scholarly journals A Chemical Map of NaSiCON Electrode Materials for Sodium-ion Batteries

2020 ◽  
Author(s):  
Baltej Singh Gill ◽  
Ziliang Wang ◽  
Sunkyu Park ◽  
Gopalakrishnan Sai Gautam ◽  
Jean-Nöel Chotard ◽  
...  
Keyword(s):  
Smart Grids ◽  
Electrode Materials ◽  
Chemical Space ◽  
Positive Electrode ◽  
First Principles Calculations ◽  
Thermal Stabilities ◽  
Chemical Systems ◽  
Wide Range ◽  
Na Ions ◽  
Electrochemical Potentials

<div><div><div><p>Na-ion batteries are promising devices for smart grids and electric vehicles due to cost effectiveness arising from the overall abundance of sodium (Na) and its even geographical distribution. Among other factors, the energy density of Na-ion batteries is limited by the positive electrode chemistry. NaSICON-based positive electrode materials are known for their wide range of electrochemical potentials,[1],[2],[3] high ionic conductivity, and most importantly their structural and thermal stabilities. Using first- principles calculations, we chart the chemical space of 3<i>d</i> transition metal-based NaSICON phosphates of formula Na<sub>x</sub>MM’(PO<sub>4</sub>)<sub>3</sub> (with M and M’= Ti, V, Cr, Mn, Fe, Co and Ni), to analyze their thermodynamic stabilities and the intercalation voltages for Na+ ions. Specifically, we computed the Na insertion voltages and related properties of 28 distinct NaSICON compositions. We investigated the thermodynamic stability of Na-intercalation in previously unreported NaxMn<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and Na<sub>x</sub>VCo(PO<sub>4</sub>)<sub>3</sub>. The calculated quaternary phase diagrams of the Na-P-O-Co and Na-P-O-Ni chemical systems explain the origin of the suspected instability of Ni and Co-based NaSICON compositions. From our analysis, we are also able to rationalize anomalies in previously reported experimental data in this diverse and important chemical space.</p></div></div></div>

scholarly journals A Chemical Map of NaSiCON Electrode Materials for Sodium-ion Batteries

2020 ◽  
Author(s):  
Baltej Singh Gill ◽  
Ziliang Wang ◽  
Sunkyu Park ◽  
Gopalakrishnan Sai Gautam ◽  
Jean-Nöel Chotard ◽  
...  
Keyword(s):  
Smart Grids ◽  
Electrode Materials ◽  
Chemical Space ◽  
Positive Electrode ◽  
First Principles Calculations ◽  
Thermal Stabilities ◽  
Chemical Systems ◽  
Wide Range ◽  
Na Ions ◽  
Electrochemical Potentials

<div><div><div><p>Na-ion batteries are promising devices for smart grids and electric vehicles due to cost effectiveness arising from the overall abundance of sodium (Na) and its even geographical distribution. Among other factors, the energy density of Na-ion batteries is limited by the positive electrode chemistry. NaSICON-based positive electrode materials are known for their wide range of electrochemical potentials,[1],[2],[3] high ionic conductivity, and most importantly their structural and thermal stabilities. Using first- principles calculations, we chart the chemical space of 3<i>d</i> transition metal-based NaSICON phosphates of formula Na<sub>x</sub>MM’(PO<sub>4</sub>)<sub>3</sub> (with M and M’= Ti, V, Cr, Mn, Fe, Co and Ni), to analyze their thermodynamic stabilities and the intercalation voltages for Na+ ions. Specifically, we computed the Na insertion voltages and related properties of 28 distinct NaSICON compositions. We investigated the thermodynamic stability of Na-intercalation in previously unreported NaxMn<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and Na<sub>x</sub>VCo(PO<sub>4</sub>)<sub>3</sub>. The calculated quaternary phase diagrams of the Na-P-O-Co and Na-P-O-Ni chemical systems explain the origin of the suspected instability of Ni and Co-based NaSICON compositions. From our analysis, we are also able to rationalize anomalies in previously reported experimental data in this diverse and important chemical space.</p></div></div></div>

scholarly journals A chemical map of NaSICON electrode materials for sodium-ion batteries

2021 ◽  
Vol 9 (1) ◽  
pp. 281-292
Author(s):  
Baltej Singh ◽  
Ziliang Wang ◽  
Sunkyu Park ◽  
Gopalakrishnan Sai Gautam ◽  
Jean-Noël Chotard ◽  
...  
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Electrode Materials ◽  
Chemical Space ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
First Principles Calculations

Using first-principles calculations, we chart the chemical space of 3d transition metal-based NaSICON phosphates with the formula NaxMM′(PO4)3 (with M and M′ = Ti, V, Cr, Mn, Fe, Co and Ni). Novel NaSICON compositions were revealed.

