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.

Automated summary

In this study, NiTe2-Co2Te2@rGO nanocomposite was synthesized for the first time by consolidating tellurium on CoNi2@rGO using a facile hydrothermal method. The as-prepared nanocomposite exhibited numerous active sites and enhanced contact sites with the electrolyte solution, resulting in a high specific capacity and excellent stability for supercapacitors.