VS₄ Nanoparticles Anchored on Graphene Sheets as a High‐Rate and Stable Electrode Material for Sodium Ion Batteries

Abstract

The size and conductivity of the electrode materials play a significant role in the kinetics of sodium-ion batteries. Various characterizations reveal that size-controllable VS nanoparticles can be successfully anchored on the surface of graphene sheets (GSs) by a simple cationic-surfactant-assisted hydrothermal method. When used as an electrode material for sodium-ion batteries, these VS @GS nanocomposites show large specific capacity (349.1 mAh g after 100 cycles), excellent long-term stability (84 % capacity retention after 1200 cycles), and high rate capability (188.1 mAh g at 4000 mA g ). A large proportion of the capacity was contributed by capacitive processes. This remarkable electrochemical performance was attributed to synergistic interactions between nanosized VS particles and a highly conductive graphene network, which provided short diffusion pathways for Na ions and large contact areas between the electrolyte and electrode, resulting in considerably improved electrochemical kinetic properties.

Enhanced Kinetics over VS4 Microspheres with Multidimensional Na+ Transfer Channels for High‐Rate Na‐Ion Battery Anodes

“…The stable capacity after a number of cycles indicates that the as‐expanded structure can sustain to some extent. The similar phenomena about the capacity increase and lattice extension also appear in other transition metal sulfide and oxide anode materials …”

“…In the past few years, VS 4 has been successfully appliedt o lithium-ion batteries, [10,16,17] SIBs, [8,[18][19][20] magnesium-ion batteries, [14] aluminum-ionb atteries, [21] and supercapacitors, [13,22] and its electrochemical performances as an anode material has been explored. However,p oorly defined bulk VS 4 undergoes severe pulverization and sluggish kineticsi nduced by the anisotropy in diffusion and the insufficient electrode-electrolyte contact,w hich lead to the poor cycling stabilitya nd rate capability.…”

“…However,p oorly defined bulk VS 4 undergoes severe pulverization and sluggish kineticsi nduced by the anisotropy in diffusion and the insufficient electrode-electrolyte contact,w hich lead to the poor cycling stabilitya nd rate capability. [14,23,24] Twoc ommon strategies for improving the electrochemicalp erformancesa re combining VS 4 with carbon nanomaterials [8,[18][19][20]25] and developing 3D self-assembled VS 4 nanoarchitectures. [7,14,15] Although the introductiono fc arbon nanomaterials can alleviate pulverization and promote electrochemical kinetics to some extent, the large surface area and volume increasethe side reactions and lower the energy density.…”

VS4‐Decorated Carbon Nanotubes for Lithium Storage with Pseudocapacitance Contribution

“…Two overwhelming peaks at binding energies (BEs) of 517.5 and 524.9 eV are assigned to the V 2p 3/2 and V 2p 1/2 levels of V 4+ , showing that V 4+ species are the predominant component . Two peaks centered at BEs of 516.2 and 523.9 eV are attributed to V 3+ species, which arise from the partial reduction of vanadium and are common in hydrothermally synthesized VS 4 . Interestingly, two peaks at 513.9 and 522.3 eV are observed at the V 2p 3/2 and V 2p 1/2 regions, respectively, indicating the formation of V−C bonds .…”

“…Two peaks centered at BEs of 516.2 and 523.9 eV are attributed to V 3+ species, which arise from the partial reduction of vanadium and are common in hydrothermally synthesized VS 4 . Interestingly, two peaks at 513.9 and 522.3 eV are observed at the V 2p 3/2 and V 2p 1/2 regions, respectively, indicating the formation of V−C bonds . The S 2p XPS region (Figure c) consists of three deconvoluted peaks.…”