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

Structure and Activity of Pentacyclic Triterpenes Codrugs. A Review

2021 ◽  
Vol 21 ◽  
Author(s):  
Justyna Żwawiak ◽  
Anna Pawełczyk ◽  
Dorota Olender ◽  
Lucjusz Zaprutko
Keyword(s):  
Biological Activities ◽  
Anticancer Activities ◽  
Drug Molecule ◽  
Pentacyclic Triterpene ◽  
Formation Pathway ◽  
Chemical Systems ◽  
Drug Molecules ◽  
Wide Range ◽  
Anti Hiv ◽  
Structure And Activity

: Triterpenes are a wide and important group of compounds that have several promising pharmacological properties, such as hepatoprotective, anti-inflammatory, anti-HIV, antioxidant, or anticancer activities. Such potent substances can be successfully incorporated in more complex chemical systems e.g. codrugs or pro-drugs that have better pharmacological profile. The codrug is connected with a drug formation pathway to chemically cohere at least two drug molecules to improve positive therapeutic efficiency or decrease side effects. The codrug can be cleaved in the organism to generate effective compounds previously used as substrates. This article presents an overview of codrugs that consist of pentacyclic triterpene moiety that is chosen as a basic codrug moiety due to their wide range of vital activities and another drug molecule fragment. It was found that triterpenoid codrugs are characterized by a wide range of biological activities. However, most of them have anticancer potency.

scholarly journals A vanadium-based oxide-phosphate-pyrophosphate framework as a 4 V electrode material for K-ion batteries

2021 ◽  
Author(s):  
Mirai Ohara ◽  
A. Shahul Hameed ◽  
Kei Kubota ◽  
Akihiro Katogi ◽  
Kuniko Chihara ◽  
...  
Keyword(s):  
Energy Storage ◽  
Electrode Material ◽  
Large Scale ◽  
Electrode Materials ◽  
Electrical Energy ◽  
Positive Electrode ◽  
Electrical Energy Storage ◽  
Positive Electrode Materials

K-ion batteries (KIBs) are promising for large-scale electrical energy storage owing to the abundant resources and the electrochemical specificity of potassium. Among the positive electrode materials for KIBs, vanadium-based polyanionic...

scholarly journals Dipole-induced Ohmic contacts between monolayer Janus MoSSe and bulk metals

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Ning Zhao ◽  
Udo Schwingenschlögl
Keyword(s):  
First Principles ◽  
Ohmic Contacts ◽  
Electrode Materials ◽  
Electronic Device ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Fermi Level Pinning ◽  
Common Electrode ◽  
Two Sides ◽  
Metallic Electrodes

AbstractUtilizing a two-dimensional material in an electronic device as channel layer inevitably involves the formation of contacts with metallic electrodes. As these contacts can dramatically affect the behavior of the device, we study the electronic properties of monolayer Janus MoSSe in contact with different metallic electrodes by first-principles calculations, focusing on the differences in the characteristics of contacts with the two sides of MoSSe. In particular, we demonstrate that the Fermi level pinning is different for the two sides of MoSSe, with the magnitude resembling that of MoS2 or MoSe2, while both sides can form Ohmic contacts with common electrode materials without any further adaptation, which is an outstanding advantage over MoS2 and MoSe2.

Regioselective Functionalization of N-Fused Heteroaromatics via FeCl3-Catalyzed Nucleophilic Addition to Activated N-Heterocycles

Synthesis ◽  
2020 ◽  
Author(s):  
Ikyon Kim ◽  
Sung June Kim ◽  
Sunhee Lee
Keyword(s):  
Aromatic Compounds ◽  
Nucleophilic Addition ◽  
Chemical Space ◽  
Wide Range ◽  
Regioselective Functionalization

AbstractBroadening of nitrogen-fused heteroaromatic chemical space such as indolizine and pyrrolo[1,2-a]pyrazine was achieved via FeCl­3-catalyzed nucleophilic addition of these N-fused aromatic compounds to a wide range of azolinium systems generated in situ, leading to novel N-fused heteroaromatic scaffolds with dearomatized N-heterocyclic substituents regioselectively. Nucleophilic addition of indolizines and pyrrolo[1,2-a]pyrazines mainly occurred at the C1 position of the isoquinoliniums and at the C4 site of the quinoliniums.

scholarly journals Aluminum substitution for vanadium in the Na3V2(PO4)2F3 and Na3V2(PO4)2FO2 type materials

2019 ◽  
Vol 55 (78) ◽  
pp. 11719-11722 ◽  
Author(s):  
Jacob Olchowka ◽  
Long H. B. Nguyen ◽  
Thibault Broux ◽  
Paula Sanz Camacho ◽  
Emmanuel Petit ◽  
...  
Keyword(s):  
Structural Properties ◽  
Electrode Materials ◽  
Positive Electrode ◽  
Electrochemical Performances ◽  
Al Substitution ◽  
Aluminum Substitution ◽  
Positive Electrode Materials

Investigation of the effects of Al substitution for V on the structural properties and electrochemical performances for two of the most promising positive electrode materials for Na-ion batteries, Na3V2(PO4)2F3 and Na3V2(PO4)2FO2.

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