Li-cycling properties of molten salt method prepared nano/submicrometer and micrometer-sized CuO for lithium batteries

Facile synthesis of nanosized Mn3O4 powder anodes for high capacity Lithium-Ion battery via flame spray pyrolysis

Mn₃O₄ powders with nanometer size are successfully synthesized by a simple one-step method via flame spray pyrolysis. The precursor droplet is generated by heating under high temperature flame with fixed flow rate, and the exothermic reaction is induced to form nanosized Mn₃O₄ powders. When used as anode material for lithium-ion battery, the Mn₃O₄ exhibits good cycling capacity and rate performance. It delivers a specific capacity of 1,182 mA h g⁻¹ over 110 cycles at a current density of 200 mA g⁻¹, and has a high capacity of 140 mA h g⁻¹ at 5,000 mA g⁻¹.

New rationally designed hybrid polypyrrole@SnCoS4 as an efficient anode for lithium-ion batteries

Three active materials containing binary metal sulfide (SnCoS₄) were obtained via a simple hydrothermal method. Also, the electrochemical performance of the anode materials was investigated in a lithium-ion half-cell.

Biomass-Derived Graphitic Carbon Encapsulated Fe/Fe3C Composite as an Anode Material for High-Performance Lithium Ion Batteries

Lithium ion (Li-ion) batteries have been widely applied to portable electronic devices and hybrid vehicles. In order to further enhance performance, the search for advanced anode materials to meet the growing demand for high-performance Li-ion batteries is significant. Fe3C as an anode material can contribute more capacity than its theoretical one due to the pseudocapacity on the interface. However, the traditional synthetic methods need harsh conditions, such as high temperature and hazardous and expensive chemical precursors. In this study, a graphitic carbon encapsulated Fe/Fe3C (denoted as Fe/Fe3C@GC) composite was synthesized as an anode active material for high-performance lithium ion batteries by a simple and cost-effective approach through co-pyrolysis of biomass and iron precursor. The graphitic carbon shell formed by the carbonization of sawdust can improve the electrical conductivity and accommodate volume expansion during discharging. The porous microstructure of the shell can also provide increased active sites for the redox reactions. The in-situ-formed Fe/Fe3C nanoparticles show pseudocapacitive behavior that increases the capacity. The composite exhibits a high reversible capacity and excellent rate performance. The composite delivered a high initial discharge capacity of 1027 mAh g−1 at 45 mA g−1 and maintained a reversible capacity of 302 mAh g−1 at 200 mA g−1 after 200 cycles. Even at the high current density of 5000 mA g−1, the Fe/Fe3C@GC cell also shows a stable cycling performance. Therefore, Fe/Fe3C@GC composite is considered as one of the potential anode materials for lithium ion batteries.

A new spinel high-entropy oxide (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 with fast reaction kinetics and excellent stability as an anode material for lithium ion batteries

It is well known that transition metal oxides (TMOs) have attracted extensive attention as promising anodes for next-generation lithium ion batteries (LIBs) owing to their low cost and high theoretical capacities. However, the huge volume changes upon lithiation/delithiation cycling gradually cause drastic particle pulverization in the electrodes, thus leading to fast capacity fading and limiting their practical applications. High-entropy oxides with enhanced electronic conductivity and multiple electrochemically active elements display stepwise lithium storage behaviors, thus efficiently alleviating the volume change induced electrode pulverization problem. Herein, we report the synthesis of a new kind of spinel (Mg_0.2Ti_0.2Zn_0.2Cu_0.2Fe_0.2)₃O₄ material via a facile one-step solid state reaction method and subsequent high-energy ball-milling. When used as anodes for LIBs, the submicrometer-sized (Mg_0.2Ti_0.2Zn_0.2Cu_0.2Fe_0.2)₃O₄ particles exhibit superior lithium storage properties, delivering a large reversible capacity of 504 mA h g⁻¹ at a current density of 100 mA g⁻¹ after 300 cycles, and notably an exceptional rate capacity of 272 mA h g⁻¹ at 2000 mA g⁻¹. Our work highlights that rational design of high-entropy oxides with different electrochemically active elements and novel structures might be a useful strategy for exploring high-performance LIB anode materials in next-generation energy storage devices.

Here we present novel (Mg_0.2Ti_0.2Zn_0.2Cu_0.2Fe_0.2)₃O₄ materials prepared via one-step solid state reaction method and subsequently high-energy ball-milling. When used as anodes for LIBs, it exhibits superior lithium storage properties.

