Graphene and cobalt phosphide nanowire composite as an anode material for high performance lithium-ion batteries

The synthesis of a composite of cobalt phosphide nanowires and reduced graphene oxide (denoted CoP/RGO) via a facile hydrothermal method combined with a subsequent annealing step is reported. The resulting composite presents large specific surface area and enhanced conductivity, which can effectively facilitate charge transport and accommodates variations in volume during the lithiation/de-lithiation processes. As a result, the CoP/RGO nanocomposite manifests a high reversible specific capacity of 960 mA·h·g^–1 over 200 cycles at a current density of 0.2 A·g^–1 (297 mA·h·g^–1 over 10,000 cycles at a current density of 20 A·g^–1) and excellent rate capability (424 mA·h·g^–1 at a current density of 10 A·g^–1).

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Layered K0.54Mn0.78Mg0.22O2 as a high-performance cathode material for potassium-ion batteries

Layered Mn-based oxides are one of the promising cathode materials for potassium-ion batteries(KIBs)owing to their high theoretical capacities,abundant material...     

Interconnected MoO2 nanocrystals with carbon nanocoating as high-capacity anode materials for lithium-ion batteries

A facile one-pot hydrothermal method has been developed for the preparation of carbon-coated MoO(2) nanocrystals. The annealed MoO(2)-C nanocomposite consists of interconnected MoO(2)@C nanocrystals. When evaluated for lithium storage capabilities, these MoO(2)@C nanocrystals exhibit high specific capacities (~640 mA h g(-1) at 200 mA g(-1) and ~575 mA h g(-1) at 400 mA g(-1)) and excellent cycling stability. In view of the excellent lithium storage properties and the ease in large-scale preparation, the as-synthesized MoO(2)-C nanocomposite might be used as promising anode materials for high-performance lithium-ion batteries.     

Nb2O5 hollow nanospheres as anode material for enhanced performance in lithium ion batteries

Nb₂O₅ hollow nanospheres of average diameter ca. ～29 nm and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb₂O₅ hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g^?1 after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g^?1. The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb₂O₅ shell domain that facilitates fast lithium intercalation/deintercalation kinetics.     

Recent advances in anode materials for potassium-ion batteries: A review

Potassium-ion batteries (PIBs) are appealing alternatives to conventional lithium-ion batteries (LIBs) because of their wide potential window, fast ionic conductivity in the electrolyte, and reduced cost. However, PIBs suffer from sluggish K⁺ reaction kinetics in electrode materials, large volume expansion of electroactive materials, and the unstable solid electrolyte interphase. Various strategies, especially in terms of electrode design, have been proposed to address these issues. In this review, the recent progress on advanced anode materials of PIBs is systematically discussed, ranging from the design principles, and nanoscale fabrication and engineering to the structure-performance relationship. Finally, the remaining limitations, potential solutions, and possible research directions for the development of PIBs towards practical applications are presented. This review will provide new insights into the lab development and real-world applications of PIBs.

     

Nanoarchitectonics on Bi2MoO6 by alkali etching for enhanced photocatalytic performance

As a layered photocatalyst, the photogenerated carriers separation efficiency of bismuth molybdate (Bi₂MoO₆) can be improved by introduction of oxygen vacancy. The alkali etching method provides a facile structural tuning way for modifying the bismuth-based semiconductors. Defect state bismuth molybdate (Bi₂MoO₆) photocatalyst was synthesized by alkali etching. The structure of Bi₂MoO₆ was tuned by adjusting the concentration of alkali solution. The phase structure, morphology, surface chemistry, and optical property of Bi₂MoO₆ were characterized by kinds of characterization methods such as X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance absorption spectroscopy. The phase of Bi₂MoO₆ can be transformed to Bi₂O₃ accompanied with the change of morphology due to the etching of molybdenum atom and oxygen atom from the Bi₂MoO₆ body structure by sodium hydroxide solution. Meanwhile, the concentration of oxygen vacancy increased obviously as indicated by the XPS results. Therefore, the separation efficiency of photogenerated carriers was enhanced because of the promotion of oxygen vacancy. Alkali etching Bi₂MoO₆ by 0.075 M sodium hydroxide solution exhibited an excellent photocatalytic performance owing to the suitable vacancy concentration. Superoxide free radicals instead of hydroxyl radicals took the important role in the photodegradation process.     

