▎ 摘　　要

Lithium preintercalated bilayered vanadium oxide (LVOor & delta;-Li x V2O5 & BULL;nH(2)O) and graphene oxide (GO) nanoflakeswere assembledusing a concentrated lithium chloride solution and annealed undervacuum at 200 & DEG;C to form two-dimensional (2D) & delta;-Li x V2O5 & BULL;nH(2)O and reduced GO (rGO) heterostructures. We found thatthe Li+ ions from LiCl enhanced the oxide/carbon heterointerfaceformation and served as stabilizing ions to improve structural andelectrochemical stability. The graphitic content of the heterostructurecould be easily controlled by changing the initial GO concentrationprior to assembly. We found that increasing the GO content in ourheterostructure composition helped inhibit the electrochemical degradationof LVO during cycling and improved the rate capability of the heterostructure.A combination of scanning electron microscopy and X-ray diffractionwas used to help confirm that a 2D heterointerface formed betweenLVO and GO, and the final phase composition was determined using energy-dispersiveX-ray spectroscopy and thermogravimetric analysis. Scanning transmissionelectron microscopy and electron energy-loss spectroscopy were additionallyused to examine the heterostructures at high resolution, mapping theorientations of rGO and LVO layers and locally imaging their interlayerspacings. Further, electrochemical cycling of the cation-assembledLVO/rGO heterostructures in Li-ion cells with a non-aqueous electrolyterevealed that increasing the rGO content led to improved cycling stabilityand rate performance, despite slightly decreased charge storage capacity.The heterostructures with 0, 10, 20, and 35 wt % rGO exhibited capacitiesof 237, 216, 174, and 150 mAh g(-1), respectively.Moreover, the LVO/rGO-35 wt % and LVO/rGO-20 wt % heterostructuresretained 75% (110 mAh g(-1)) and 67% (120 mAh g(-1)) of their initial capacities after increasing thespecific current from 20 to 200 mA g(-1), while theLVO/rGO-10 wt % sample retained only 48% (107 mAh g(-1)) of its initial capacity under the same cycling conditions. In addition,the cation-assembled LVO/rGO electrodes exhibited enhanced electrochemicalstability compared to electrodes prepared through physical mixingof LVO and GO nanoflakes in the same ratios as the heterostructureelectrodes, further revealing the stabilizing effect of a 2D heterointerface.The cation-driven assembly approach, explored in this work using Li+ cations, was found to induce and stabilize the formationof stacked 2D layers of rGO and exfoliated LVO. The reported assemblymethodology can be applied for a variety of systems utilizing 2D materialswith complementary properties for applications as electrodes in energystorage devices.