Polyimides as Promising Cathodes for Metal-Organic Batteries: A Comparison between Divalent (Ca2+, Mg2+) and Monovalent (Li+, Na+) Cations

Ca- and Mg-based batteries represent a more sustainable alternative to Li-ion batteries. However, multivalent cation technologies suffer from poor cation mass transport. In addition, the development of positive electrodes enabling reversible charge storage currently represents one of the major challenges. Organic positive electrodes, in addition to being the most sustainable and potentially low-cost candidates, compared with their inorganic counterparts, currently present the best electrochemical performances in Ca and Mg cells. Unfortunately, organic positive electrodes suffer from relatively low capacity retention upon cycling, the origin of which is not yet fully understood. Here, 1,4,5,8-naphthalenetetracarboxylic dianhydride-derived polyimide was tested in Li, Na, Mg, and Ca cells for the sake of comparison in terms of redox potential, gravimetric capacities, capacity retention, and rate capability. The redox mechanisms were also investigated by means of operando IR experiments, and a parameter affecting most figures of merit has been identified: the presence of contact ion-pairs in the electrolyte.Funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 715087) is gratefully acknowledged. ICMAB-CSIC members are grateful for funding through PTI+ TRANSENER+: “Alta Tecnología clave en la transición en el ciclo energético”, part of the CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094 and thank the Spanish Agencia Estatal de Investigación Severo Ochoa Programme for Centres of Excellence in R&D (CEX2019-000917-S).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Fundamentals of hydrogen storage in nanoporous materials

Physisorption of hydrogen in nanoporous materials offers an efficient and competitive alternative for hydrogen storage. At low temperatures (e.g. 77 K) and moderate pressures (below 100 bar) molecular H2 adsorbs reversibly, with very fast kinetics, at high density on the inner surfaces of materials such as zeolites, activated carbons and metal–organic frameworks (MOFs). This review, by experts of Task 40 ‘Energy Storage and Conversion based on Hydrogen’ of the Hydrogen Technology Collaboration Programme of the International Energy Agency, covers the fundamentals of H2 adsorption in nanoporous materials and assessment of their storage performance. The discussion includes recent work on H2 adsorption at both low temperature and high pressure, new findings on the assessment of the hydrogen storage performance of materials, the correlation of volumetric and gravimetric H2 storage capacities, usable capacity, and optimum operating temperature. The application of neutron scattering as an ideal tool for characterising H2 adsorption is summarised and state-of-the-art computational methods, such as machine learning, are considered for the discovery of new MOFs for H2 storage applications, as well as the modelling of flexible porous networks for optimised H2 delivery. The discussion focuses moreover on additional important issues, such as sustainable materials synthesis and improved reproducibility of experimental H2 adsorption isotherm data by interlaboratory exercises and reference materials

Materials for hydrogen-based energy storage - past, recent progress and future outlook

Globally, the accelerating use of renewable energy sources, enabled by increased efficiencies and reduced costs, and driven by the need to mitigate the effects of climate change, has significantly increased research in the areas of renewable energy production, storage, distribution and end-use. Central to this discussion is the use of hydrogen, as a clean, efficient energy vector for energy storage. This review, by experts of Task 32, “Hydrogen-based Energy Storage” of the International Energy Agency, Hydrogen TCP, reports on the development over the last 6 years of hydrogen storage materials, methods and techniques, including electrochemical and thermal storage systems. An overview is given on the background to the various methods, the current state of development and the future prospects. The following areas are covered; porous materials, liquid hydrogen carriers, complex hydrides, intermetallic hydrides, electrochemical storage of energy, thermal energy storage, hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage

THEORETICAL INVESTIGATION OF LOWSYMETRY SEMICONDUCTOR SYSTEMS IN THE REAL SPACE

WITH THE USE A "4-BODY" CLASSICAL POTENTIAL THAT WE HAD DEVELOP FOR SI, AND WITH MOLECULAR DYNAMICS AND MONTE-CARLO SIMULATIONS, WE REPRODUCT THE GROUND STATE GEOMETRIES FOR SI CLUSTERS (SIN:N=5-18), WE MANAGE TO SEPARATE ENERGETICALLY THE "TOP" AND "HOLLOW" STRUCTURES IN 3X3 RECONSTRUCTION OF SI(1,1,1) SURFACE, AND FINALLY, THE MODEL AMORPHOUS SILICON AND FIND REALISTIC PROPERTIES. WITH THE USE OF CLUSTER METHOD,WE SEPARATE THE "DANGLING-BOND" AND "HOATING-BOND" DEFECTS OF A-SI AND WE INVESTIGATE THEM WITH HARTHREE-FOCK METHOD. WE INVESTIGATE "AB-INITIO" FIFTH-ATOMIC AND SIX-ATOMIC SI-C CLUSTER AND WE FOUND THEIR BONDIND AND ELECTRONIC PROPERTIES. IN ADITTION WE FOUND SOME "BUILDING-UP" PRINCIPLES FOR THOSE CLUSTERS. FINALLY WITH THE USE OF DENSITY FUNCTIONAL THEORY WE INVESTIGATE GEY CLUSTER AND WE FOUND THE RELATION OF SI AND C CLUSTERS.ΜΕ ΤΗΝ ΚΑΤΑΣΚΕΥΗ ΕΝΟΣ ΚΛΑΣΣΙΚΟΥ ΔΥΝΑΜΙΚΟΥ ΤΕΣΣΑΡΩΝ ΣΩΜΑΤΩΝ ΓΙΑ ΤΟ ΠΥΡΙΤΙΟ ΚΑΙ ΜΕ ΤΗ ΧΡΗΣΗ ΜΕΘΟΔΩΝ ΜΟΡΙΑΚΗΣ ΔΥΝΑΜΙΚΗΣ ΚΑΙ MONTE-CARLO ΑΝΑΠΑΡΑΓΑΜΕ ΓΕΩΜΕΤΡΙΕΣ ΣΥΣΣΩΜΑΤΩΜΑΤΩΝ ΠΥΡΙΤΙΟΥ (SIN:N=5+8), ΕΠΙΤΥΧΑΜΕ ΝΑ ΔΙΑΧΩΡΙΣΟΥΜΕ ΕΝΕΡΓΕΙΑΚΑ ΤΙΣ ΔΟΜΕΣ "TOP" ΚΑΙ "HOLLOW" ΣΤΗΝ ΤΕΤΡ. ΡΙΖΑ 3Χ ΤΕΤΡ. ΡΙΖΑ 3 ΑΝΑΔΟΜΗΣΗ ΤΗΣ (1,1,1) ΕΠΙΦΑΝΕΙΑΣ ΤΟΥ ΠΥΡΙΤΙΟΥ ΚΑΙ ΤΕΛΟΣ ΚΑΤΑΣΚΕΥΑΣΑΜΕ ΕΝΑ ΜΟΝΤΕΛΟ ΑΜΟΡΦΟΥ ΠΥΡΙΤΙΟΥΤΟ ΟΠΟΙΟ ΕΔΩΣΕ ΡΕΑΛΙΣΤΙΚΕΣ ΙΔΙΟΤΗΤΕΣ. ΜΕ ΤΗΝ ΜΕΘΟΔΟ ΤΩΝ ΣΥΣΣΩΜΑΤΩΜΑΤΩΝ ΑΠΟΜΟΝΩΣΑΜΕ ΤΙΣ "DANGLING-BOND" ΚΑΙ "FLOATING-BOND" ΑΤΕΛΕΙΕΣ ΤΟΥ A-SI ΚΑΙ ΤΙΣ ΜΕΛΕΤΗΣΑΜΕ ΜΕ ΤΗΝ ΜΕΘΟΔΟ HARTREE-FECK. ΜΕ ΜΕΘΟΔΟΥΣ "ΑΠΟ ΠΡΩΤΕΣ ΑΡΧΕΣ" ΒΡΗΚΑΜΕ ΤΙΣ ΔΟΜΙΚΕΣ ΚΑΙ ΗΛΕΚΤΡΟΝΙΚΕΣ ΙΔΙΟΤΗΤΕΣ ΤΩΝ ΠΕΝΤΑΤΟΜΙΚΩΝ ΚΑΙ ΕΞΑΤΟΜΙΚΩΝ ΣΥΣΣΩΜΑΤΩΜΑΤΩΝ ΠΥΡΙΤΙΟΥ-ΑΝΘΡΑΚΑ ΚΑΘΩΣ ΚΑΙ ΜΕΡΙΚΟΥΣ "ΚΑΝΟΝΕΣ ΔΟΜΙΣΗΣ" ΓΙΑ ΤΑ ΣΥΣΣΩΜΑΤΩΜΑΤΑ ΑΥΤΑ. ΤΕΛΟΣ ΜΕ ΤΗ ΧΡΗΣΗ ΤΗΣ ΘΕΩΡΙΑΣ ΣΥΝΑΡΤΗΣΙΑΚΟΥ ΠΥΚΝΟΤΗΤΑΣ ΜΕΛΕΤΗΣΑΜΕ ΤΟ ΣΥΣΣΩΜΑΤΩΜΑ GE4 ΚΑΙ ΠΙΣΤΟΠΟΙΗΣΑΜΕ ΤΗ ΣΥΓΓΕΝΕΙΑ ΤΩΝ ΣΥΣΣΩΜΑΤΩΜΑΤΩΝ ΠΥΡΙΤΙΟΥ ΚΑΙ ΓΕΡΜΑΝΙΟΥ