Amphiphilic carbonaceous material modified graphite as anode material for lithium-ion batteries

Artificial graphite powder was coated by amphiphilic carbonaceous material (ACM) in aqueous solutions. SEM and XRD results show that the surface defects and edge sites of original graphite are uniformly covered by the ACM coating layer after modification. The overall characteristics of graphite, however, are not severely changed. Electrochemical measurements were then carried out to evaluate the anode performances of samples in lithium-ion batteries. The modified graphite shows an initial efficiency up to 90.6% and discharge capacitance of 366.4 mAhg^− 1. Meanwhile, its capacitance remains as high as 350 mAhg^− 1 after 30 cycles charge/discharge tests, evincing good cyclic performance. Compared with conventional methods, the abovementioned non-organic solvent coating presents an economic, facile, and green pathway for graphite mass utilisation as an alternative anode material in lithium-ion batteries.     

Two-dimensional metallic BP as anode material for lithium-ion and sodium-ion batteries with unprecedented performance

Improving the storage capacities of electrode materials is one of the most critical points for ion batteries. Two-dimensional (2D) topological semimetals with high carrier mobility are naturally suitable as electrode materials. Herein, using the first-principle calculations, 2D BP monolayer with Dirac-type band structure is predicted to be a superior anode material with ultrahigh capacity for both Li/Na-ion batteries. The BP monolayer remains metallic after the adsorption of Li/Na ions, ensuring a good conductivity. Furthermore, BP owns low diffusion barriers (0.35 eV for Li ions and 0.16 eV for Na ions) and a moderate lattice change (3%) during the process of charging and discharging. Remarkably, the storage capacity of monolayer BP is enhanced to 1924 mAh/g by multilayer adsorption of both Li/Na ions, much higher than those of most previous 2D anode materials. All these characteristics strongly suggest that BP has great potential as a superior anode material in Li/Na-ion batteries.

     

MnO nanorods on graphene as an anode material for high capacity lithium ion batteries

The MnO/graphene hybrid nanocomposites were prepared by an in situ reduction method. The MnO₂ nanorods were attached on the graphene oxides (GOs) to form the MnO₂/GO nanocomposites, which were reduced to the MnO/graphene hybrid under argon atmosphere. As the anode material for the lithium ion batteries, the MnO/graphene electrodes delivered a high initial charge capacity up to 747 mAh g^?1 and a stable capacity of 705.8 mAh g^?1 after 100 cycles, which is much superior to pure MnO with initial charge capacity of 456 mAh g^?1 and the stable capacity of 95.6 mAh g^?1 after 100 cycles. The scanning electron microscope images of the MnO/graphene hybrid nanocomposites after cycling demonstrated that the graphene could prevent the MnO from aggregating during the charge/discharge process.     

Structure and electrochemical performance of ZnO/CNT composite as anode material for lithium-ion batteries

Metal oxides are well-known potential alternatives to graphite as anode materials of lithium-ion batteries, and they can deliver much higher reversible capacities than graphite even at high current densities. In this study, hexagonal disk-shaped ZnO are synthesized by a facile solution reaction of ZnCl₂ and its composite is prepared in the presence of carbon nanotubes (CNTs). The as prepared ZnO/CNT composite has been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fourier transform-infrared spectroscopy and Rutherford backscattering spectroscopy. Electrochemical characterization by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/charge tests demonstrate that the conversion reactions in ZnO and ZnO/CNT electrodes enable reversible capacity of 478 and 602 mAh g^?1, respectively for up to 50 cycles. Our investigation highlights the importance of anchoring of small ZnO particles on CNTs for maximum utilization of electrochemically active ZnO and CNTs for energy storage application in lithium-ion batteries.     

Cathodic titania nanotube arrays as anode material for lithium-ion batteries

The titanium dioxide nanotube arrays (TNAs) have been synthesized at cathode and anode via standard electrochemical method for their subsequent use as anode material for lithium-ion batteries (LIBs). The TNAs fabricated at cathode have higher Ti³⁺ in comparison to TNAs at anode, which was confirmed using X-ray photoelectron spectroscopy and Raman spectrometry. Moreover, the lattice parameters of cathodic TNAs are estimated via Rietveld refinement of X-ray diffraction, which also conform to Ti³⁺ doping and insertion of protons (H⁺). The electrochemical impedance spectroscopy hints an increment in the electronic conductivity of TNAs fabricated at cathode. As a result, high reversible areal–specific capacity (~385.5 µAh cm^?2 at 100 µA cm^?2) with excellent rate capability is acquired by utilizing TNAs fabricated at cathode as anode material in LIBs.     

