Holey two-dimensional transition metal oxide nanosheets for efficient energy storage

Abstract

Transition metal oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance. However, detailed conversion reaction processes in terms of the oxidation state evolution and chemical/mechanical stability of the electrodes are still poorly understood. Herein we explore a general synthetic strategy for versatile synthesis of various holey transition metal oxide nanosheets with adjustable hole sizes that enable greatly enhanced alkali-ion storage properties. We employ in-situ transmission electron microscopy and operando X-ray absorption structures to study the mechanical properties, morphology evolution and oxidation state changes during electrochemical processes. We find that these holey oxide nanosheets exhibit strong mechanical stability inherited from graphene oxide, displaying minimal structural changes during lithiation/delithiation processes. These holey oxide nanosheets represent a promising material platform for in-situ probing the electrochemical processes, and could open up opportunities in many energy storage and conversion systems.

Holey 2D Nanomaterials for Electrochemical Energy Storage

“…Recently, Peng et al proposed a general method of in situ synthesis of 2D holey transition metal oxide (TMO) nanosheets. [26] Figure 4 shows the schematic illustration of the synthesis process of 2D holey TMO nanosheets. TM cations were first mixed with the GO template, and TMO/GO precursors were formed through the solutionbased growth.…”

“…[26] Tuning the calcination temperature, reaction recipes, etc., have been found crucial to control the hole size of the 2D holey TMO nanosheets. The as-obtained holey TMO nanosheets showed interconnected holey architectures (Figure 10a), effectively facilitating the electrolyte penetration into the electrodes and greatly shortening the ion transport pathway (Figure 10b).…”

A Universal Strategy for Constructing Seamless Graphdiyne on Metal Oxides to Stabilize the Electrochemical Structure and Interface

“…[3,6] The nanostructured morphologies are beneficial to expose large surface area and interface, but severely reduce the conductivity, and structural and interfacial stabilities during the electrochemical processes. [3,6] The nanostructured morphologies are beneficial to expose large surface area and interface, but severely reduce the conductivity, and structural and interfacial stabilities during the electrochemical processes.…”

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applications, MOs are usually prepared into nanostructures with complex dimensions to enhance its performances, such as the 0D nanosphere, 1D nanorods, 2D nanosheets, and 3D hierarchical morphologies. [3,7] Recent studies have shown that carbon components are necessary to improve the activity, conductivity, and stability of MOs, [8,9] and the all-carbon modifications are definitely more stable than other inorganic ones. In them, the irreversible changes over the structure and interface are considered to be the main reason for hindering the practical applications of MOs.

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Effects of surface treatment on the electrocatalytic performance of Spinel NiCo2O4 and Carbon Nanotubes composite catalysts

“…This means that the structure plays a crucial part on their capacitive performance. As far as we know, nickel-cobalt spinels with the following configurations have been synthesized: nanosheet [19,20], nanoplate [21][22][23], nanoflower [24,25], nanotube [26][27][28], nanowire [29,30], and urchin-like nanostructures [31,32]. In addition, it was found that synthesis method and process condition of spinel oxides can significantly affect their electrochemical characteristics [33].…”