Well‐Defined Nanostructures for Electrochemical Energy Conversion and Storage

Abstract

existing energy supply systems mainly based on fossil fuels, the performance of the clean energy (conversion and storage) devices/systems has to be significantly improved. The electrochemical energy conversion and storage usually involves many intricate chemical reactions and physical interactions at the surface and inside of electrodes/electrolytes, and the kinetics and transport behaviors of different carriers (e.g., electrons, holes, ions, molecules) are closely associated with the materials selected for electrodes as well as the structures of electrodes. To this point, material design and structure design for electrodes have been the research focuses for improving the electrochemical performance of energy conversion and storage, which both have gained high attention from academia and industry.Along with researches for finding advanced electrode materials, much recent research efforts have been made for electrode structure design and engineering, especially when traditional macro-scale structured electrodes are showing limitations of achieving satisfying performance for energy conversion and storage. Among these efforts, electrode nanostructuring has been demonstrated as a promising way for realizing highperformance electrochemical energy conversion and storage, which attributes the distinct features of nanostructured materials differing from their bulk material counterparts. The high surface-to-volume ratios of nanostructures give large electrochemical surface areas with much more exposed atoms and hence improve the performance per unit electrode area and/or Electrochemical energy conversion and storage play crucial roles in meeting the increasing demand for renewable, portable, and affordable power supplies for society. The rapid development of nanostructured materials provides an alternative route by virtue of their unique and promising effects emerging at nanoscale. In addition to finding advanced materials, structure design and engineering of electrodes improves the electrochemical performance and the resultant commercial competitivity. Regarding the structural engineering, controlling the geometrical parameters (i.e., size, shape, heteroarchitecture, and spatial arrangement) of nanostructures and thus forming well-defined nanostructure (WDN) electrodes have been the central aspects of investigations and practical applications. This review discusses the fundamental aspects and concept of WDNs for energy conversion and storage, with a strong emphasis on illuminating the relationship between the structural characteristics and the resultant electrochemical superiorities. Key strategies for actualizing well-defined features in nanostructures are summarized. Electrocatalysis and photoelectrocatalysis (for energy conversion) as well as metal-ion batteries and supercapacitors (for energy storage) are selected to illustrate the superiorities of WDNs in electrochemical reactions and charge carrier transportation. Finally, conclusions and perspectives regarding future research, development, and applications of WDNs...

Designing Oxide Aerogels With Enhanced Sorptive and Degradative Activity for Acute Chemical Threats

“…High surface-area oxides can also be synthesized through various template-based nanopatterning techniques. For electrocatalysts and photocatalysts, nanosphere lithography (Lee et al, 2017;Brinkert et al, 2018), nanoimprint lithography (Contreras et al, 2006;Xie et al, 2019), proximity-field nanopatterning (Ahn et al, 2013;Kim et al, 2019;Tiwari et al, 2020), and other similar methods (Xu et al, 2020) are widely explored to create highly porous, periodic structures that more effectively expose active sites than occurs with MOFs or zeolites. However, these templatebased approaches are typically applicable only to thin films supported on substrates, making them unsuitable for TIC/CW agent remediation where a large quantity of the freestanding material must be economically synthesized.…”

Novel Lamellar Tetrapotassium Pyromellitic Organic for Robust High‐Capacity Potassium Storage

“…Moreover, the typical scanning electron microscope (SEM) images of K 4 PM exhibit the lamellar structure (Figures 1 f and g) and corresponding energy disperse spectroscopy (EDS) mapping images further identify the uniform distribution of C, O, and K elements (Figure 1 h). According to the Brunauer‐Emmett‐Teller (BET) measurement, the synthesized K 4 PM has a specific surface area (31.90 m 2 g −1 ) and a large mesoporous volume (Figure S3), in favor of the fast ion diffusion [22] …”

Transition metal/carbon hybrids for oxygen electrocatalysis in rechargeable zinc‐air batteries

“…Recently, the hybrid systems integrating porous carbon nanostructures, transition metals (TMs) and doped heteroatom species have attracted considerable attentions for oxygen electrocatalysis in rechargeable ZABs 23,24 . Except their excellent stability and conductivity, the porous carbon nanostructures offer abundant active sites as well as shortened transport pathway, which improves reactants exchange and promotes electrochemical reaction kinetics at the liquid‐solid‐gas interface 25‐28 . Moreover, the doped heteroatoms in carbon skeleton combined with TM species can serve as electron donor or acceptor during the electrochemical process, resulting in the enhanced activity and energy conversion efficiency 29,30 .…”