Synthesis of organic hybrid ruthenium oxide nanoparticles for high-performance supercapacitors

Abstract

Ruthenium oxide has long been considered as an excellent pseudocapacitive electrode material with high specific capacitance and high energy density, but suffers from poor electrochemical stability. In this work, the capacitive performance and electrochemical stability of RuO2 are significantly enhanced by applying hybrid RuO2 materials, which are prepared by precipitation reaction using RuCl3 in the presence of polyhydroxy organic molecules. RuO2 wrapped by sorbitol and tween is defined as RuO2@S+T, and by glucose and tween is defined as RuO2@G+T. It is shown that the specific capacitances of RuO2@S+T and RuO2@G+T at 1 A g−1 are 1865.7 and 1792.0 F g−1, much larger than the 602.6 F g−1 of pristine RuO2. The improvement in electrochemical stability is also evident, with the capacitance retention of 93.9% and 90.2% for RuO2@S+T and RuO2@G+T, respectively, after 8000 charging-discharging cycles, which is much more stable than the 30.2% for pristine RuO2. This improvement can be attributed to the small size and uniform distribution of RuO2@S+T and RuO2@G+T nanoparticles that facilitate proton and electron transfer, as well as the surrounding organic molecules that can stabilize RuO2 structure and also facilitate proton transfer. The hybrid RuO2 material used in this work could be extended to design and invent stable electrode materials for high-performance supercapacitors.