Facile synthesis of NiTe₂-Co₂Te₂@rGO nanocomposite for high-performance hybrid supercapacitor

The design of bimetallic tellurides that exhibit excellent electrochemical properties remains a huge challenge for high-performance supercapacitors. In the present study, tellurium is consolidated on CoNi₂@rGO for the first time, to synthesize NiTe₂-Co₂Te₂@rGO nanocomposite by using a facile hydrothermal method. As-prepared NiTe₂-Co₂Te₂@rGO nanocomposite was characterized by EDS, TEM, FESEM, Raman, BET, XRD, and XPS techniques to prove the structural transformation. Upon the electrochemical characterization, NiTe₂-Co₂Te₂@rGO has notably presented numerous active sites and enhanced contact sites with the electrolyte solution during the faradic reaction. The as-prepared nanocomposite reveals a specific capacity of 223.6 mAh g^-1 in 1.0 M KOH at 1.0 A g^-1. Besides, it could retain 89.3% stability after 3000 consecutive galvanostatic charge-discharge cycles at 1.0 A g^-1 current density. The hybrid supercapacitor, fabricated by activated carbon as an anode site, and NiTe₂-Co₂Te₂@rGO as a cathode site, presents a potential window of 1.60 V with an energy density of 51 Wh kg^-1 and a power density of 800 W kg^-1; this electrode is capable of lighting up two red LED lamps and a yellow LED lamp for 20 min, which is connected in parallel. The present work opens new avenues to design and fabrication of nanocomposite electrode materials in the field of supercapacitors.