Facile synthesis of MnCO3 nanoparticles by supercritical CO2 and their conversion to manganese oxide for supercapacitor electrode materials

Abstract

Spherical manganese carbonate (MnCO 3 ) nanoparticles were prepared from manganese acetate by means of supercritical carbon dioxide (scCO 2 ). The variation of morphology according to temperature, pressure, and solvent composition was studied. Quite uniformly sized MnCO 3 nanoparticles were effectively produced in a short period of time with the aid of supercritical fluid. Furthermore, porous manganese oxide (MnO x ) nanoparticles with high surface area were obtained via calcination process of MnCO 3 nanoparticles, and its performance as a supercapacitor was investigated. The porous manganese oxide nanoparticles showed a high specific capacitance of 322 Fg -1 at 1 Ag -1 with excellent rate capability and cyclic stability. This study provides a new approach for the facile and eco-friendly fabrication of MnCO 3 nanoparticles using scCO 2 and their conversion to porous MnO x for supercapacitor application.

Fabrication of g-C3N4 Quantum Dots/MnCO3 Nanocomposite on Carbon Cloth for Flexible Supercapacitor Electrode

“…The XPS survey scans in Figure 3a show that both q-MC//CC and MC//CC samples contain the Mn, O, and C atoms, while the N peak is only found in the q-MC//CC nanocomposites due to CNQDs. The deconvolution of the Mn 2p spectrum of q-MC//CC (Figure 3b) displays two peaks located at 655.8 eV and 643.8 eV respectively, assigning to Mn 2p 1/2 and Mn 2p 3/2 with an energy separation of 12.0 eV, which coincides with Mn 2+ [18,19]. In the high-resolution C1s spectrum of q-MC//CC (Figure 3c) and MC//CC (Figure S3), two typical peaks of the C-C bond at 284.6 eV and C=O bond at 288.5 eV are observed, relating to the surface carbon of the carbon cloth and carbon element in carbonate ions [20].…”