Atomic Hydrogen Diffusion on Doped and Chemically Modified Graphene

To explore hydrogen mobility on graphene, density functional calculations are used to determine the magnitude of binding energy versus the diffusion barrier for graphene, considering the effects of hole and electron doping, B and N substitutional dopants, and oxygen heteroatoms. Although C-H binding energy and the barrier for chemical diffusion are not correlated, the binding energy of H in the lowest energy site on top of a C atom correlates with the binding energy of H over a bridge C-C bond, which is the transition state for chemical diffusion. Using this framework, we demonstrate that both B substitutionally doped graphene and hydoxylated graphene have the potential to simultaneously meet thermodynamic and kinetic constraints for reversible room-temperature hydrogenation. The constraints demonstrate that reversible room-temperature hydrogenation is possible only when H diffuses in a chemically bound state

Enhancing NO Uptake in Metal-Organic Frameworks via Linker Functionalization. A Multi-Scale Theoretical Study

In the present work, ab initio calculations and Monte Carlo simulations were combined to investigate the effect of linker functionalization on nitric oxide (NO)’s storage ability of metal–organic frameworks (MOFs). The binding energy (BE) of nitric oxide with a set of forty-two strategically selected, functionalized benzenes was investigated using Density Functional Theory calculations at the RI-DSD-BLYP/def2-TZVPP level of theory. It was found that most of the functional groups (FGs) increased the interaction strength compared to benzene. Phenyl hydrogen sulfate (–OSO3H) was the most promising among the set of ligands, with an enhancement of 150%. The organic linker of IRMOF-8 was modified with the three top-performing functional groups (–OSO3H, –OPO3H2, –SO3H). Their ability for NO adsorption was investigated using Grand Canonical Monte Carlo (GCMC) simulations at an ambient temperature and a wide pressure range. The results showed great enhancement in NO uptake constituting the above-mentioned FGs, suggesting them to be promising modification candidates in a plethora of porous materials

Enhancing of CO Uptake in Metal-Organic Frameworks by Linker Functionalization: A Multi-Scale Theoretical Study

In the present work, the interaction strength of Carbon Monoxide (CO) with a set of forty-two, strategically selected, functionalized benzenes was calculated. Our ab initio calculations at the MP2/6-311++G** level of theory reveal that phenyl hydrogen sulfate (-OSO3H) showed the highest interaction with CO (−19.5 kJ/mol), which was approximately three times stronger compared with the unfunctionalized benzene (−5.3 kJ/mol). Moreover, the three top-performing functional groups (-OSO3H, -OPO3H2, -SO3H) were selected to modify the organic linker of IRMOF-8 and test their ability to capture CO at 298 K for a wide pressure range. Our Grand Canonical Monte Carlo (GCMC) simulations showed a significant increase in the CO uptake in the functionalized MOFs compared with the parent IRMOF-8. It is distinctive that for the volumetric uptake, a 60× increase was observed at 1 bar and 2× was observed at 100 bar. The proposed functionalization strategy can be applied for improving the CO uptake performance not only in MOFs but also in various other porous materials

Enhancing NO Uptake in Metal-Organic Frameworks via Linker Functionalization. A Multi-Scale Theoretical Study

In the present work, ab initio calculations and Monte Carlo simulations were combined to investigate the effect of linker functionalization on nitric oxide (NO)’s storage ability of metal–organic frameworks (MOFs). The binding energy (BE) of nitric oxide with a set of forty-two strategically selected, functionalized benzenes was investigated using Density Functional Theory calculations at the RI-DSD-BLYP/def2-TZVPP level of theory. It was found that most of the functional groups (FGs) increased the interaction strength compared to benzene. Phenyl hydrogen sulfate (–OSO3H) was the most promising among the set of ligands, with an enhancement of 150%. The organic linker of IRMOF-8 was modified with the three top-performing functional groups (–OSO3H, –OPO3H2, –SO3H). Their ability for NO adsorption was investigated using Grand Canonical Monte Carlo (GCMC) simulations at an ambient temperature and a wide pressure range. The results showed great enhancement in NO uptake constituting the above-mentioned FGs, suggesting them to be promising modification candidates in a plethora of porous materials