Hydrothermal synthesis of strontium sulfide/nitrogen-graphene quantum dot composites for next-generation supercapattery devices

A supercapattery merges the advantageous characteristics of batteries and supercapacitors (SCs). During this research, we synthesized strontium sulfide (SrS) using the hydrothermal method, and then we doped it with nitrogen/graphene quantum dots (N-GQDs). For SrS/NGQDs, the Brunauer-Emmett-Teller (BET) analysis determined the total surface area to be 15.50 m2 /g. Using the three-electrode assembly, the composite strontium sulfide (SrS/NGQDs) revealed a specific capacity (Cs) of 737 Cg-1. Battery-graded SrS/N-GQDs was utilized as anode and activated carbon (AC) as cathode to assemble a hybrid supercapacitor (SC). It delivered a remarkable power density of 1440 Wkg-1, the SrS/N-GQDs//AC supercapattery displayed 167 Cg-1 in terms of capacity and an energy density of 35.7 Whkg -1. SrS/N-GQDs//AC maintained 91% of its initial capacity after 5000 cycles. SrS/N-GQDs has remarkable electrochemical performance, indicating its potential use as a nanostructured electrode in next-gen electrochemical energy storage (EES) devices.