible lithium-storage capacity and rate capability are discussed. Furthermore, the synthesis and electrochemical properties of nanostructured SnO2 /C composites are reviewed. The broad research spectrum of SnO2 anode materials is finally reflected in a brief overview of recent work published on Na- and K-ion batteries.

A Novel Conductive Mesoporous Layer with a Dynamic Two-Step Deposition Strategy Boosts Efficiency of Perovskite Solar Cells to 20

Lead halide perovskite solar cells (PSCs) with the high power conversion efficiency (PCE) typically use mesoporous metal oxide nanoparticles as the scaffold and electron-transport layers. However, the traditional mesoporous layer suffers from low electron conductivity and severe carrier recombination. Here, antimony-doped tin oxide nanorod arrays are proposed as novel transparent conductive mesoporous layers in PSCs. Such a mesoporous layer improves the electron transport as well as light utilization. To resolve the common problem of uneven growth of perovskite on rough surface, the dynamic two-step spin coating strategy is proposed to prepare highly smooth, dense, and crystallized perovskite films with micrometer-scale grains, largely reducing the carrier recombination ratio. The conductive mesoporous layer and high-quality perovskite film eventually render the PSC with a remarkable PCE of 20.1% with excellent reproducibility. These findings provide a new avenue to further design high-efficiency PSCs from the aspect of carrier transport and recombination.

Improved Ionic Diffusion through the Mesoporous Carbon Skin on Silicon Nanoparticles Embedded in Carbon for Ultrafast Lithium Storage

Because of their combined effects of outstanding mechanical stability, high electrical conductivity, and high theoretical capacity, silicon (Si) nanoparticles embedded in carbon are a promising candidate as electrode material for practical utilization in Li-ion batteries (LIBs) to replace the conventional graphite. However, because of the poor ionic diffusion of electrode materials, the low-grade ultrafast cycling performance at high current densities remains a considerable challenge. In the present study, seeking to improve the ionic diffusion, we propose a novel design of mesoporous carbon skin on the Si nanoparticles embedded in carbon by hydrothermal reaction, poly(methyl methacrylate) coating process, and carbonization. The resultant electrode offers a high specific discharge capacity with excellent cycling stability (1140 mA h g^-1 at 100 mA g^-1 after 100 cycles), superb high-rate performance (969 mA h g^-1 at 2000 mA g^-1), and outstanding ultrafast cycling stability (532 mA h g^-1 at 2000 mA g^-1 after 500 cycles). The battery performances are surpassing the previously reported results for carbon and Si composite-based electrodes on LIBs. Therefore, this novel approach provides multiple benefits in terms of the effective accommodation of large volume expansions of the Si nanoparticles, a shorter Li-ion diffusion pathway, and stable electrochemical conditions from a faster ionic diffusion during cycling.

Novel Silicon Doped Tin Oxide-Carbon Microspheres as Anode Material for Lithium Ion Batteries: The Multiple Effects Exerted by Doped Si

Silicon doped tin oxide embedded porous carbon microspheres (Si_y Sn_1-y O_x @C) are synthesized. It is found that the doped Si not only improves the reversibility of lithiation/delithiation reactions, but also prevents Sn from aggregation. In addition, the doped Si introduces extra defects into the carbon matrix and produces Li⁺ conductive Li₄ SiO₄ , which accelerates Li⁺ diffusion. Together with the conductive, porous carbon matrix that provides void space to accommodate the volume change of Sn during charge/discharge cycling, the novel Si_y Sn_1-y O_x @C exhibits excellent electrochemical performance. It shows a high initial columbic efficiency of 75.9%. A charge (delithiation) capacity of 880.32 mA h g^-1 is retained after 150 cycles, i.e., 91% of the initial capacity. These results indicate that the as-synthesized Si_y Sn_1-y O_x @C is a promising anode material for lithium ion batteries.