Mechanism Of Incorporation Research Articles

High Efficiency Cu2ZnSn(S,Se)4 Solar Cells with Shallow LiZn Acceptor Defects Enabled by Solution‐Based Li Post‐Deposition Treatment

AbstractLithium incorporation in kesterite Cu2ZnSn(S,Se)4 (CZTSSe) materials has been experimentally proven effective in improving electronic quality for application in photovoltaic devices. Herein, a feasible and effective solution‐based lithium post‐deposition treatment (PDT), enabling further efficiency improvement on the high‐performance baseline is reported and the dominant mechanism for this improvement is proposed. In this way, lithium is uniformly incorporated into grain interiors (GIs) without segregation at grain boundaries (GBs), which can occupy the Zn sites with a high solubility in the CZTSSe matrix, producing high density of LiZn antisites with shallower acceptor levels than the intrinsic dominant defect (CuZn antisites). As a result, CZTSSe absorber with better p‐type doping is obtained, leading to a pronounced enhancement in fill factor and a corresponding gain in open‐circuit voltage and short‐circuit current and consequently a significant efficiency boost from 9.3% to 10.7%. This work provides a feasible alternative alkali‐PDT treatment for chalcogenide semiconductors and promotes a better understanding of the mechanism of Li incorporation in kesterite materials.

Особенности солюбилизирующего действия амфифильных соединений при обессмоливании целлюлозы

The necessity to improve the existing technology of pulp deresination, in particular, to reduce the surfactants consumption and decrease the environmental load, led to a combination of existing methods of resin removal with the use of enzymatic treatment. The basis of the pulp deresination mechanism by amphiphilic compounds is the solubilization of resinous substances. Thus, the establishment of the patterns of this process and its control predetermines the success of implementation of the selected technology. The features of solubilization of triolein and rosin in the lipase-based systems of individual nonionic surfactants, the enzyme, as well as their synergistic mixtures with the determination of solubilization capacities of micelles and the possible mechanism of solubilizate incorporation into them were studied using spectrophotometry, pH measurement and dynamic light scattering. It was found that synthamide-5 has a low deresination capability in spite of the high solubilization capacity of its micelles and the production of aggregates with a hydrodynamic radius up to 98 nm after diffusion of rosin into them. It is likely that compact micellar structures with a developed surface, which are implemented in mixed systems of amphiphilic compounds, including the presence of synthamide-5 in them, are more preferable for successful deresination of pulp semi-finished products. The addition of lipase leads to an increased solubilization capacity of mixed aggregates and an increase in the intensity of solubilizate molecules incorporation. Thus, depending on the nature of the amphiphilic compound, there is a different mechanism for solubilizate incorporation into micelles. Determination of the size of associates in mixed systems showed the absence of enzyme denaturation, which predicts the successful application of such cooperative systems for deresination of fiber semi-finished products. It is found that the solubilizing capability of the studied systems on resin modeling objects correlates with their deresination capability with respect to different fiber semi-finished products.

Mechanism of Incorporation of Zirconium into BiVO4 Visible-Light Photocatalyst

Monoclinic BiVO4 is a promising material for realizing low-cost visible-light water splitting. Here, we report the incorporation mechanism of Zr into solution-processed BiVO4. Characterization of t...

Internal stress-induced recrystallization and diffusive transport in CaTiO3-PbTiO3 solid solutions: A new transport mechanism in geomaterials and its implications for thermobarometry, geochronology, and geospeedometry

