Graphene‐Assisted Room‐Temperature Synthesis of 2D Nanostructured Hybrid Electrode Materials: Dramatic Acceleration of the Formation Rate of 2D Metal Oxide Nanoplates Induced by Reduced Graphene Oxide Nanosheets

Abstract

A new prompt room temperature synthetic route to 2D nanostructured metal oxide-graphene-hybrid electrode materials can be developed by the application of colloidal reduced graphene oxide (RGO) nanosheets as an efficient reaction accelerator for the synthesis of δ-MnO2 2D nanoplates. Whereas the synthesis of the 2D nanostructured δ-MnO2 at room temperature requires treating divalent manganese compounds with persulfate ions for at least 24 h, the addition of RGO nanosheet causes a dramatic shortening of synthesis time to 1 h, underscoring its effectiveness for the promotion of the formation of 2D nanostructured metal oxide. To the best of our knowledge, this is the first example of the accelerated synthesis of 2D nanostructured hybrid material induced by the RGO nanosheets. The observed acceleration of nanoplate formation upon the addition of RGO nanosheets is attributable to the enhancement of the oxidizing power of persulfate ions, the increase of the solubility of precursor MnCO3, and the promoted crystal growth of δ-MnO2 2D nanoplates. The resulting hybridization between RGO nanosheets and δ-MnO2 nanoplates is quite powerful not only in increasing the surface area of manganese oxide nanoplate but also in enhancing its electrochemical activity. Of prime importance is that the present δ-MnO2 -RGO nanocomposites show much superior electrode performance over most of 2D nanostructured manganate systems including a similar porous assembly of RGO and layered MnO2 nanosheets. This result underscores that the present RGO-assisted solution-based synthesis can provide a prompt and scalable method to produce nanostructured hybrid electrode materials.

The beneficial effect of nanocrystalline and amorphous nature on the anode performance of manganese oxide for lithium ion batteries

“…This result strongly suggests that these X-ray amorphous AM-1 and AM-2 materials still have distinct local structural ordering and that their local structures are layer-type, as observed in the well-crystallized K 0.45 MnO 2 . For the solution-based soft-chemical synthesis used in the present study, it is well documented that only the a-, b-, g-, and d-MnO 2 phases can be formed [32,33]. To determine the precise local crystal structures of amorphous AM-1 and AM-2, the experimental spectra of these materials are compared with the simulated data of the a-, b-, g-, and d-MnO 2 phases.…”

Recent Applications of 2D Inorganic Nanosheets for Emerging Energy Storage System

“…In one instance, several TMOs, LDHs, and TMDs nanosheets were hybridized with rGO nanosheet, yielding promising supercapacitor electrode materials. The hybridization with rGO nanosheet not only improved the electrical conductivity of electrode material but also increased the surface and porosity of composite, leading to the improvement of electrode activity …”

“…The hybridization with rGO nanosheet not only improved the electrical conductivity of electrode materialb ut also increased the surfacea nd porosity of composite, leading to the improvement of electrode activity. [178] Even thought he hybridization with conductive rGOn anosheet is effective in optimizing the electrode functionality of inorganic solid, as trong p-p interaction between rGO nanosheets and the resultings elf-stacking makes it difficult to form homogeneous compositions.…”

Composition‐Tailored 2 D Mn1−xRuxO2 Nanosheets and Their Reassembled Nanocomposites: Improvement of Electrode Performance upon Ru Substitution

“…[10,[13][14][15][16] There are many reports about the application of low-dimensional nanostructured manganese oxides including 0 D hollow spheres, 1 D nanowires/ nanorods, 2 D nanosheets, and 3 D nanourchins for supercapacitor electrodes. [10,[15][16][17][18][19] Despite a great deal of research regarding the electrode application of nanostructured manganese oxides, [3,10,[14][15][16][17][18][19][20] there is still a need to further improve the electrode performance of these materials. In comparison with powdery manganese oxides, several thin films of nanostructured manganese oxides display much larger specific capacitance per unit mass, which is attributable to the large surface area of nanostructured electrode films and the short distance between electrode materials and current collector.…”