Journal of Materials Science, Vol.55, No.13, 5522-5533, 2020
Hierarchical porous LixV2O4/C anode assembled with nanoflake for high-performance lithium-ion battery
Vanadium-based oxides are considered to be a type of promising electrode materials for Li-ion batteries due to their low cost and high theoretical capacity. However, the dissolution of vanadium (V3+), low electron conductivity and volume change during charge and discharge processes hamper their application. A novel porous structure was synthesized by hydrothermal method in this study. The hierarchical porous structure is assembled with nanoflake and coated with carbon. The hierarchical porous structure provides multitudinous reaction sites, shortens the Li-ion transfer distance and buffers the volume variety. The carbon improves the conductivity of the composite. It is also found that the tetravalent and trivalence vanadium coexists in the prepared composite. V4+ can prevent V3+ from dissolution. The synergistic effects of hierarchical porous structure, carbon coating and the coexistence of V3+ and V4+ endow the composite with excellent performance as an anode material. The composite exhibits a low resistance and sizeable capacitive effects during the charge and discharge process, which are beneficial to the energy storage performance. A discharge capacity of 439.6 mAh g(-1) after 100 cycles at a current density of 0.1 A g(-1) is delivered, which is 90.0% of its initial specific capacity (488.2 mAh g(-1)). The composite processes a decent prospect in high-performance Li-ion batteries.