AbstractWe conducted a series of high-temperature experiments where single crystals of CaTiO3 were embedded in PbTiO3 powder for durations of 4 to 502 h at temperatures between 753 and 1207 °C. Combined with results from a previous study (Beyer et al. 2019), these experiments allow us to explore the influence of chemical potential gradients on the mechanisms of incorporation of Pb in CaTiO3. Unlike in the previous study where Pb diffused into CaTiO3, here we find that the rims of the CaTiO3 crystals recrystallize to form a polycrystalline aggregate of [PbxCa(1–x)]TiO3 solid solutions. The width of the recrystallized front increases with run duration, and the contact to the single crystal becomes progressively wavy. The concentration of Pb decreases within the recrystallized front toward the interior of the single crystal, and the newly formed crystals are of different chemical compositions and orientations and are themselves chemically zoned. There is a discontinuous jump in Pb-concentration at the contact of the recrystallized front with the single crystal (termed “the migrating interface”). The development of chemical concentration gradients, combined with the fact that the width of the front grows as the square-root of time indicates a role of diffusion in the process; the formation of new crystals with different composition and no orientation relation to the precursor, and the jump in concentration at the boundary between the newly formed crystals and the single crystal indicates a dissolution-precipitation type process. Thus, this is a novel mechanism where diffusion, as well as dissolution-precipitation (in the sense that the structure of the single crystal is destroyed and replaced by new crystals), occurs simultaneously in a coupled manner and neither is rate-determining. The observations in this experimental study provide several insights into the mechanisms of chemical transformation in such non-metallic materials: (1) chemical differences can trigger mechanical deformation, which in turn can control chemical fluxes; (2) newly formed crystals, even at the high temperatures of the experiments, evolve continuously in chemistry and are not of an equilibrium composition; (3) the activation energy of the overall process (~70 kJ/mol) is lower than that for diffusion and provides a more effective means of chemical transformation, even though diffusion plays a central role in the process; and (4) it underscores the role of surface/interface free energy in the evolution of the transformation process. These results have important consequences for the reading of the petrological and geochemical signatures of the rock record—notably, in addition to knowing when a phase becomes chemically stable, it is also important to know when a particular crystal of the phase begins to exist. Some possible implications for thermobarometry, isotopic dating, and geospeedometry/diffusion chronometry are discussed.

Development of vanadium impregnated flat absorber composite PEO coating on AA6061 alloy

Abstract The formation of black plasma electrolytic oxidation (PEO) coating on aluminium alloy using vanadyl sulphate as additive in a silicate-based electrolyte is investigated. A brief discussion on the mechanism of incorporation of vanadium in PEO coating starting with a cationic species of vanadium (i.e., VO2+) in solution is attempted. The coating formation with respect to morphology and composition is systematically studied as a function of process time. With increase in process time, incorporation of vanadium ions in the coating increases and the formation of black colour is attributed to the presence of V3+ and V4+ species in the coating. A 55 ± 5 μm thick flat absorber black coating with high solar absorptance (0.92) and high infrared emittance (0.88) is obtained with a process time of 10 min.

Chemical Bath Deposition of ZnO Nanowires Using Copper Nitrate as an Additive for Compensating Doping.

The controlled incorporation of dopants like copper into ZnO nanowires (NWs) grown by chemical bath deposition (CBD) is still challenging despite its critical importance for the development of piezoelectric devices. In this context, the effects of the addition of copper nitrate during the CBD of ZnO NWs grown on Au seed layers are investigated in detail, where zinc nitrate and hexamethylenetetramine are used as standard chemical precursors and ammonia as an additive to tune the pH. By combining thermodynamic simulations with chemical and structural analyses, we show that copper oxide nanocrystals simultaneously form with ZnO NWs during the CBD process in the low-pH region associated with large supersaturation of Cu species. The Cu(II) and Zn(II) speciation diagrams reveal that both species show very similar behaviors, as they predominantly form either X2+ ions (with X = Cu or Zn) or X(NH3)42+ ion complexes, depending on the pH value. Owing to their similar ionic structures, Cu2+ and Cu(NH3)42+ ions preferentially formed in the low- and high-pH regions, respectively, are able to compete with the corresponding Zn2+ and Zn(NH3)42+ ions to adsorb on the c-plane top facets of ZnO NWs despite repulsive electrostatic interactions, yielding the significant incorporation of Cu. At the highest pH value, additional attractive electrostatic interactions between the Cu(NH3)42+ ion complexes and negatively charged c-plane top facets further enhance the incorporation of Cu into ZnO NWs. The present findings provide a deep insight into the physicochemical processes at work during the CBD of ZnO NWs following the addition of copper nitrate, as well as a detailed analysis of the incorporation mechanisms of Cu into ZnO NWs, which are considered beyond the only electrostatic forces usually driving the incorporation of dopants such as Al and Ga.

Improving Ti Incorporation into the BEA Framework by Employing Ethoxylated Chlorotitanate as Ti Precursor: Postsynthesis, Characterization, and Incorporation Mechanism

The liquid–solid postsynthetic method is commonly used in the preparation of metal-containing zeolites, for example, Ti-β (BEA) zeolite. This paper reports a facile and Ti incorporation improved li...