Highly transparent Bi2MoO6- and Bi2WO6-polymer nanocomposites

A combined method of precipitation, phase transfer into organic solvent, solvothermal treatment and subsequent in situ polymerization was used to integrate nanocrystalline Bi2MoO6- and Bi2WO6-particles into a polymer matrix of poly-laurylacrylate. The presented method offers a new and gentle way to produce highly transparent bulk nanocomposites containing evenly distributed Bi2MoO6- and Bi2WO6-nanoparticles. Characterization results of DLS-, XRD-, REM- and TEM-measurements are presented as well as solid state UV/VIS-measurements of the particles. The transparent nanocomposites were characterized using UV/VIS-spectroscopy and ellipsometry. All composites show a good transmission in the range from 800-400 nm. The particle content of the nanocomposites was measured with TG-measurements.     

Mesoporous SnO2 synthesized with non-ionic surfactants as an anode material for lithium batteries

Mesoporous tin oxides were successfully prepared with the use of non-ionic surfactants, Pluronic 123 (P-123) and Tetronic 908 (T-908). Surface analysis of SnO2 synthesized with P123 showed an average pore size of approximately 15 nm. The high-resolution transmission electron microscopy and low-angle X-ray diffraction (XRD) measurements also confirmed their mesoporous nature. The X-ray photoelectron spectroscopy and wide-angle XRD studies revealed that these compounds have a casserite-type SnO2 structure. The electrochemical properties of these materials as anodes in lithium batteries showed excellent performance with good reversibility. The first-cycle reversible capacity was 1026 mAh/g for the material synthesized with P123. There was a high first-cycle irreversible capacity for SnO2 synthesized with the use of both non-ionic surfactants. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to study the electrode kinetics during the lithium insertion process in the first cycle. There was a decrease in the charge-transfer resistance with respect to the discharge potential. The synthesis and structural and electrochemical properties of the mesoporous tin oxides are correlated and discussed in detail.     

Dandelion-Like Bi2S3/rGO hierarchical microspheres as high-performance anodes for potassium-ion and half/full sodium-ion batteries

Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) have been considered as attractive alternatives for next-generation battery systems, which have promising application potential due to their earth abundance of potassium and sodium, high capacity and suitable working potential, however, the design and application of bi-functional high-performance anode still remain a great challenge up to date. Bismuth sulfide is suitable as anode owing to its unique laminar structure with relatively large interlayer distance to accommodate larger radius ions, high theoretical capacity and high volumetric capacity etc. In this study, dandelion-like Bi₂S₃/rGO hierarchical microspheres as anode material for PIBs displayed reversible capacity, and 206.91 mAh·g⁻¹ could be remained after 1,200 cycles at a current density of 100 mA·g⁻¹. When applied as anode materials for SIBs, 300 mAh·g⁻¹ could be retained after 300 cycles at 2 A·g⁻¹ and its initial Coulombic efficiency is as high as 97.43%. Even at high current density of 10 A·g⁻¹, 120.3 mAh·g⁻¹ could be preserved after 3,400 cycles. The Na₃V₂(PO₄)₃@rGO//Bi₂S₃/rGO sodium ion full cells were successfully assembled which displays stable performance after 60 cycles at 100 mA·g⁻¹. The above results demonstrate that Bi₂S₃/rGO has application potential as high performance bi-functional anode for PIBs and SIBs.

     

Integrated design of sandwich-like C@MoS2@C nanospheres as active anode material for lithium-ion batteries

Journal of Materials Science - Molybdenum disulfide (MoS2) is gaining popularity as an active material for constructing anode in rechargeable lithium-ion batteries. However, the low conductivity,...     

P25/graphene nanocomposites as a high-performance anode material for lithium ion batteries

P25/graphene nanocomposites were successful synthesized in a water-ethanol solvent under hydrothermal conditions. During the process of the reduction of GO into graphene (GR), the P25 nanoparticles were decorated on graphene sheets simultaneously. Moreover, the GR content in the as-synthesized nanocomposites can be easily adjusted by changing the dosage of P25. The interesting P25/GR nanocomposites were found to be a promising anode material for lithium-ion batteries and showed significantly enhanced Li-ion insertion/extraction performance. The optimal weight percentage of GR was found to be 29.9%, which resulted in a high capacity of 282.8 mAh g⁻¹ after 50 cycles at a current rate of 0.5 C. The improved capacity may be attributed to the synergetic effect between graphene sheets and P25 nanoparticles.