Nickel and nitrogen co-doped tin dioxide nano-composite as a potential anode material for lithium-ion batteries

Abstract

As a promising high capacity anode material for lithium-ion batteries (LIBs), tin dioxide (SnO2) has attracted considerable interest in recent studies. In this paper, nickel-doped tin dioxide (Ni/SnO2), nickel and nitrogen co-doped tin dioxide (Ni-N/SnO2) are prepared to modify the electrochemical properties of as-prepared SnO2. Samples of pure SnO2, Ni/SnO2 and Ni-N/SnO2 are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDAX), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). It is found that doping and co-doping process does not affect the phase structure of pristine SnO2. However, it obviously influences the morphology, specific surface area, and electrochemical properties of SnO2. Gavalnostatic cycling indicates that the Ni-N/SnO2 nano-composite still remains a high charge capacity of 631 mAh g−1 after 50 cycles. Rate performance evaluation shows that a capacity of 621 mAh g−1 can still be delivered when the current returns back to 0.1C after 50 cycles at different current densities. Cyclic voltammetry (CV) analysis proves that Ni and N co-doping accelerates the electrode reaction. The results of electrochemical impedance spectroscopy (EIS) demonstrate the low charge-transfer resistance for Ni-N/SnO2, and the following quantitative calculation further confirms the highest electric conductivity and ionic conductivity of Ni-N/SnO2 compared with those of pure SnO2 and Ni/SnO2. This explains the superior capacity retention and rate performance of co-doped material.