Biomonitoring and Sourcing Toxic Elements Using Vascular Epiphytes of the Tillandsia Genus in the Mining Region of Taxco de Alarcón, Guerrero, Southern Mexico

The concentration of As, Pb, Cd, Zn, Fe, Mn, and Cu and the Sr and Pb isotopic compositions were determined in four species of the vascular epiphyte Tillandsia (T. caput medusae, T. ionantha, T. recurvata, and T. sp), to evaluate their capacity to biomonitor the air quality and the sources of lithogenic particles and toxic elements in a severely contaminated site from the mining region of Taxco de Alarcon, Guerrero (southern Mexico). With the exception of Cu, mean concentrations are typically higher in the contaminated site relative to a reference (uncontaminated) site, and the incrustation of metal-bearing particles (mainly PM10 and PM2.5) on leaves and roots seems to be the most significant mechanism of incorporation of these pollutants to plants. The Sr isotopic composition indicated that surrounding lithology is the main source of lithogenic particles, whereas statistical tools and Pb isotope ratios revealed a genetic link of toxic elements in epiphytes with Taxco ores and mining wastes, which confirm the capacity of the evaluated epiphytes to record local environmental conditions. The presence of abundant metal-bearing particles, particularly in the PM2.5, may represent a serious threat to the health of wild fauna, livestock, and humans in the zone. The study demonstrated that vascular epiphytes of the Tillandsia genus could be used as an efficient, low-cost, biotechnological tool for monitoring the air quality in severely contaminated polymetallic sites such as mining and smelting zones, as well as for sourcing lithogenic and metal-bearing particles.

Зависимость топологии эпитаксиальных слоев PbSnTe:In от концентрации In

The topology of the surface of epitaxial films of lead tin telluride solid solution, including those with the addition of indium (Pb1-xSnxTe:In), grown on single-crystal BaF2 (111) substrates and a CaF2/BaF2 buffer layer on Si (111) was studied by atomic force microscopy. It is shown that the characteristic statistical indicators of the relief are due to the peculiarities of film growth and the mechanism of incorporation of Indians, the excess content of which was registered on the surface ex situ by X-ray photoelectron spectroscopy.

Catalytic methane activation over La1−xSrxScO3−α proton-conducting oxide surface: A comprehensive study

The detailed investigation of the influence of strontium on the methane activation over the state-of-the-art proton-conducting oxide catalyst La1−xSrxScO3−α was carried out using a combination of the novel H/D isotopic exchange method, Raman Spectroscopy, 1H NMR and DFT studies in the temperature range 673 – 973 K, at 10 mbar of CH4 + H2 (95%+5%) mixture. It was found that methane activation occurs via the four parallel channels of the hydrogen adsorption and incorporation mechanism, followed by the formation of methane intermediates with different hydrogen content (CHx species). The dominant type of adsorbed intermediate is governed by the temperature and the surface defect structure, which is in close correlation with the strontium content. The increase of strontium content in La1−xSrxScO3−α drastically increases the catalytic activity due to the surface modification with oxygen deficiencies in the ScO6 octahedron, and stabilisation of the CHx species with a low amount of hydrogen.

Complementation of Splicing Activity by a Galectin-3 - U1 snRNP Complex on Beads.

Classic depletion-reconstitution experiments indicate that galectin-3 is a required splicing factor in nuclear extracts. The mechanism of incorporation of galectin-3 into the splicing pathway is addressed in this paper. Sedimentation of HeLa cell nuclear extracts on 12%-32% glycerol gradients yields fractions enriched in an endogenous ~10S particle that contains galectin-3 and U1 snRNP. We now describe a protocol to deplete nuclear extracts of U1 snRNP with concomitant loss of splicing activity. Splicing activity in the U1-depleted extract can be reconstituted by the galectin-3 - U1 snRNP particle trapped on agarose beads covalently coupled with anti-galectin-3 antibodies. The results indicate that the galectin-3 - U1 snRNP - pre-mRNA ternary complex is a functional E complex leading to intermediates and products of the splicing reaction and that galectin-3 enters the splicing pathway through its association with U1 snRNP. The scheme of using complexes affinity- or immuno-selected on beads to reconstitute splicing activity in extracts depleted of a specific splicing factor may be generally applicable to other systems.

Flow Electrolyzer Mass Spectrometry with a Gas-Diffusion Electrode Design.

