Tuning the interface interaction between Nb2O5 nanosheets/graphene for high current rate and long cyclic lithium-ion batteries

Abstract

Interface interaction as well as defect-rich nanostructures offer unique opportunity for the fabrication of high-rate performance lithium-ion batteries (LIBs). In this work, adefective multiphase Nb2O5-R nanosheets which has interface interaction with graphene oxide (GO) was synthesized. The intensity of interface interaction was tuned by controlling the stoichiometric ratio (Nb2O5-R/GO x where x = 1, 5, 10). It is found that Nb2O5-R/GO5 electrode exhibits highest reversible capacity at 1 C, 2 C, 5 C, 10 C, 25 C and 35 C, slow capacity retention and a stable columbic efficiency of 93.4%. The electrode demonstrates a reversible capacity of 292.0 mAhg−1 at 1 C after 70 cycles with a capacity retention rate of 89.9% and 220 mAhg−1 is still retained at the rate of 5 C after 800 cycles, which proves its superior cyclic stability. Moreover, the electrochemical impedance spectroscopy (EIS) also confirms the improved kinetics of Nb2O5-R/GO5 electrode. The appropriate oxygen vacancies and GO contents, as well as strong interface interaction between Nb2O5-R and GO leads to increase in conductivity, structural stability and provide extra active sites for rapid lithium storage.The results provide a new strategy for the development of new anode materials for LIBs with high-rate capability and long cycle life.