Facile in situ synthesis of Ag and MnO2 anchored on carbon microtubes for high-performance asymmetric supercapacitor applications

Abstract A novel structure of carbon hollow microtubes decorated with Ag nanoparticles and amorphous MnO2 was rationally designed and fabricated by a one-step route for the first time. The Kirkendall effect is involved between KMnO4 and Ag/C coaxial microwire templates under a solvothermal environment. The composites show an excellent electrochemical performance in supercapacitor and the capacity can reach up to 301 F g−1 in a three-electrode system. When assembled as an aqueous hybrid supercapacitor device with the C/Ag/MnO2 hybrids and activated carbon as the positive and negative electrodes, respectively, the device exhibits a high-energy density of 16.6 W h kg−1 at a power density of 1920 W kg−1, as well as good cycling stability of 130% capacity retention after 5000 cycles. This can be ascribed to the Ag nanoparticles have excellent conductivity and MnO2 can highly increase the capacity of the supercapacitor. The present work provides an excellent scheme for high-performance asymmetric supercapacitor applications.