4 research outputs found
Enhanced Cycling Stability of Hybrid Li–Air Batteries Enabled by Ordered Pd<sub>3</sub>Fe Intermetallic Electrocatalyst
We report an ordered Pd<sub>3</sub>Fe intermetallic catalyst that
exhibits significantly enhanced activity and durability for the oxygen
reduction reaction under alkaline conditions. Ordered Pd<sub>3</sub>Fe enables a hybrid Li–air battery to exhibit the best reported
full-cell cycling performance (220 cycles, 880 h)
Understanding the Redox Obstacles in High Sulfur-Loading Li–S Batteries and Design of an Advanced Gel Cathode
Lithium–sulfur batteries with
a high energy density are
being considered a promising candidate for next-generation energy
storage. However, realization of Li–S batteries is plagued
by poor sulfur utilization due to the shuttle of intermediate lithiation
products between electrodes and its dynamic redistribution. To optimize
the sulfur utilization, an understanding of its redox behavior is
essential. Herein, we report a gel cathode consisting of a polysulfide-impregnated
O- and N-doped porous carbon and an independent, continuous, and highly
conducting 3-dimensional graphite film as the charge-transfer network.
This design decouples the function of electron conduction and polysulfide
absorption, which is beneficial for understanding the sulfur redox
behavior and identifying the dominant factors leading to cell failure
when the cells have high sulfur content and insufficient electrolyte.
This design also opens up new prospects of tuning the properties of
Li–S batteries via separately designing the material functions
of electron conduction and polysulfide absorption
Materials Genomics Screens for Adaptive Ion Transport Behavior by Redox-Switchable Microporous Polymer Membranes in Lithium–Sulfur Batteries
Selective ion transport across membranes
is critical to the performance
of many electrochemical energy storage devices. While design strategies
enabling ion-selective transport are well-established, enhancements
in membrane selectivity are made at the expense of ionic conductivity.
To design membranes with both high selectivity and high ionic conductivity,
there are cues to follow from biological systems, where regulated
transport of ions across membranes is achieved by transmembrane proteins.
The transport functions of these proteins are sensitive to their environment:
physical or chemical perturbations to that environment are met with
an adaptive response. Here we advance an analogous strategy for achieving
adaptive ion transport in microporous polymer membranes. Along the
polymer backbone are placed redox-active switches that are activated
in situ, at a prescribed electrochemical potential, by the device’s
active materials when they enter the membrane’s pore. This
transformation has little influence on the membrane’s ionic
conductivity; however, the active-material blocking ability of the
membrane is enhanced. We show that when used in lithium–sulfur
batteries, these membranes offer markedly improved capacity, efficiency,
and cycle-life by sequestering polysulfides in the cathode. The origins
and implications of this behavior are explored in detail and point
to new opportunities for responsive membranes in battery technology
development
Antiplatelet effects of the CEACAM1-derived peptide QDTT
Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) restricts platelet activation via platelet collagen receptor GPVI/FcRγ-chain. In this study, screening against collagen-induced platelet aggregation was performed to identify functional CEACAM1 extracellular domain fragments. CEACAM1 fragments, including Ala-substituted peptides, were synthesized. Platelet assays were conducted on healthy donor samples for aggregation, cytotoxicity, adhesion, spreading, and secretion. Mice were used for tail bleeding and FeCl3-induced thrombosis experiments. Clot retraction was assessed using platelet-rich plasma. Extracellular segments of CEACAM1 and A1 domain-derived peptide QDTT were identified, while N, A2, and B domains showed no involvement. QDTT inhibited platelet aggregation. Ala substitution for essential amino acids (Asp139, Thr141, Tyr142, Trp144, and Trp145) in the QDTT sequence abrogated collagen-induced aggregation inhibition. QDTT also suppressed platelet secretion and “inside-out” GP IIb/IIIa activation by convulxin, along with inhibiting PI3K/Akt pathways. QDTT curtailed FeCl3-induced mesenteric thrombosis without significantly prolonging bleeding time, implying the potential of CEACAM1 A1 domain against platelet activation without raising bleeding risk, thus paving the way for novel antiplatelet drugs. What is the context?The study focuses on Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) and its role in platelet activation, particularly through the GPVI/FcRγ-chain pathway.The research aims to identify specific fragments of CEACAM1’s extracellular domain that could restrict platelet activation, without increasing bleeding risk. The study focuses on Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) and its role in platelet activation, particularly through the GPVI/FcRγ-chain pathway.The research aims to identify specific fragments of CEACAM1’s extracellular domain that could restrict platelet activation, without increasing bleeding risk. What is new?The researchers identified a peptide called QDTT derived from the A1 domain of CEACAM1’s extracellular segment. This peptide demonstrated the ability to inhibit platelet aggregation, secretion, and GP IIb/IIIa activation.The study also revealed that specific amino acids within the QDTT sequence were essential for its inhibitory effects on collagen-induced aggregation. The researchers identified a peptide called QDTT derived from the A1 domain of CEACAM1’s extracellular segment. This peptide demonstrated the ability to inhibit platelet aggregation, secretion, and GP IIb/IIIa activation. The study also revealed that specific amino acids within the QDTT sequence were essential for its inhibitory effects on collagen-induced aggregation. What is the impact?The findings suggest that the A1 domain-derived peptide QDTT from CEACAM1 could serve as a potential basis for developing novel antiplatelet drugs. This peptide effectively limits platelet activation and aggregation without significantly prolonging bleeding time, indicating a promising approach to managing thrombosis and related disorders while minimizing bleeding risks. The findings suggest that the A1 domain-derived peptide QDTT from CEACAM1 could serve as a potential basis for developing novel antiplatelet drugs. This peptide effectively limits platelet activation and aggregation without significantly prolonging bleeding time, indicating a promising approach to managing thrombosis and related disorders while minimizing bleeding risks.</p