Study On Vanadate-based Nanocomposites Anode Materials And Electrochemical Performance

Lithium-ion batteries are widely favored by researchers because of their high gravimetric and volumetric energy density,high power capability,and long cycle life.With the rapid development of high-end electronic devices,current lithium-ion batteries cannot meet their requirements for energy density and safety performance.Anode materials play an important role in improving the overall performance of the battery.At present,graphite is one of the few commercial anode materials available.However,its low specific capacity and safety concern resulting from dendrite lithium growth hinder its application in the future.Therefore,finding suitable anode materials is urgent to promote the development of lithium-ion batteries in the future.Owing to their high specific capacity,low cost and rich in earth.Vanadate-based materials are expected to replace graphite as anode.Therefore,two binary vanadium-based nanocomposites have been designed in this paper.The conclusions are as follows:(1)Carbon coated Li3VO4(C@LVO)rods are prepared by a morphology route.The effects of carbon source amount on morphology and electrochemical performance are studied.C@LVO rods are furtherly analyzed by a series of material characterization and electrochemical tests.The results show that the rod morphology of C@LVO particle not only facilate Li-on transport but also withstand significant stress in charge-discharge process.Carbon coating improves conductivity of C@LVO.Thus,C@LVO rods as an anode material shows an excellent cycling stability(440 and 310 mAh g-1 after 300 cycles at 0.2 C and 5 C,respectively)and high rate capability(310 mAh g-1 at 10C).(2)Nano Ni3V2O8/C particales are prepared by oil bath and subsequently calcination.The effects of carbon source amount on Ni3V2O8 are studied.On the one hand,with the increase of PVP content,the size of nano-Ni3V2O8/C particles decreased first and then increased,and the dispersibility increased first and then decreased.When 0.1g PVP was added,the size of nano-Ni3V2O8/C particles was the smallest and the dispersion was the best.The conductivity is also improved.On the other hand,the addition of PVP makes the Ni3V2O8 nanoparticles form an interconnected structure with carbon.This structure can effectively alleviate the volume change of nano-Ni3V2O8/C nanoparticles during charge and discharge.So cycling stability of the electrode is improved.Thus its overall electrochemical performance is significantly improved.For instance,it still has a discharge capacity of 1284 mAh g-1 after 300 cycles at a current density of 300 mA g-1.