Operando mass spectrometry is a powerful technique to probe reaction intermediates near the surface of catalyst in electrochemical systems. For electrochemical reactions involving gas reactants, conventional operando mass spectrometry struggles in detecting reaction intermediates because the batch-type electrochemical reactor can only handle a very limited current density due to the low solubility of gas reactant(s). Herein, we developed a new technique, namely flow electrolyzer mass spectrometry (FEMS), by incorporating a gas-diffusion electrode design, which enables the detection of reactive volatile or gaseous species at high operating current densities (>100 mA cm-2 ). We investigated the electrochemical carbon monoxide reduction reaction (eCORR) on polycrystalline copper and elucidated the oxygen incorporation mechanism in the acetaldehyde formation. Combining FEMS and isotopic labelling, we showed that the oxygen in the as-formed acetaldehyde intermediate originates from the reactant CO, while ethanol and n-propanol contained mainly solvent oxygen. The observation provides direct experimental evidence of an isotopic scrambling mechanism.

Flow Electrolyzer Mass Spectrometry with a Gas‐Diffusion Electrode Design

AbstractOperando mass spectrometry is a powerful technique to probe reaction intermediates near the surface of catalyst in electrochemical systems. For electrochemical reactions involving gas reactants, conventional operando mass spectrometry struggles in detecting reaction intermediates because the batch‐type electrochemical reactor can only handle a very limited current density due to the low solubility of gas reactant(s). Herein, we developed a new technique, namely flow electrolyzer mass spectrometry (FEMS), by incorporating a gas‐diffusion electrode design, which enables the detection of reactive volatile or gaseous species at high operating current densities (>100 mA cm−2). We investigated the electrochemical carbon monoxide reduction reaction (eCORR) on polycrystalline copper and elucidated the oxygen incorporation mechanism in the acetaldehyde formation. Combining FEMS and isotopic labelling, we showed that the oxygen in the as‐formed acetaldehyde intermediate originates from the reactant CO, while ethanol and n‐propanol contained mainly solvent oxygen. The observation provides direct experimental evidence of an isotopic scrambling mechanism.

Neuron-glia: understanding cellular copper homeostasis, its cross-talk and their contribution towards neurodegenerative diseases.

Over the years, the mechanism of copper homeostasis in various organ systems has gained importance. This is owing to the involvement of copper in a wide range of genetic disorders, most of them involving neurological symptoms. This highlights the importance of copper and its tight regulation in a complex organ system like the brain. It demands understanding the mechanism of copper acquisition and delivery to various cell types overcoming the limitation imposed by the blood brain barrier. The present review aims to investigate the existing work to understand the mechanism and complexity of cellular copper homeostasis in the two major cell types of the CNS - the neurons and the astrocytes. It investigates the mechanism of copper uptake, incorporation and export by these cell types. Furthermore, it brings forth the common as well as the exclusive aspects of neuronal and glial copper homeostasis including the studies from copper-based sensors. Glia act as a mediator of copper supply between the endothelium and the neurons. They possess all the qualifications of acting as a 'copper-sponge' for supply to the neurons. The neurons, on the other hand, require copper for various essential functions like incorporation as a cofactor for enzymes, synaptogenesis, axonal extension, inhibition of postsynaptic excitotoxicity, etc. Lastly, we also aim to understand the neuronal and glial pathology in various copper homeostasis disorders. The etiology of glial pathology and its contribution towards neuronal pathology and vice versa underlies the complexity of the neuropathology associated with the copper metabolism disorders.

A facile hydrolysis-controllable strategy for fast synthesis of Ti-MWW with steam-environment crystallization method

Numerous strategies have been developing to synthesis the Ti-MWW zeolites, but more effective synthesis process is still a significant challenge. In our study, with the synergy of PI and IPA (Isopropyl Alcohol) , the Ti-MWW zeolites with adjustable active sites were directly developed by titanium-silicon composite with homodisperse titanium species in the continuous circulation of SDA steam. The Ti-MWW achieved were flaky nanocrystal Ti-MWW with the size of 20–400 nm, and the mesopores with ca. 20 nm pore size and 0.76 cm3 g−1 total pore volumes were simultaneously created, and the crystallization period was decreased to 2 days for a comparison with 7–14 days required in conventional method. Furthermore, the catalytic tests showed that Ti-MWW exhibit a higher activity almost 7 times than Ti-MWW prepared by conventional dry–gel method in the liquid-phase epoxidation of 1-hexene with hydrogen peroxide due to the improved accessibility of the active sites inside the crystals and the number of active sites. The physicochemical properties were analyzed by XRD, SEM, BET, UV–Vis, FT-IR, ICP et al., and the mechanism for incorporation of titanium species into framework have been investigated in details. This facile and efficient synthetic strategy would considerably facilitate the preparation of zeolites with high catalytic performance in industrial production on a large-scale in the future.

