Li‐chalcogen batteries, especially the Li–S batteries (LSBs), have received paramount interests as next generation energy storage techniques because of their high theoretical energy densities. ...However, the associated challenges need to be overcome prior to their commercialization. Elemental selenium, another chalcogen member, would be an attractive alternative to sulfur owing to its higher electronic conductivity, comparable capacity density, and moreover, excellent compatibility with carbonate electrolytes. Unlike LSBs, the research and development of Li–Se batteries (LSeBs) have garnered burgeoning attention but are still in their infant stage, where a comprehensive yet in‐depth overview is highly imperative to guide future research. Herein, a critical review of LSeBs, in terms of the underlying mechanisms, cathode design, blocking layer engineering, and emerging solid‐state electrolytes is provided. First, the electrolyte‐dependent electrochemistry of LSeBs is discussed. Second, the advances in Se‐based cathodes are comprehensively summarized, especially highlighting the state‐of‐the‐art SexSy cathodes, and mainly focusing on their structures, compositions, and synthetic strategies. Third, the versatile separators/interlayers optimization and interface regulation are outlined, with a particular focus on the emerging solid‐state electrolytes for advanced LSeBs. Last, the remaining challenges and research orientations in this booming field are proposed, which are expected to motivate more insightful works.
Li–Se batteries (LSeBs) have garnered intensive attention since the Se cathode possesses high capacity and electronic conductivity. LSeBs experience a solid‐to‐solid transformation accompanied by side reactions in carbonate electrolytes but multiphase conversion in ether‐based ones. The advances for cathode design, blocking layer engineering, and emerging solid‐state electrolytes are summarized. The future research directions are also outlined to motivate further insightful work.
Lithium–chalcogen batteries are an appealing choice for high‐energy‐storage technology. However, the traditional battery that employs liquid electrolytes suffers irreversible loss and shuttle of the ...soluble intermediates. New batteries that adopt Li+‐conductive polymer electrolytes to mitigate the shuttle problem are hindered by incomplete discharge of sulfur/selenium. To address the trade‐off between energy and cycle life, a new electrolyte is proposed that reconciles the merits of liquid and polymer electrolytes while resolving each of their inferiorities. An in situ interfacial polymerization strategy is developed to create a liquid/polymer hybrid electrolyte between a LiPF6‐coated separator and the cathode. A polymer‐gel electrolyte in situ formed on the separator shows high Li+ transfer number to serve as a chemical barrier against the shuttle effect. Between the gel electrolyte and the cathode surface is a thin gradient solidification layer that enables transformation from gel to liquid so that the liquid electrolyte is maintained inside the cathode for rapid Li+ transport and high utilization of active materials. By addressing the dilemma between the shuttle chemistry and incomplete discharge of S/Se, the new electrolyte configuration demonstrates its feasibility to trigger higher capacity retention of the cathodes. As a result, Li–S and Li–Se cells with high energy and long cycle lives are realized, showing promise for practical use.
The rational reconfiguration of an electrolyte enabled by an in situ interfacial polymerization strategy is demonstrated. This strategy endows Li–S and Li–Se batteries with high capacity, stable cycling, and excellent rate performances simultaneously, and may become a new pathway toward the large‐scale and cost‐effective applications of future Li metal batteries.
Lithium-selenium (Li–Se) batteries represent a promising energy storage system due to the relatively high electronic conductivity and high volumetric energy density of Se as a cathode. The design of ...porous carbon with tunable structure and low cost is a key to enabling Se cathodes for high-performance Li–Se batteries. In this study, hierarchically microporous activated carbon (AC) was fabricated from waste coffee grounds through a carbonization and KOH-activation process. Despite the simple synthesis process, the optimized AC (AC-700) had a high surface area of 1355 m2 g−1 and a large microspore volume of 0.52 cm³ g−1. The Se/AC-700 cathode showed a reversible capacity of 655 mAh g−1 after 100 cycles at 0.1C in Li–Se batteries based on a carbonate electrolyte. Moreover, the Se/AC-700 cathode demonstrated excellent cyclic performance over 400 cycles without appreciable capacity decay. The main reason for the good battery performance was attributed to fast electron transfer and Li-ion diffusion in Se confined in the microporous carbon of AC-700. It is expected that this work will shed light on the development of low-cost and stable Se cathodes for high-energy Li–Se batteries.
