Multi-yolk-shell SnO2/Co3Sn2@C Nanocubes with High Initial Coulombic Efficiency and Oxygen Reutilization for Lithium Storage

Tuning Dimensions of Complexes through Selective In Situ Reaction, Mechanistic Insights into Ni(II)-Catalyzed Br-OH Exchange, Magnetic Properties, and Density Functional Theory Studies

Two coordination polymers (CPs), namely, [Mn₃(L)₂(4,4'-bipy)₂(H₂O)₂]_n (1) and [Ni(L₁)(1,4-bib)(H₂O)]_n (2) (H₃L = 5-(3-bromo-4-carboxyphenoxy)isophthalic acid, H₂L₁ = 5-(3-hydroxyphenoxy)isophthalic acid, 4,4'-bpy = 4,4'-bipyridine, and 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene), were synthesized under hydrothermal conditions. Most notably, with the help of the bromine atom-inducing effect, ligand transformation was observed in the structure of complex 2, which was scrutinized thoroughly by single crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS). Strikingly, Ni(II) ions were utilized as both coordinated atoms and as a catalyst for in situ Br-OH exchange of H₃L in the process, as a result of which the product would have preferred to form a one-dimensional chain. The same reaction cannot happen in 1, leading to form a two-dimensional structure. Moreover, Ni(II)-catalyzed and magnetic exchange mechanisms were well interpreted using density functional theory (DFT) calculations. Finally, complexes 1-2 show three-dimensional (3D) supramolecular structures because of intermolecular weak interactions (C-Br···π, C-H···π, C-H···O, and π···π stacking) and exhibit utterly different antiferrimagnetic coupling interactions.

Fabrication of MnSe/SnSe@C heterostructures for high-performance Li/Na storage

Novel heterostructured MnSe/SnSe@C nanoboxes display excellent electrochemical performance.

One-step in situ formation of 3D hollow sphere-like V2O5 incorporated Ni3V2O8 hybrids with enhanced photocatalytic performance

3-D hollow sphere-like Ni₃V₂O₈ immobilizing V₂O₅ nanoparticles were successfully synthesized via in situ recrystallization method without any template. The compact contact between V₂O₅ and Ni₃V₂O₈ ensuring the photo-inducted carriers fast transport, which would be beneficial for inhibiting recombination rate of electron-hole (e^-/h⁺) pairs. Moreover, the hollow sphere-like structure composed of the smaller nanoparticle could effectively improve of visible light capture capacity (multiple scattering for hollow architectures). Benefiting the synergistic promoting effect of the suitable heterojunction and the fascinating 3D hollow feature, the V₂O₅@Ni₃V₂O₈ indicated significantly degradation performance when evaluated as photocatalyst for degradation antibiotics and chlorophenols under visible light irradiation. Impressively, the 2-V₂O₅@Ni₃V₂O₈ heterojunction deliver the optimal degradation efficiency for TC (OTC) and 2,4-DCP (4-CP) were 90.0% (~91.2%) and 92.6% (~90.0%), respectively. The appearance mechanism for the enhancement photocatalytic performance was also elucidated in detail. The facile strategy provides a novel insight into the designing of the photocatalyst with advantages of charges separation and light-harvesting for degradation of contaminants in wastewater.

Nitrogen and boron doped carbon layer coated multiwall carbon nanotubes as high performance anode materials for lithium ion batteries

Lithium ion batteries (LIBs) are at present widely used as energy storage and conversion device in our daily life. However, due to the limited power density, the application of LIBs is still restricted in some areas such as commercial vehicles or heavy-duty trucks. An effective strategy to solve this problem is to increase energy density through the development of battery materials. At the same time, a stable long cycling battery is a great demand of environmental protection and industry. Herein we present our new materials, nitrogen and boron doped carbon layer coated multiwall carbon nanotubes (NBC@MWCNTs), which can be used as anodes for LIBs. The electrochemical results demonstrate that the designed NBC@MWCNTs electrode possesses high stable capacity over an ultra-long cycling lifespan (5000 cycles) and superior rate capability even at very high current density (67.5 A g⁻¹). Such impressive lithium storage properties could be ascribed to the synergistic coupling effect of the distinctive structural features, the reduced diffusion length of lithium ions, more active sites generated by doped atoms for lithium storage, as well as the enhancement of the electrode structural integrity. Taken together, these results indicate that the N, B-doped carbon@MWCNTs materials may have great potential for applications in next-generation high performance rechargeable batteries.

