Laser writing of graphene-tin hybrid composite-based supercapacitor for battery-like performance

Supercapacitor (SC) with a wide operation voltage window in an aqueous electrolyte is a critical key for boosting energy, overcoming safety and fabrication cost obstacles. Thus, tin dioxide/graphene (SGO) was synthesized using one-pot method for easy and hybrid metal oxide decoration on graphene sheet. Laser writing (LW) technique was employed to enhance SGO active material's electrochemical performance through high-power laser irradiation of two different optical ranges 355 and 1046 nm. Photothermal laser processing achieved ternary Sn-SnO2-RGO composition of specific capacitance to similar to 872 and 385 F/g at 5 mV/s and 1 A/g, respectively. Nanosecond laser pulses induced extensive SGO exfoliation and redistribution of reduced tin metal on graphene sheets' edges. Laser-processed SGO SCs offer a battery-like energy density of 173 Wh/Kg at 1 A/g coupled with high power of 283 kW/Kg at 80 A/g. Interestingly, the retention at a high current of 80 A/g is nearly >99.6 %, which suggests a strong coupling between tin metal/tin dioxide and graphene 3D conductive networking. LW impact on capacitive performance was deliberately guarded by photothermal and photochemical interactions. SGO-based SCs binder-free electrodes were conducted to Raman spectroscopy, X-ray diffraction, different electron imaging, elemental analysis and extensive electrochemical characterization.