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•Microporous carbon is synthesized from waste coffee grounds (WCG).•WCG-derived carbon is used as a Se cathode host in Li–Se batteries.•Se/carbon cathode exhibits high a reversible capacity and long cycling life.•Micropores in carbon are key to enabling fast e− transfer and Li+ diffusion in Se.
High energy density batteries and high power density supercapacitors have attracted much attention because they are crucial to the power supply of future portable electronic devices, electric ...automobiles, unmanned aerial vehicles, etc. The electrode materials are key components for batteries and supercapacitors, which influence the practical energy and power density. Metal-organic frameworks possessing unique morphology, high specific surface area, functional linkers, and metal sites are excellent electrode materials for electrochemical energy storage devices. Herein, we review and comment on recent progress in metal-organic framework-based lithium-ion batteries, sodium-ion batteries, lithium-air batteries, lithium-sulfur/selenium batteries, and supercapacitors. Future perspectives and directions of metal-organic framework-based electrochemical energy storage devices are put forward on the basis of theoretical knowledge from the reported literature and our experimental experience.
Embedding the fragmented selenium into the micropores of carbon host has been regarded as an effective strategy to change the Li–Se chemistry by a solid–solid mechanism, thereby enabling an excellent ...cycling stability in Li–Se batteries using carbonate electrolyte. However, the effect of spatial confinement by micropores in the electrochemical behavior of carbon/selenium materials remains ambiguous. A comparative study of using both microporous (MiC) and mesoporous carbons (MeC) with narrow pore size distribution as selenium hosts is herein reported. Systematic investigations reveal that the high Se utilization rate and better electrode kinetics of MiC/Se cathode than MeC/Se cathode may originate from both its improved Li+ and electronic conductivities. The small pore size (<1.35 nm) of the carbon matrices not only facilitates the formation of a compact and robust solid‐electrolyte interface (SEI) with low interfacial resistance on cathode, but also alters the insulating nature of Li2Se due to the emergence of itinerant electrons. By comparing the electrochemical behavior of MiC/Se cathode and the matching relationship between the diameter of pores and the dimension of solvent molecules in carbonate, ether, and solvate ionic liquid electrolyte, the key role of SEI film in the operation of C/Se cathode by quasi‐solid‐solid mechanism is also highlighted.
For microporous carbon/Se cathode in carbonate electrolyte, micropores facilitate the formation of thin LiF‐rich solid electrolyte interphase on the C/Se cathode, allowing fast Li+ conduction. The nanoconfinement of micropores can generate the itinerant electrons and alter the insulating nature of Li2Se.
•The three combinations which have been studied in recent years were detailed listed.•The methods of obtaining the three combinations were detailed described respectively.•The therapeutic potential ...of the three combinations were detailed described.
Currently, selenium and polysaccharide combinations can be identified as three forms: natural selenium polysaccharides, synthetic selenium polysaccharides and selenium nanoparticles decorated with polysaccharides. Previous studies have indicated that these three combinations generally show better bioactivities, including immunomodulation, anti-tumour, antioxidation and glucose regulation, than those of either selenium or polysaccharides alone. Although they have not yet been developed as new drugs for clinical trials, results from previous studies have already shown their therapeutic potential for the future. In this article, we summarize our current state of understanding of the sources, preparation methods, physicochemical characteristics and bioactivities of these combinations for the discovery of novel therapeutic drugs and adjuvants.
Development of high‐performance organic thermoelectric (TE) materials is of vital importance for flexible power generation and solid‐cooling applications. Demonstrated here is the significant ...enhancement in TE performance of selenium‐substituted diketopyrrolopyrrole (DPP) derivatives. Along with strong intermolecular interactions and high Hall mobilities of 1.0–2.3 cm2 V−1 s−1 in doping‐states for polymers, PDPPSe‐12 exhibits a maximum power factor and ZT of up to 364 μW m−1 K−2 and 0.25, respectively. The performance is more than twice that of the sulfur‐based DPP derivative and represents the highest value for p‐type organic thermoelectric materials based on high‐mobility polymers. These results reveal that selenium substitution can serve as a powerful strategy towards rationally designed thermoelectric polymers with state‐of‐the‐art performances.