Core-shell GaP@C nanoparticles with a thin and uniform carbon coating as a promising anode material for rechargeable lithium-ion batteries

Transition metal phosphides are used as anode materials for lithium-ion batteries because of their high theoretical capacity and low polarization. In this work, a core-shell GaP@C nanocomposite was successfully synthesized by a simple chemical vapor deposition (CVD) method, utilizing commercial GaP as the raw material and xylene as the carbon source. The uniform thin carbon shell could alleviate the volumetric variation and improve the conductivity of the inner GaP. When used as an anode in lithium-ion batteries, the GaP@C nanocomposite has a capacity of 812 mA h g-1 at a current density of 0.5 A g-1 after 100 cycles. At a high current density of 2 A g-1, the GaP@C anode delivers a good capacity value of 1087 mA h g-1.

The efficient degradation of sulfisoxazole by singlet oxygen (1O2) derived from activated peroxymonosulfate (PMS) with Co3O4-SnO2/RSBC

Co₃O₄-SnO₂/rice straw biochar (RSBC) was prepared for the first time via calcining oxalate precipitation precursor dispersed on the surface of RSBC and used as a catalyst for activating PMS to degrade sulfisoxazole (SIZ). The results demonstrated that Co₃O₄-SnO₂/RSBC possessed much better catalytic performance than Co₃O₄, Co₃O₄-SnO₂, Co₃O₄/RSBC, and SnO₂/RSBC, which is ascribed to the synergy of Co₃O₄, SnO₂ and RSBC. Approximately 98% of SIZ (50 mg/L) was decomposed by PMS (1 mmol/L) activated with Co₃O₄-SnO₂/RSBC (0.1 g/L) within 5 min. The optimal degradation efficiency of SIZ was realized at the initial pH 9. Co₃O₄-SnO₂/RSBC also displayed remarkable stability and reusability, and the degradation rate of SIZ maintained over 90% even after the fifth recycle run. The electron paramagnetic resonance (EPR) technique and quenching experiments proved singlet oxygen (¹O₂) to be the main reactive oxygen species (ROS) responsible for the SIZ decomposition in the Co₃O₄-SnO₂/RSBC/PMS system. On the basis of the characterization analysis, the identification of the ROS and the SIZ degradation products, the possible mechanism and pathways of the SIZ degradation by a combination of PMS and Co₃O₄-SnO₂/RSBC were further proposed. This study provides not only a new insight into non-radical mechanism for the heterogeneous activating PMS over Co₃O₄-SnO₂/RSBC to degrade organic pollutants but also an eco-friendly synthetic route for exploring novel and efficient catalysts.

Facile synthesis of SnO2@carbon nanocomposites for lithium-ion batteries

SnO₂@C nanocomposite nanostructure approach is demonstrated, which confers shielding for volume expansion because of carbon. The SnO₂@C nanocomposite anode exhibits superior cycling stability and rate capability due to the stable electrode structure.

Co3Sn2/SnO2 nanocomposite loaded on Cu foam as high-performance three-dimensional anode for lithium-ion batteries

It is a challenge to commercialize tin dioxide-based anodes for lithium-ion batteries due to their low rate capability and poor cycling performance of the electrodes.

Low Interface Energies Tune the Electrochemical Reversibility of Tin Oxide Composite Nanoframes as Lithium-Ion Battery Anodes

The conversion reaction of lithia can push up the capacity limit of tin oxide-based anodes. However, the poor reversibility limits the practical applications of lithia in lithium-ion batteries. The latest reports indicate that the reversibility of lithia has been appropriately promoted by compositing tin oxide with transition metals. The underlying mechanism is not revealed. To design better anodes, we studied the nanostructured metal/Li₂O interfaces through atomic-scale modeling and proposed a porous nanoframe structure of Mn/Sn binary oxides. The first-principles calculation implied that because of a low interface energy of metal/Li₂O, Mn forms smaller particles in lithia than Sn. Ultrafine Mn nanoparticles surround Sn and suppress the coarsening of Sn particles. Such a composite design and the resultant interfaces significantly enhance the reversible Li-ion storage capabilities of tin oxides. The synthesized nanoframes of manganese tin oxides exhibit an initial capacity of 1620.6 mA h g^-1 at 0.05 A g^-1. Even after 1000 cycles, the nanoframe anode could deliver a capacity of 547.3 mA h g^-1 at 2 A g^-1. In general, we demonstrated a strategy of nanostructuring interfaces with low interface energy to enhance the Li-ion storage capability of binary tin oxides and revealed the mechanism of property enhancement, which might be applied to analyze other tin oxide composites.

