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• Amorphous LiV 3 O x was encapsulated into carbon nanofibers via electrospinning and subsequent annealing. • The amorphous LVO@CNFs demonstrated superior lithium storage performance compared with the crystalline LiV 3 O 8. • The amorphous structure and carbon hybridization contributed to the enhanced electrochemical properties. We design and fabricate a novel hybrid with amorphous lithium vanadate (LiV 3 O x , LVO for short) uniformly encapsulated into carbon nanofibers (denoted as LVO@CNFs) via an easy electrospinning strategy followed by proper postannealing. When examined for use as anode materials for lithium-ion batteries (LIBs), the optimized LVO@CNFs present a high discharge capacity of 603 mAh g−1 with a capacity retention as high as 90% after 200 cycles at 0.5 A g−1 and a high rate capacity of 326 mAh g−1 after 400 cycles even at a high rate of 5 A g−1. The superior electrochemical performance with excellent cycling stability and rate capability is attributed to the full encapsulation of the amorphous LVO into the conductive carbon nanofibers, which hold enlarged electrochemically active sites for lithium storage, facilitate the charge transfer, and efficiently alleviate the volume changes upon lithium insertion/extraction. More importantly, the current synthesis can be a general strategy to fabricate various alkaline earth metal vanadates, which is promising for developing advanced electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) is a promising anode for lithium‐ion batteries (LIBs) due to its long lifespan and high rate capability, arising from its excellent structural stability upon lithium intercalation‐deintercalation, but suffers from low conductivity and diffusivity. In contrast, germanium (Ge) possesses high specific theoretical capacity (1600 mA h g−1) as well as high electrical conductivity and high Li+ diffusivity, but the large volume changes upon cycling and the high price still impede its practical application. Herein, with the objective to overcome the drawbacks of TiO2‐based anode materials, Ge/TiO2@C nanotablets with a small amount of Ge content are successfully prepared by annealing C4H12GeO4/MIL‐125 mixtures in Ar/H2 atmosphere. Benefiting from the well‐dispersion of Ge nanoparticles within the TiO2@C matrices, the composites exhibit superior electrochemical performance when examined as a LIB anode material, delivering high reversible capacities of 502/258 mA h g−1 after 200/500 cycles at current densities of 200/500 mA g−1, respectively. Notably, the Ge/TiO2@C shows enhanced surface/pore features and demonstrates improved conductivity, lithium diffusion and specific capacities, owing to the introduction of Ge component. [ABSTRACT FROM AUTHOR]

Alloy-/conversion-type metal oxides usually exhibit high theoretical lithium storage capacities but suffer from the large volume change induced electrode pulverization and the poor electric conductivity, which limit their practical applications. Hybrid/mixed metal oxides with different working mechanisms/potentials can display advantageous synergistic enhancement effect if delicate structure engineering is performed. Herein, atomically hybridized SnO 2 /Co 3 O 4 nanocomposites with amorphous nature are successfully cast onto the porous N -doped carbon (denoted as NC) nanoflakes through facile pyrolysis of the tin (II) 2-ethylhexanoate (C 16 H 30 O 4 Sn) and cobalt (II) 2-ethylhexanoate (C 16 H 30 O 4 Co) mixture within NC nanoflakes in air at 300 °C for 1 h. The Sn/Co atomic ratio and the loading amount of SnO 2 /Co 3 O 4 can be readily controlled, whose effect on lithium storage are investigated as anodes for lithium ion batteries (LIBs). Notably, SnO 2 /Co 3 O 4 @NC (R Sn/Co = 1.25) nanoflakes exhibit the most excellent lithium storage properties, delivering a reversible capacity of 1450.3 mA h g−1 after 300 cycles at 200 mA g−1, which is much higher than that of the single metal oxide SnO 2 @NC and Co 3 O 4 @NC electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn 2 V 2 O 7 microspheres with solid or hollow interiors were realized via a facile solvothermal method followed by annealing. • The effects of PVP as controlling agent on the structure and electrochemical properties of Mn 2 V 2 O 7 were revealed. • Mn 2 V 2 O 7 microspheres demonstrated superior lithium storage performance owing to the favorable structure. We report the fabrication of well-defined phase-pure Mn 2 V 2 O 7 hollow microspheres (h-MVO), assembled from the porous plate-like building blocks, via a facile solvothermal method followed by annealing, with the assistance of polyvinylpyrrolidone (PVP) as the structure-regulating agent. The microstructure dependent electrochemical properties of h-MVO as anode materials for lithium ion batteries (LIBs) are investigated, and excellent lithium storage performance is obtained with a reversible capacity of 1707 mAh g−1 after 700 cycles at 0.5 A g−1, revealing that the unique hierarchical framework of the h-MVO microspheres with hollow interiors and porous building blocks could not only accelerate the transport of Li+ ions and electrolyte, but also efficiently suppress the electrode pulverization upon cycling. More importantly, we demonstrate that PVP can be an effective agent to tune the microstructures, which would be promising for the development of high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

To explore advanced anode materials with superior Li+/Na+/K+ storage performances for alkaline ion batteries (AIBs), a hybrid of amorphous vanadium oxide uniformly embedded into the highly defective carbon nanofibers (denoted as VO x @CNFs) was fabricated via a facile electrospinning method followed by proper heat treatment in this work. The integrated structure synergistically combines the advantages of the amorphous VO x and the defective carbon matrices, which can not only bring abundant active sites for ion storage and multi-channels for ion diffusion, but also well accommodate the structural change induced electrode pulverization. When evaluated as anode materials for AIBs, the optimized VO x @CNFs demonstrate excellent alkaline ion storage performances with high-specific capacities, long-cycling life and high-rate capabilities, delivering a Na+ storage capacity of 260 mAh g−1 at 1.0 A g−1 after 1000 cycles, a Li+ storage capacity of 556 mAh g−1 at 0.5 A g−1after 500 cycles, and a K+ storage capacity of 198 mAh g−1 at 0.5 A g−1 after 400 cycles. Image, graphical abstract [ABSTRACT FROM AUTHOR]