Target construction of Co3O4 with an improved layer structure for highly efficient Li-storage properties

An improved layered structure for the conversion-reaction-based anode material of Co₃O₄ is demonstrated, which displays highly efficient Li-storage properties.

High capacity MoO3/rGO nanocomposite anode for lithium ion batteries: an intuition into the conversion mechanism of MoO3

rGO wrapped MoO₃ NPs were successfully synthesized via simple and scalable steps as potential anode materials for Li-ion batteries.

K-ion and Na-ion storage performances of Co3O4-Fe2O3 nanoparticle-decorated super P carbon black prepared by a ball milling process

The hybridisation of Co₃O₄ and Fe₂O₃ nanoparticles dispersed in a super P carbon matrix is proposed as a favourable approach to improve the electrochemical performance (reversible capacity, cycling stability and rate capability) of the metal oxide electrodes in metal-ion batteries. Hybrid Co₃O₄-Fe₂O₃/C is prepared by a simple, cheap and easily scalable molten salt method combined with ball-milling and used in sodium-ion and potassium-ion batteries for the first time. The electrode exhibits excellent cycling stability and superior rate capability in sodium-ion cells with a capacity recovery of 440 mA h g^-1 (93% retention) after 180 long-term cycles at 50-1000 mA g^-1 and back to 50 mA g^-1. In contrast, Co₃O₄-Fe₂O₃, Co₃O₄ and Fe₂O₃ electrodes display unsatisfactory electrochemical performance. The hybrid Co₃O₄-Fe₂O₃/C is also reactive with potassium and capable of delivering a reversible capacity of 220 mA h g^-1 at 50 mA g^-1 which is comparable with the most reported anode materials for potassium-ion batteries. The obtained results broaden the range of transition metal oxide-based hybrids as potential anodes for K-ion and Na-ion batteries, and suggest that further studies of these materials with potassium and sodium are worthwhile.

Preparation of Advanced CuO Nanowires/Functionalized Graphene Composite Anode Material for Lithium Ion Batteries

The copper oxide (CuO) nanowires/functionalized graphene (f-graphene) composite material was successfully composed by a one-pot synthesis method. The f-graphene synthesized through the Birch reduction chemistry method was modified with functional group “–(CH₂)₅COOH”, and the CuO nanowires (NWs) were well dispersed in the f-graphene sheets. When used as anode materials in lithium-ion batteries, the composite exhibited good cyclic stability and decent specific capacity of 677 mA·h·g⁻¹ after 50 cycles. CuO NWs can enhance the lithium-ion storage of the composites while the f-graphene effectively resists the volume expansion of the CuO NWs during the galvanostatic charge/discharge cyclic process, and provide a conductive paths for charge transportation. The good electrochemical performance of the synthesized CuO/f-graphene composite suggests great potential of the composite materials for lithium-ion batteries anodes.

Highly uniform Fe3O4 nanoparticle–rGO composites as anode materials for high performance lithium-ion batteries

Ultra-small and uniform Fe₃O₄ nanoparticle–rGO composite materials have been synthesized and used as anodes for high capacity lithium-ion batteries.

P–p heterojunction CuO/CuCo2O4 nanotubes synthesized via electrospinning technology for detecting n-propanol gas at room temperature

Composite CuO/CuCo₂O₄ nanotubes were synthesized by electrospinning technology. The large specific surface area, complex tubular structure, and p–p heterojunction are the potential reasons for the excellent room temperature gas sensing performance toward n-propanol vapor.

A facile microwave-assisted approach to the synthesis of flower-like ZnCo2O4 anode materials for Li-ion batteries

A simple and rapid microwave-assisted hydrothermal (MH) method is used to synthesize spinel-based ZnCo₂O₄ anode material for Li-ion batteries.

Co2Mo3O8/reduced graphene oxide composite: synthesis, characterization, and its role as a prospective anode material in lithium ion batteries

Easy solid state synthesis of Co₂Mo₃O₈/reduced graphene oxide composite which exhibited a very high specific capacity (∼954 mA h g⁻¹) when tested as an anode material in lithium ion batteries.

Designed construction and validation of carbon-free porous MnO spheres with hybrid architecture as anodes for lithium-ion batteries

A simple, cost-effective solution mediated oxidation strategy requiring no compositing additive has been used to engineer hierarchically formed carbon-free porous MnO spheres, validated as high capacity and high rate lithium-ion battery anode.

