Synthesis of RuO2 decorated quasi graphene nanosheets and their application in supercapacitors

Abstract

Multiwalled carbon nanotubes (MWCNTs) are split along the longitudinal direction to form quasi graphene oxide (QGO) by modified Hummers method and quasi graphene nanosheet/RuO₂ (QGN/RuO₂) composites with 40.0 wt% RuO₂ loading are prepared by a one-step hydrothermal synthesis without any reducing agent. The characterization of morphology and structure shows that the amorphous RuO₂ nanoparticles are uniformly dispersed on all the surfaces of QGN. The electrochemical measurements show that the QGN/RuO₂ composites exhibit good capacitive properties compared to pure RuO₂ and pure QGN in acidic, alkaline and even in neutral electrolytes. The specific capacitances of QGN/RuO₂ in 1 M KOH, 1 M H₂SO₄, and 1 M Na₂SO₄ are 453.7, 415.7, 287.5 F g⁻¹. Significantly, the QGN/RuO₂ composites can achieve a high voltage window of 1.6 V and greatly increase the energy density (102.2 W h kg⁻¹) and power density (1600 W kg⁻¹) of supercapacitors in 1 M Na₂SO₄ (1 A g⁻¹). These results demonstrate that the QGN/RuO₂ composites are a promising material for high-performance supercapacitors.