Enhancing aqueous aluminum ion batteries performance by tin oxide quantum dots/graphene cathode material

In this study, the synergistic effect of tin oxide quantum dots (SnO2QDs) and reduced graphene oxide (RGO or graphene) on the performance of aqueous aluminum ion batteries (AAIBs) is investigated. The RGO/SnO2QDs composite is prepared using the rapid microwave synthesis method. The cathode is characterized using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, high-resolution transmission electron microscopy, and porosity analysis. The synthesized composite, graphene oxide (GO), and RGO are each separately coated onto a graphite sheet, and their electrochemical activity is investigated using various electrochemical methods. The battery made with the RGO/SnO2QDs composite shows capacities of 750, 203, and 193 mAh g−1 after 1, 50, and 100 consecutive charge and discharge cycles, respectively, at a current density of 400 mA g−1. The rate performance of this battery after applying different current densities is excellent, and the cycling stability of the battery after about 5620 consecutive charge and discharge cycles at a current density of 1500 mA g−1 is very good. The battery capacity only dropped by 6% compared to after 100 cycles and reached about 79 mAh g−1, while the Coulombic coefficient is reported to be 98% for the initial cycles and 95% for the final cycles.