Porous Hybrid Network of Graphene and Metal Oxide Nanosheets as Useful Matrix for Improving the Electrode Performance of Layered Double Hydroxides

Abstract

Mesoporous hybrid network of reduced graphene oxide (rG-O) and layered MnO(2) nanosheets could act as an efficient immobilization matrix for improving the electrochemical activity of layered double hydroxide (LDH). The control of MnO(2) /rG-O ratio is crucial in optimizing the porous structure and electrical conductivity of the resulting hybrid structure. The immobilization of Co-Al-LDH on hybrid MnO(2) /rG-O network is more effective in enhancing its electrode activity compared with that of on pure rG-O network. The Co-Al-LDH-rG-O-MnO(2) nanohybrid deliveres a greater specific capacitance than does MnO(2) -free Co-Al-LDH-rG-O nanohybrid. The beneficial effect of MnO(2) incorporation on the electrode performance of nanohybrid is more prominent for higher current density and faster scan rate, underscoring the significant enhancement of the electron transport of Co-Al-LDH-rG-O. This is supported by electrochemical impedance spectroscopy. The present study clearly demonstrates the usefulness of the porously assembled hybrid network of graphene and metal oxide nanosheets as an effective platform for exploring efficient LDH-based functional materials.

Graphene based metal and metal oxide nanocomposites: synthesis, properties and their applications

“…362 LDHs are well-known anionic or hydrotalcite-like clays. Typically, they contain divalent and trivalent cations and a variety of organic or inorganic anions.…”

“…Typically, they contain divalent and trivalent cations and a variety of organic or inorganic anions. 362 Gao et al reported the hydrothermal synthesis of HRG/NiAl LDH nanocomposites, where Ni/Al LDH platelets were formed in situ on the graphene surface. 363 The LDA/graphene composite was comprised of thin hexagonal platelets with diameters of 50 nm, decorated on the graphene sheets as a loose lamellar structure.…”

A 2D Metal Oxide Nanosheet as an Efficient Additive for Improving Na‐Ion Electrode Activity of Graphene‐Based Nanocomposites

“…Considering that the XANES result indicates the incorporation of the SnS 2 nanosheets into the present NSGT nanocomposites, the absence of SnS 2 -related Ramanp eak for the titanate-incorporated nanocomposites is attributed to the enhanced interaction with highly conductive rG-O nanosheets by the addition of the titanate nanosheet, leading to the complete shielding of SnS 2 -related Ramans catteringb yt he p-electron clouds of an eighboring graphene nanosheet. [17] Ta king into account the fact that the titanate-free NSGT0 nanocomposite displays distinct SnS 2 -related Ramanp eaks, this observation can be interpreteda ss trong evidence for the enhanced mixing between SnS 2 and rG-O upon the incorporation of the titanatenanosheet.…”

“…[12,13] Judging from the 2D sheet-like morphology of metal dichalcogenide, the composite formation with ah ighly conductive graphene 2D nanosheet is supposed to provide an effective approach to improve the sodium-ion electrode functionality of metal dichalcogenidet hrough the enhancement of electrical conductivity.A lthought here are several reports about the coupling of metal dichalcogenide with reduced graphene oxide (rG-O), [14][15][16] the strong self-stackingt endency of rG-O prevents it from intimately mixing with metal dichalcogenide nanosheets. Because exfoliated metal oxide nanosheets can form ah omogenousc olloidal mixture with rG-O duet ot heir similar surfacen ature and crystal morphology, [17][18][19] this metal oxide nanosheet can be easily incorporated into the restacked rG-O matrix. The intervention of am etal oxide nanosheet gives rise to the optimization of the pore structure of metal dichalcogenide-rG-On anocomposites by preventing the severe selfstacking of rG-O nanosheets.…”

“…The intervention of am etal oxide nanosheet gives rise to the optimization of the pore structure of metal dichalcogenide-rG-On anocomposites by preventing the severe selfstacking of rG-O nanosheets. [17][18][19] The resulting increase of porosity with surface expansion leads to more reaction sites for the anchoring of Na + ions and the improvemento fN a + ion transport, therebyi ncreasing the Na-ion storage capacity.T he accompanying enhanced electronic coupling of metal chalcogenide with metallic rG-O upon incorporation of am etal oxide nanosheet is also beneficiali ne nhancing the electrode functionality of metal dichalcogenide-rG-O nanocomposites. Yet, to the best of our knowledge, there is no report about the use of an exfoliated metal oxide nanosheet as an additive for the synthesis of efficient NIB anode materials.…”