Equation of State of hcp Fe‐C‐Si Alloys and the Effect of C Incorporation Mechanism on the Density of hcp Fe Alloys at 300 K

AbstractSi and C are cosmochemically abundant elements soluble in hcp Fe under pressure and temperature and could therefore be present in the Earth's inner core. While recent ab initio calculations suggest that the observed inner core density and velocities could be matched by an Fe‐C‐Si alloy, the combined effect of these two elements has only recently started to be investigated experimentally. We therefore carried out synchrotron X‐ray diffraction measurements of an hcp Fe‐C‐Si alloy with 4 at% C and 3 at% Si, up to ∼150 GPa. Density functional theory calculations were also performed to examine different incorporation mechanisms. These calculations suggest interstitial C to be more stable than substitutional C below ~350 GPa. In our calculations, we also find that the lowest‐energy incorporation mechanism in the investigated pressure range (60–400 GPa) is one where two C atoms occupy one atomic site; however, this is unlikely to be stable at high temperatures. Notably, substitutional C is observed to decrease the volume of the hcp Fe, while interstitial C increases it. This allows us to use experimental and theoretical equations of state to show unambiguously that C in the experimental hcp Fe‐C‐Si alloys is not substitutional, as is often assumed. This is crucial since assuming an incorrect incorporation mechanism in experiments leads to incorrect density determinations of ~4%, undermining attempts to estimate the concentration of C in the inner core. In addition, the agreement between our experiments and calculations supports Si and C as being light elements in the inner core.

Coprecipitation of metal ions into calcite: an estimation of partition coefficients based on field investigation

Trace elements (and their isotopes) in carbonates are commonly used to reconstruct paleoenvironment and paleoclimate. Understanding the processes and mechanisms of element incorporation into carbonates is thus crucial for using such geochemical parameters as paleoclimate proxies. In contrast to laboratory-based experimental results, the partitioning of trace metals between solid and solution phases in natural carbonate precipitation systems has rarely been reported. In this study, we investigated the partition coefficients of metal ions between solid and solution in the channel of the natural Baishuitai travertine system, Yunnan, China. Our results show that the partition coefficients of Li+, Na+, Mg2+, Sr2+ and Ba2+ are 1, consistent with the results found in previous experimental studies. Although the substitution for Ca2+ is likely the main uptake process of these metals into calcite, depending on their ionic radius and charge, trace elements may also be incorporated by adsorption or physical entrapment. Our study shows that unlike laboratory experiments performed under specific conditions, the partitioning of metals between two phases in the natural travertine system could be controlled by several, even multiple, environmental factors (e.g., carbonate deposition rate, temperature, and pH), which should be taken into account when using trace metals (and their isotopes) in carbonate archives as a paleoclimate proxy.

(Invited) MOCVD GaN-on-GaN Towards Vertical Power Devices & MOCVD Development of β-Ga2O3

