Graphene-modified nanostructured vanadium pentoxide hybrids with extraordinary electrochemical performance for Li-ion batteries

Abstract

The long-standing issues of low intrinsic electronic conductivity, slow lithium-ion diffusion and irreversible phase transitions on deep discharge prevent the high specific capacity/energy (443 mAh g À 1 and 1,550 Wh kg À 1 ) vanadium pentoxide from being used as the cathode material in practical battery applications. Here we develop a method to incorporate graphene sheets into vanadium pentoxide nanoribbons via the sol-gel process. The resulting graphene-modified nanostructured vanadium pentoxide hybrids contain only 2 wt. % graphene, yet exhibits extraordinary electrochemical performance: a specific capacity of 438 mAh g À 1 , approaching the theoretical value (443 mAh g À 1 ), a long cyclability and significantly enhanced rate capability. Such performance is the result of the combined effects of the graphene on structural stability, electronic conduction, vanadium redox reaction and lithium-ion diffusion supported by various experimental studies. This method provides a new avenue to create nanostructured metal oxide/graphene materials for advanced battery applications.

Interdependence of Structure, Morphology, and Phase Transitions in CVD Grown VO2 and V2O3 Nanostructures

“…The binary V:O phase diagram consists of several homovalent and mixed-valent oxides (V2O5, VO2, V2O3, V6O13) that exhibit distinctive electrical and optical properties interesting for various technological applications for thermochromic [1][2][3][4] , catalytic [5] , sensing [6] and electrode materials [7,8] . The rich variety of vanadium:oxygen stoichiometries emerge from the ability of vanadium atoms to adopt multiple oxidation states (+3, +4, +5), which in turn results in a synthetic challenge, when growing monophasic films of vanadium oxides.…”

Anomalous lattice behavior of vanadium pentaoxide (V2O5): X-ray diffraction, inelastic neutron scattering and ab initio lattice dynamics

“…Orthorhombic, α-V 2 O 5 is studied under high pressure by various experimental techniques like XRD 40,41,43,92,93 , neutron powder diffraction 94 , high-resolution transmission electron microscopy 94 spectroscopic 93,95 and theoretical ab-initio density functional theory 41,72,96 (DFT) [25] etc. Raman spectra and density functional calculations 72 The microscopic mechanism of phase transition from α to β phase studied using density functional theory approach 96 and structure is found to be independent of the synthesis method 92 .…”

“…Vanadium based oxides show a variety of interesting properties like catalytic behavior 14,15 , metal insulator transition [16][17][18] and super capacitor 11,19,20 properties. The low cost, high abundance, easy synthesis and high energy density 21,22 of vanadium pentaoxide (V 2 O 5 ) make it useful as a cathode material for Li and Na ion batteries 4,9,[23][24][25][26][27][28][29][30] . It also finds application in solar cells 31 as window material, antireflection coatings, critical temperature sensors 32 and light detectors.…”

Effect of Annealing Atmosphere Induced Crystallite Size Changes on the Electrochemical Properties of TiO2 Nanotubes Arrays

“…Therefore, developing novel anodes with higher capacity and superior stability has become an urgent task. Nanomaterials of metal oxides, such as Co 3 O 4 [3,4], SnO 2 [5], FeO x [6], V 2 O 5 [7] and NiO [3] have been intensively studied as anode materials for LIBs aimed at achieving higher specific capacities than graphite. For instance, nanocrystals of Co 3 O 4 have been synthesized for LIBs anodes with specific capacities ~2 times that of graphite, affording LIBs with higher energy density [3,8].…”