Mo-Doped SnO2 Quantum Dots Dispersed Over Reduced Graphene Oxide Sheets as an Efficient Anode Material

Abstract

Abstract We explore the effect of Mo doping over the large enhancement of electrochemical property of Mo-doped SnO2 quantum dots (3–5 nm) grown over rGO (reduced graphene oxide) sheets by a soft chemical process in ambient conditions. The composites were prepared over a range of Mo doping concentrations (0–10%) and 5% Mo doping had achieved the best energy storage characteristics. The capacity of the active material could reach ∼851 mAh g−1 (@ 78 mA g−1) in the beginning and that retained ∼89% (∼758 mAh g−1) with superior cyclic stability (100 cycles) and rate capability (506 mAh g−1 @ ∼1.5 A g−1). The addition of the reductant of 0.06 mol during the synthesis procedure led to further improvement of the capacity to ∼875 mAh g−1 (∼92% retention) and the rate capability (∼587 mAh g−1). These impressive results are ascribed to the distribution of Mo-doped SnO2 QDs, doping of Mo6+ at Sn4+ lattice sites providing more electrons for easy electrical transport, reduction of GO (graphene oxide) to rGO. Mo doping led to the decline in the charge transfer resistance (Rct) from 14.99 Ω for un-doped SnO2/rGO to 14.09 Ω (2.5%), 11.61 Ω (5%), and 11.4 Ω (10%) and promote the electrochemical property of the composite. A simple room-temperature synthesis process was used to produce Mo-doped SnO2/rGO nanocomposite and can be employed for the production of many other oxides and their composites for interesting applications.