Scalable sonochemical synthesis of petal-like MnO2/graphene hierarchical composites for high-performance supercapacitors

Density effects of vertical graphene nanowalls on supercapacitor performance

“…3(b), the C 1s spectrum can be deconvoluted into three peaks centered at 284.6 eV, 286.1 eV, and 288.0 eV, corresponding to the bonding types of C-C, CQO, and O-CQO, respectively. 46,47 The C-C bonding agrees with the SEM and TEM results, showing the successful growth of VG nanowalls. 48 Furthermore, the two peaks deconvoluted from the O 1s high-resolution spectrum with the binding energy at the centers of 529.7 eV and 530.9 eV present the Mn-O-Mn and C-O bonds as shown in Fig.…”

“…49,50 Moreover, the spin energy separation of 11.7 eV in Mn 2p split into Mn 2p 1/2 (654.6 eV) and Mn 2p 3/2 (642.9 eV) suggests the presence of Mn 4+ , indicating the formation of MnO 2 via electrochemical methods. 33,47 Fig. 3(e) shows the Raman spectra of VG 1:2.5 and MnO 2 / VG 1:2.5 .…”

Synergistic Optimization Strategy Involving Sandwich-like MnO2@rGO and Laponite-Modified PAM for High-Performance Zinc-Ion Batteries and Zinc Dendrite Suppression

“…The content of rGO in the MnO 2 @8%rGO composite material was studied by the TGA measurement under an air atmosphere, as exhibited in Figure S5. The weight loss that appears <200 °C is due to the evaporation of physically adsorbed water, and the weight loss at 200–800 °C is due to the decomposition of the remaining oxygen-containing groups in rGO and the whole degradation of carbon skeleton, a rGO content of 6.5% in MnO 2 @8%rGO can be found.…”

Influence of electrochemical active surface area on the oxygen evolution reaction and energy storage performance ofMnO2‐multiwalledcarbon nanotube composite

“…[9][10][11][12][13][14][15][16][17] There are plenty of reports on TMOs-based supercapacitors but they lack in terms of power density (compared to carbonaceous materials or electrostatic capacitors) and long-term cyclic stability due to their poor electrical conductivity, low structural, and chemical stability. Thus, a suitable alternative electrode material should be free from those shortcomings and maybe a combination of both TMOs and carbonaceous materials which will provide both high energy density, high power density, and long-term stability because of the large volumetric change during chargedischarge process 18,19 and carbonaceous materials providing the conducting pathway for electrical conduction as well as can increase the stability during charge/discharge. 20 Several groups have implemented this technique successfully by incorporating carbon nanotubes (CNTs) or graphene within MnO 2 or some other TMOs to obtain better performances compared to individual components.…”