Exploring the Bifunctional Electrochemical Behavior of Cu_{2 - x} Te@Reduced Graphene Oxide for Energy Storage and Water...

The development of multifunctional materials is vital for next-generation sustainable energy technologies. Here, we report a bifunctional Cu_{2 - x} Te@rGO nanocomposite synthesized via a one-pot hydrothermal method, where copper-deficient telluride (Cu_{2 - x} Te) nanoparticles are uniformly anchored on reduced graphene oxide (rGO) sheets. The composite exhibits enhanced Li-ion storage performance, delivering a capacity of 554 mAh g^-1, outperforming pristine Cu_{2 - x} Te (349 mAh g^-1), owing to the synergistic interaction between the hierarchical Cu_{2 - x} Te nanoparticles and rGO. Detailed electrochemical characterization including the galvanostatic intermittent titration technique and cyclic voltammetry is invoked to elucidate the Li-ion storage mechanism including the Li-ion diffusion coefficient and kinetics. Further, the high-power Cu_2-x Te@rGO//activated carbon Li-ion capacitor fabricated exhibits good electrochemical performances with 88% capacity retention after 10,000 cycles. Additionally, the nanocomposite shows efficient OER activity with a low overpotential of 440 mV at 100 mA cm^-2 and a Tafel slope of 86 mV dec^-1. The integration of Li-ion capacitive performance with water splitting capability highlights the potential of Cu_{2 - x} Te@rGO nanocomposites as a promising bifunctional material for advanced energy systems.