A Review: Enhanced Anodes of Li/Na-Ion Batteries Based on Yolk-Shell Structured Nanomaterials

Lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have received much attention in energy storage system. In particular, among the great efforts on enhancing the performance of LIBs and SIBs, yolk-shell (YS) structured materials have emerged as a promising strategy toward improving lithium and sodium storage. YS structures possess unique interior void space, large surface area and short diffusion distance, which can solve the problems of volume expansion and aggregation of anode materials, thus enhancing the performance of LIBs and SIBs. In this review, we present a brief overview of recent advances in the novel YS structures of spheres, polyhedrons and rods with controllable morphology and compositions. Enhanced electrochemical performance of LIBs and SIBs based on these novel YS structured anode materials was discussed in detail.

Reinforcing Germanium Electrode with Polymer Matrix Decoration for Long Cycle Life Rechargeable Lithium Ion Batteries

Germanium is a promising anode material for lithium ion batteries because of its high theoretical specific capacity and low operation voltage. However, a significant challenge in using Ge-based anodes is the large volume variation during cycling that causes pulverization and capacity fade. Despite intense studies in the past decade, unsatisfactory cycling stability of the Ge-based electrodes still impedes their widespread applications. In this study, we demonstrate a high-performance electrode through the synergistic combination of a high-capacity Ge film grown on a three-dimensional current collector and an in situ formed poly(vinylidene fluoride)-hexafluoropropene/SiO₂ protective layer. Specifically, the polymer matrix is in continuous contact with the surface of the Ge shell, which provides improved mechanical and ionic transport properties. As a highlight, we present impressive cycling stability over 3000 cycles at 1 C rate with a capacity retention as high as 95.7%. Furthermore, the LiCoO₂-Ge full battery operates at an average voltage of 3.3 V at 0.5 C and maintains good electrochemical performance, suggesting great potential for applications in energy storage and conversion devices.

Heterogeneous Double-Shelled Constructed Fe3O4 Yolk-Shell Magnetite Nanoboxes with Superior Lithium Storage Performances

Among the numerous candidate materials for lithium ion batteries, ferroferric oxide (Fe₃O₄) has been extensively concerned as a prospective anode material because of its high theoretical specific capacity, abundant resources, low cost, and nontoxicity. Here, we designed and fabricated a unique yolk-shell construction by generating heterogeneous double-shelled SnO₂ and nitrogen-doped carbon on Fe₃O₄ yolk (denoted as Fe₃O₄@SnO₂@C-N nanoboxes). The yolk-shell structured Fe₃O₄@SnO₂@C-N nanoboxes have the adjustable void space, which permits the free expansion of Fe₃O₄ yolks without breaking the double shells during the lithiation/delithiation processes, avoiding the structural pulverization. Moreover, the heterogeneous double-shelled SnO₂@C-N can meaningfully improve the electronic conductivity and enhance the lithium storage performance. Two metal oxides also show the specific synergistic effect, promoting the electrochemistry reaction. As a result, this yolk-shell structured Fe₃O₄@SnO₂@C-N exhibits high specific capacity (870 mA h g^-1 at 0.5 A g^-1 after 200 cycles), superior rate capability, and long cycle life (670 mA h g^-1 at 3 A g^-1 after 600 cycles). This design and construction method can be extended to synthesize other yolk-shell nanostructured anode materials with improved electrochemistry performance.

Uniform core–shell Cu6Sn5@C nanospheres with controllable synthesis and excellent lithium storage performances

Well-proportioned PANI-derived carbon shells effectively limit the agglomeration of Cu₆Sn₅ nanocores and hence present extraordinary lithium storage performances.