Synthesis of oxygen vacancies implanted ultrathin WO 3-x nanorods/reduced graphene oxide anode with outstanding Li-ion storage

Transition metal oxides have shown an extraordinary potential for lithium-storage capability to date. However, it remains enormous challenge to gain high capacities, good rate performance and cyclability due to their inferior conductivity. To address this issue, oxygen vacancies (VOs) implanted ultrathin WO3 nanorods (the diameter around 5 nm and the length less than 100 nm) composed with reduced graphene oxide (namely WO3-x/rGO), were synthesized by proposing a logical design. For the sake of better showing the outcome of such configuration, holy nanosheets of pure WO3 anode were proposed to compare with nanorods WO3-x/rGO one in terms of electrochemical properties, and they were obtained via annealing H2WO4/rGO precursor in air and argon atmosphere with the same annealing ramp, respectively. By contrast, both electron paramagnetic resonance and X-ray photoelectron spectroscopic characterizations demonstrate the existence of VOs in WO3-x/rGO composite. The generation of VOs together with the reserve of rGO, the conductivity of WO3-x/rGO anode is distinctly enhanced, which is then verified by the compared electrochemical performance in this work. It is clearly shown that the WO3-x/rGO nanocomposite displays a capacity of 745 mAh g−1 at a current density of 0.1 A g−1 after 200 cycles and excellent cycling stability up to 1000 cycles with capacity of 428 mAh g−1 at 1 A g−1. These findings exhibit that nanorods WO3-x/rGO nanocomposite is a promising candidate for high-performance Li-ion battery anode.