Template-free synthesis of porous V2O5 yolk-shell microspheres as cathode materials for lithium ion batteries

The porous V2O5 yolk-shell microspheres have been synthesized via hydro/solvothermal method with subsequent annealing treatment. Due to the volume contraction of the solid microspheres prepared by hydro/solvothermal reaction and the decomposition and combustion of the organics in air, the porous yolk-shell microspheres were prepared. Derived from the unique structure, the porous V2O5 yolk-shell microspheres show a better electrochemical performance than the pristine V2O5 powder. The electrochemical performance of yolk-shell microspheres is tested between 2.0 and 4.0 V, the V2O5 microspheres can deliver a high initial capacity of 287.2 mA h g(1), and a good capacity of 225.7 mA h(-1) can be reached at a current density of 50 mA g(-1) after 50 cycles. Moreover, the microspheres electrode possess a higher capacity than the pristine V2O5 powder under the same rate, for example, 159.5 mA h g(-1) of V2O5 yolkshell microspheres vs. 144.6 mA h g(1) of pristine V2O5 powder at a current density of 2000 mA g(-1). Even at 1000 mA g(-1) in the voltage range of 2.5-4.0 V, the yolk-shell microspheres can also deliver a good discharge capacity of 117.5 mA h g(-1) after 1000 cycles. (C) 2017 Elsevier B.V. All rights reserved.