Graphene-Protected 3D Sb-based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage

Alloy anodes have shown great potential for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene-protected 3D Sb-based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic-assembling and subsequent confinement replacement strategy. As binder-free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g(-1) at 100 mA g(-1) and 295 mAh g(-1) at 1000 mA g(-1), and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g(-1). As for sodium storage properties, the reversible capacities of 517 mAh g(-1) at 50 mA g(-1) and 315 mAh g(-1) at 1000 mA g(-1), the capacity retention of 305 mAh g(-1) after 100 cycles at 300 mA g(-1) are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high-stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder-free anodes for LIBs and SIBs.

Anatase titania synthesised at low temperature: recent breakthroughs

To overcome the limitations of conventional techniques that employ high-temperature calcinations to prepare nanosized anatase titania (TiO2), and thus find effective methods for low-temperature methods to synthesise nanosized TiO2 with high catalytic activity, has been one of the most challenging aspects in the photocatalyst field. In this article, the recent progress in low-temperature synthesis of nanosized anatase TiO2 is reviewed. The advances in this field are discussed in the light of the progress in the development of suitable synthetic methods. Particular emphasis is placed on the special conditions and demands to prepare uniform and stable anatase nanostructures at low temperature. The principles, reactions, synthesising procedures as well as the advantages and disadvantages of reported methods are presented. Furthermore, to overcome the intrinsic shortcomings of pure nanosized TiO2 as photocatalyst, that is, the rather low quantum efficiency and the incapability of utilising visible light, this review is also extended to the technologies of preparing TiO2 composites such as ion-doping, rare metal deposit and composite semiconductors. Finally the developing trends and the potential focus of future research in this field are prospected.

Facile fabrication of three-dimensional hierarchical CuO nanostructures with enhanced lithium storage capability

3D hierarchical CuO nanostructures with flower-like and urchin-like morphologies have been prepared by a solvothermal method. They display high discharge capacity, good rate capability and long cycle life as anode materials for lithium-ion battery.

Evaluation of undoped and M-doped TiO2, where M = Sn, Fe, Ni/Nb, Zr, V, and Mn, for lithium-ion battery applications prepared by the molten-salt method

Bare and Fe, Zr, Sn, Mn, V and Ni/Nb doped TiO₂ prepared by the molten salt method, amongst these the Zr-doped sample exhibited a stable reversible capacity.

Mesoporous ZnCo2O4 microspheres as an anode material for high-performance secondary lithium ion batteries

The as-prepared mesoporous ZnCo₂O₄ microspheres showed a high specific capacity and excellent electrochemical performance when used as an anode material for lithium ion batteries.

Li9V3(P2O7)3(PO4)2 nanotubes fabricated by a simple molten salt approach with excellent cycling stability and enhanced rate capability in lithium-ion batteries

Li₉V₃(P₂O₇)₃(PO₄)₂ nanotubes exhibited excellent cycling stability in addition to enhanced rate capability as cathode materials for lithium-ion batteries.

Core-shell ellipsoidal MnCo₂O₄ anode with micro-/nano-structure and concentration gradient for lithium-ion batteries

In this study, novel core-shell ellipsoidal MnCo2O4 powders with desired micro/nano-structure and a unique concentration gradient have been synthesized as anode material for Li-ion batteries. The special porous ellipsoid (2.5-4.5 μm in the long axis, 1.5-2.5 μm in the short axis, 200-300 nm in the thickness of shell) is built up by irregular nanoparticles attached to each other, and corresponding to the ellipsoid with concentration gradient, the Co/Mn atomic ratios of core and shell are about 1.76:1 and 2.34:1, respectively. The good performance, including high initial discharge capacities (1433.3 mAhg(-1) at 0.1 Ag(-1) and 1248.4 mAhg(-1) at 0.4 Ag(-1)), advanced capacity retention (∼900.0 mAhg(-1) after 60 cycles at 0.1 Ag(-1)), and fair rate performance (∼620.0 mAhg(-1) after 50 cycles at 0.4 Ag(-1)) has been measured by the battery test. Remarkably, the ellipsoidal shape and core-shell microstructure with concentration gradient are still maintained after 70 cycles of charge/discharge at 0.1 Ag(-1).