Packed in: A high‐performance p‐type organic thermoelectric material based on a selenium‐substituted diketopyrrolopyrrole (DPP) polymer was developed. With strong intermolecular interactions and ordered molecular packing, PDPPSe‐12 exhibits high Hall mobilities of 1.0–2.3 cm2 V−1 s−1 in doped states, yielding a maximum PF and ZT value of 364 μW m−1 K−2 and 0.25, respectively.
To address the urgent need for clean and sustainable energy, the rapid development of hydrogen‐based technologies has started to revolutionize the use of earth‐abundant noble‐metal‐free catalysts for ...the hydrogen evolution reaction (HER). Like the active sites of hydrogenases, the cation sites of pyrite‐type transition‐metal dichalcogenides have been suggested to be active in the HER. Herein, we synthesized electrodes based on a Se‐enriched NiSe2 nanosheet array and explored the relationship between the anion sites and the improved hydrogen evolution activity through theoretical and experimental studies. The free energy for atomic hydrogen adsorption is much lower on the Se sites (0.13 eV) than on the Ni sites (0.87 eV). Notably, this electrode benefits from remarkable kinetic properties, with a small overpotential of 117 mV at 10 mA cm−2, a low Tafel slope of 32 mV per decade, and excellent stability. Control experiments showed that the efficient conversion of H+ into H2 is due to the presence of an excess of selenium in the NiSe2 nanosheet surface.
Excess selenium: Although the undercoordinated surface metal centers of pyrite‐type transition‐metal dichalcogenides have been suggested to be the main active sites for H2 production, the ligand composition also plays a decisive role. The Se sites and excessive Se atoms on the surface of pyrite‐type NiSe2 are now corroborated to be the active sites for electrochemical H2 evolution.
Arylation Chemistry for Bioconjugation Zhang, Chi; Vinogradova, Ekaterina V.; Spokoyny, Alexander M. ...
Angewandte Chemie (International ed.),
April 1, 2019, Volume:
58, Issue:
15
Journal Article
Peer reviewed
Open access
Bioconjugation chemistry has been used to prepare modified biomolecules with functions beyond what nature intended. Central to these techniques is the development of highly efficient and selective ...bioconjugation reactions that operate under mild, biomolecule compatible conditions. Methods that form a nucleophile–sp2 carbon bond show promise for creating bioconjugates with new modifications, sometimes resulting in molecules with unparalleled functions. Here we outline and review sulfur, nitrogen, selenium, oxygen, and carbon arylative bioconjugation strategies and their applications to modify peptides, proteins, sugars, and nucleic acids
Bioconjugation: This article outlines and reviews sulfur, nitrogen, selenium, oxygen, and carbon arylative bioconjugation strategies and their applications to modify peptides, proteins, sugars, and nucleic acids.
Natural photosynthesis serves as a model for energy and chemical conversions, and motivates the search of artificial systems that mimic nature′s energy‐ and electron‐transfer chains. However, ...bioinspired systems often suffer from the partial or even large loss of the charge separation state, and show moderate activity owing to the fundamentally different features of the multiple compounds. Herein, a selenium and cyanamide‐functionalized heptazine‐based melon (DA‐HM) is designed as a unique bioinspired donor–acceptor (D‐A) light harvester. The combination of the photosystem and electron shuttle in a single species, with both n‐ and p‐type conductivities, and extended spectral absorption, endows DA‐HM with a high efficiency in the transfer and separation of photoexcited charge carriers, resulting in photochemical activity. This work presents a unique conjugated polymeric system that shows great potential for solar‐to‐chemical conversion by artificial photosynthesis.
Melon motifs: Biomimetic donor–acceptor motifs were introduced in melon‐based carbon nitride semiconductors to promote exciton dissociation and charge separation. This work presents a simple version of a biomimetic polymeric system that shows great potential for solar‐to‐chemical energy conversion through artificial photosynthesis, and it provides the structural basis for designing photochemical conversion systems having bioinspired functions.
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