Unilamellar Nanosheet of Layered Manganese Cobalt Nickel Oxide and Its Heterolayered Film with Polycations

Abstract

The exfoliation of layered Li[Mn(1/3)Co(1/3)Ni(1/3)]O(2) into individual monolayers could be achieved through the intercalation of quaternary tetramethylammonium (TMA(+)) ions into protonated metal oxide. An effective exfoliation occurred when the TMA(+)/H(+) ratio was 0.5-50. Reactions outside this range produced no colloidal suspension, but all the manganese cobalt nickel oxides precipitated. Atomic force microscopy and transmission electron microscopy clearly demonstrated that exfoliated manganese cobalt nickel oxide nanosheets have a nanometer-level thickness, underscoring the formation of unilamellar nanosheets. The maintenance of the hexagonal atomic arrangement of the manganese cobalt nickel oxide layer upon the exfoliation was confirmed by selected area electron diffraction analysis. According to diffuse reflectance ultraviolet--visible spectroscopy, the exfoliated manganese cobalt nickel oxides displayed distinct absorption peaks at approximately 354 and approximately 480 nm corresponding to the d-d transitions of octahedral metal ions, which contrasted with the featureless spectrum of the pristine metal oxide. In the light of zeta potential data showing the negative surface charge of manganese cobalt nickel oxide nanosheets, a heterolayered film of manganese cobalt nickel oxide and conductive polymers could be prepared through the successive coating process with colloidal suspension and polycations. The UV--vis and X-ray diffraction studies verified the layer-by-layer ordered structure of the obtained heterolayered film, respectively.

Advanced Li-Rich Cathode Collaborated with Graphite/Silicon Anode for High Performance Li-Ion Batteries in Half and Full Cells

“…The spotted SAED pattern demonstrates the single-crystalline nature of the core part of . Besides, as is reported previously[27][28][29][30], the strong reflections in the SAED pattern can be indexed to rhombohedral phase LiMO 2 , while the weak reflections which illustrate the ordering of lithium with the transition metal ion (Mn ions) in the transition metal layer are uniquely identified as the monoclinic (C2/m) Li 2 MnO 3 -like component. Additionally, unconspicuous diffraction rings are observed in both Fig.…”

A Direct Hybridization between Isocharged Nanosheets of Layered Metal Oxide and Graphene through a Surface‐Modification Assembly Process

“…[9][10][11][12][13] Redox active metal oxide nanosheets such as CoO 2 , MnO 2 , and [Mn 1/3 Co 1/3 Ni 1/3 ]O 2 can be used as efficient electrode materials for lithium-ion batteries, supercapacitors, redox catalysts, etc. [14][15][16] Many of these functionalities of the exfoliated inorganic nanosheets can be further improved by hybridization with highly conductive graphene nanosheets. In fact, hybridization between the cationic layered double hydroxide (LDH) nanosheet and the chemically prepared reduced graphene oxide (rGO) nanosheet is fairly effective in optimizing the photocatalytic and electrochemical activity of the LDH materials.…”

Mixed Colloidal Suspensions of Reduced Graphene Oxide and Layered Metal Oxide Nanosheets: Useful Precursors for the Porous Nanocomposites and Hybrid Films of Graphene/Metal Oxide

“…[3][4][5] One of the most useful chemical methods to synthesize 2D nanosheets is an exfoliation of layered inorganic solids into individual layers. [6][7][8] The exfoliated 2D nanosheets are obtained in the form of a stable colloidal suspension in aqueous media or organic solvent. [7,8] A distinct surface charge of exfoliated colloidal nanosheets renders them powerful building blocks for many novel hybrid materials such as intercalative nanohybrids, layer-by-layer-ordered multilayer films, hollow spheres, and so on.…”

“…[6][7][8] The exfoliated 2D nanosheets are obtained in the form of a stable colloidal suspension in aqueous media or organic solvent. [7,8] A distinct surface charge of exfoliated colloidal nanosheets renders them powerful building blocks for many novel hybrid materials such as intercalative nanohybrids, layer-by-layer-ordered multilayer films, hollow spheres, and so on. [7][8][9][10] The reassembling of anionic transition-metal oxide nanosheets with cationic guest species yields highly porous pillared metal oxides with a tailored pore structure and strongly coupled electronic structure.…”

“…[7,8] A distinct surface charge of exfoliated colloidal nanosheets renders them powerful building blocks for many novel hybrid materials such as intercalative nanohybrids, layer-by-layer-ordered multilayer films, hollow spheres, and so on. [7][8][9][10] The reassembling of anionic transition-metal oxide nanosheets with cationic guest species yields highly porous pillared metal oxides with a tailored pore structure and strongly coupled electronic structure. [10][11][12][13] If we take into account the remarkably expanded surface area and redox capability of component transition-metal ions, the reassembled nanohybrids of transition-metal oxide nanosheets are supposed to show promising electrode performance for supercapacitors and lithium-ion batteries.…”