One-step calcination-free synthesis of multicomponent spinel assembled microspheres for high-performance anodes of li-ion batteries: a case study of MnCo(2)O(4)

Multicomponent spinel metal-oxide assembled mesoporous microspheres, promising anode materials for Li-ion batteries with superior electrochemical performance, are usually obtained using different kinds of precursors followed by high-temperature post-treatments. Nevertheless, high-temperature calcinations often cause primary particles to aggregate and coarsen, which may damage the assembled microsphere architectures, leading to deterioration of electrochemical performance. In this work, binary spinel metal-oxide assembled mesoporous microspheres MnCo2O4 were fabricated by one-step low-temperature solvothermal method through handily utilizing the redox reaction of nitrate and ethanol. This preparation method is calcination-free, and the resulting MnCo2O4 microspheres were surprisingly assembled by nanoparticles and nanosheets. Two kinds of MnCo2O4 crystal nucleus with different exposed facet of (1̅10) and (11̅2̅) could be responsible for the formation of particle-assembled and sheet-assembled microspheres, respectively. Profiting from the self-assembly structure with mesoporous features, MnCo2O4 microspheres delivered a high reversible capacity up to 722 mAh/g after 25 cycles at a current density of 200 mA/g and capacities up to 553 and 320 mAh/g after 200 cycles at a higher current density of 400 and 900 mA/g, respectively. Even at an extremely high current density of 2700 mA/g, the electrode still delivered a capacity of 403 mAh/g after cycling with the stepwise increase of current densities. The preparation method reported herein may provide hints for obtaining various advanced multicomponent spinel metal-oxide assembled microspheres such as CoMn2O4, ZnMn2O4, ZnCo2O4, and so on, for high-performance energy storage and conversion devices.

Maghemite nanoparticles on electrospun CNFs template as prospective lithium-ion battery anode

In this work, maghemite (γ-Fe2O3) nanoparticles were uniformly coated on carbon nanofibers (CNFs) by a hybrid synthesis procedure combining an electrospinning technique and hydrothermal method. Polyacrylonitrile nanofibers fabricated by the electrospinning technique serve as a robust support for iron oxide precursors during the hydrothermal process and successfully limit the aggregation of nanoparticles at the following carbonization step. The best materials were optimized under a carbonization condition of 600 °C for 12 h. X-ray diffraction and electron microscopy studies confirm the formation of a maghemite structure standing on the surface of CNFs. The average size of γ-Fe2O3 nanoparticles is below 100 nm, whereas CNFs are ∼150 nm in diameter. In comparison with aggregated bare iron oxide nanoparticles, the as-prepared carbon-maghemite nanofibers exhibit a higher surface area and greatly improved electrochemical performance (>830 mAh g(-1) at 50 mA g(-1) for 40 cycles and high rate capacity up to 5 A g(-1) in the voltage range of 0.005-3 V vs Li). The greatly enhanced electrochemical performance is attributed to the unique one-dimensional nanostructure and the limited aggregation of nanoparticles.

Li storage and impedance spectroscopy studies on Co3O4, CoO, and CoN for Li-ion batteries

The compounds, CoN, CoO, and Co3O4 were prepared in the form of nano-rod/particles and we investigated the Li-cycling properties, and their use as an anode material. The urea combustion method, nitridation, and carbothermal reduction methods were adopted to prepare Co3O4, CoN, and CoO, respectively. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and the Brunauer-Emmett-Teller (BET) surface and density methods were used to characterise the materials. Cyclic voltammetry (CV) was performed and galvanostatic cycling tests were also conducted up to 60-70 cycles. The observed reversible capacity of all compounds is of the increasing order CoO, Co3O4, CoN and all compounds showed negligible capacity fading. CoO allows for Li2O and Co metal to form during the discharge cycle, allowing for a high theoretical capacity of 715 mA h g(-1). Co3O4 allows for 4 Li2O and 3Co to form, and has a theoretical capacity of 890 mAhg(-1). CoN is the best anode material of the three because the nitrogen allows for Li3N and Co to form, resulting in an even higher theoretical capacity of 1100 mAhg(-1) due to the Li3N and Co metal formation. Irrespective of morphology the charge profiles of all three compounds showed a major plateaux ~2.0 V vs. Li and potential values are almost unchanged irrespective of crystal structure. Electrochemical impedance spectroscopy (EIS) was performed to understand variation resistance and capacitance values.

Molten salt synthesis of tin doped hematite nanodiscs and their enhanced electrochemical performance for Li-ion batteries

Sn⁴⁺ doped α-Fe₂O₃ nanodiscs with good lithium storage properties have been prepared by a molten salt method.