Synthesis of nanosized MnO2 prepared by the polyol method and its application in high power supercapacitors

Abstract

Over the last years, the different polymorphs of MnO 2 have been intensely studied as alternative compounds to amorphous hydrous RuO 2 as supercapacitor electrode materials. In the present work, nanosized birnessite-type MnO 2 platelets were synthesized via the polyol method followed by a subsequent ligand removal with NaOH. The resulting compound is easily dispersible in polar solvents, thus allowing the preparation of stable dispersions (2-3 days) that could be used in thin electrode preparation. The capacitance of the synthesized product was 130 F g -1 in a potential window of 0.8 V at a scan rate of 2 mV s -1 . The synthesized material was also studied using a cavity microelectrode to evaluate the electrochemical performance of the nanostructured oxide at high scan rates. Cyclic voltammetry measurements were successfully carried out both in the previous potential window between 0.1 and 0.9 V (vs. SHE) and in a larger potential window between -0.6 and 1.1 V (vs. SHE) from 0.1 and up to 1,000 mV s -1 . Therefore, herein prepared material could be potentially used for high power applications, although further work should be carried out to upscale such compound without compromising the performance.

Simultaneous electrochemical deposition of an e-rGO/β-CD/MnO2 ternary composite for a self-powered supercapacitor based caffeine sensor

“…A new intense peak at 564 cm À1 is observed, which corroborates the presence of MnO 2 . 50 These results conrm the incorporation of MnO 2 with rGO and b-CD for composite formation (Fig. 4).…”

XRD/Raman spectroscopy studies of the mechanism of (de)intercalation of Na+ from/into highly crystalline birnessite

“…This shape variation is highlighted while normalizing the CVs in current, which is performed by simply dividing the current by the scan rate just as shown in Figure 5. 41 The redox peaks were labelled as depicted in Figure 5, where the peaks observed during the anodic scan and the cathodic scan are labelled A and C, respectively. The occurrence of defined redox peaks is different from what often has been observed for poorly crystalline, small particle size birnessite, for which nearly rectangular CV curves 42 , referred to as "pseudocapacitive", are often observed 30,[43][44][45] .…”

Superkondentsadoreak: Energia Biltzeko Gailuak

“…Superkondentsagailuak: energia biltegiratzeko gailuak tertu izan dugu, sintesi modu berriak erabiliz [22]. 5a.…”