Peapod-like V2O3 nanorods encapsulated into carbon as binder-free and flexible electrodes in lithium-ion batteries

Designing and fabricating electrodes with excellent mechanical flexibility and superior electrothemical performance for high-performance lithium ion battery (LIBs) is challenging. Herein, ultralong peapod-like nanowires (NWs) composed of short vanadium sesquioxide nanorods (V2O3 NRs) encapsulated with carbon are produced as high-performance anode materials. The freestanding and flexible film has a high capacity of 210 mAh g(-1) at a current density of 0.1 C, and exhibits appreciable rate capability with 68% capacitance retention when the current density is increased from 0.1 to 1 C, and excellent long-term cycling stability without apparent capacity fading after 125 cycles, which is better then that of the active carbon mixed V2O3 NRs and bare V2O3 NRs. The outstanding electrochemical performance is attributed to proper accommodation of the volume expansion of the vanadium oxide in the carbon in the lithiation/delithiation process as well as the outer conductive three-dimensional (3D) carbon network. The formation mechanism of the peapod-like structure is investigated by thermogravimetric analysis connected to a mass spectrometer (MS). The ultralong peapod-like nanostructure overcomes the physical and chemical drawbacks of vanadium oxide and has large potential applicability for flexible energy-storage devices. (C) 2016 Elsevier B.V. All rights reserved.