Gallium nitride (GaN) has been considered as a promising candidate for power device applications due to the wide band gap (3.4 eV), high critical electric field (3 MV/cm) and high electron mobility (>1000 cm2/Vs). Baliga’s figure of merit (BFOM) of GaN is more than 500 times higher than silicon (Si) and more than three time higher than silicon carbide (SiC). Due to the availability of native GaN substrates, it is feasible to develop high performance GaN vertical power devices on low-defect GaN substrate. GaN-on-GaN vertical PN diode with record high VBR ~5 KV was reported [1], presenting the potential of GaN as a high-performance material for power devices. Compared with SiC, the performance of GaN vertical PN diodes is still limited by its high background doping in n-type drift layer at mid-1015 to low-1016 cm-3 range. Therefore, it is of great importance to study the sources and incorporation mechanisms of unintentionally doped background impurities in metal-organic chemical vapor deposition (MOCVD) GaN growth, to control the impurity incorporation, in order to maximize device performance for GaN based vertical power devices. This talk will discuss the dependence of MOCVD growth conditions on the impurity incorporations such as C, Si, O, H, and Fe. Quantitative SIMS and CV measurements are used for material characterization.Ultrawide bandgap (UWBG) gallium oxide (Ga2O3) with a band gap of 4.5-4.9 eV, represents an emerging semiconductor material with excellent chemical and thermal stability. The monoclinic β-phase Ga2O3 represents the thermodynamically stable crystal among the known five known phases (α, β, γ, d , ε). The breakdown field of β-Ga2O3 is estimated to be 6-8 MV/cm. These unique properties make β-Ga2O3 a promising candidate for high power electronic device and solar blind photodetector applications. Single crystal β-Ga2O3 substrates can be synthesized by scalable and low cost melting based growth techniques. MOCVD growth technique was used to develop high quality β-Ga2O3 thin films and its ternary alloy (AlxGa1-x)2O3. Control of background and n-type doping in β-Ga2O3 will be discussed. Record carrier mobilities of 194 cm2/V·s at room temperature and ~10,000 cm2/V·s at low temperature were measured for MOCVD β-Ga2O3 thin films [2]. MOCVD growth of β-AlGaO targeting for Al composition of > 40% will be discussed [3, 4]. Acknowledgement: The authors acknowledge the funding support from Advanced Research Projects Agency-Energy (ARPA-E) DE-AR0001036, U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Advanced Manufacturing Office, FY18/FY19 Lab Call, the Air Force Office of Scientific Research FA9550-18-1-0479 (AFOSR, Dr. Ali Sayir) and the National Science Foundation (1810041, 1755479). [1] H. Ohta, N. Asai, F. Horikiri, Y. Narita, T. Yoshida, and T. Mishima, Jpn. J. Appl. Phys. 58, SCCD03 (2019).[2] Z. Feng, A F M A. U. Bhuiyan, M. R. Karim, H. Zhao, Appl. Phys. Letts., 114, 250601, 2019.[3] A F M A. U. Bhuiyan, Z. Feng, J. M. Johnson, Z. Chen, H. -L. Huang, J. Hwang, H. Zhao, Appl. Phys. Lett., 115, 120602, 2019.[4] A F M A. U. Bhuiyan, Z. Feng, J. M. Johnson, H.-L. Huang, J. Sarker, M. Zhu, M. R. Karim, B. Mazumder, J. Hwang, and H. Zhao, APL Materials, 8, 031104, 2020.

Alkali Ion Storage and Migration in Carbonaceous Anode Materials – an Atomic Scale Study

Lithium-ion and post-lithium ion battery technologies are receiving increasing attention due to the need for a transition to a more sustainable energy economy. Apart from lithium ion batteries (LIBs), sodium ion batteries (NIBs) and potassium ion batteries (KIBs) are currently being investigated. Due to their low cost, natural abundance, and suitability for LIBs, NIBs, and KIBs, carbon-based anode materials, especially hard carbons, have gained scientific interest. The molecular structure of hard carbons is complex, and the atomistic understanding of metal ion storage and intercalation/de-intercalation during charge and discharge is limited. In this work we aim to shed light on these mechanisms through systematic computational modelling of LIB, NIB, and KIB carbon-based anode materials. Experimental studies have postulated that surface defects, planar, and curved pores can have a marked effect on metal storage in hard carbon.1–4 Density functional theory simulations of Li, Na, and K on different carbon motifs (defective graphene basal planes, planar graphitic layers, and curved pores) found in hard carbon anode materials were conducted to investigate their effect on the metal incorporation mechanism. Our calculations show that oxygen-, and nitrogen-containing defects are energetically favorable to form on single layer carbon fragment surfaces,5 and on curved morphologies. These defects were found to be highly beneficial for the initial metal storage, with Li, Na, and K adsorption energies greatly improved as compared to the non-defective carbon surface. Hence, it was deduced, as also suggested by experiment, that the presence of surface defects could indeed lead to increased metal storage. The effect of these defects on metal migration, which would influence the anode materials cycling properties, was investigated through nudged elastic band calculations, and showed that metal adsorption on surface defects can lead to capacity loss and irreversible metal storage. From defect formation energy calculations, it was seen that the defect expected to be present in the highest concentration on the carbon surface under equilibrium conditions is the 2OCNC defect, where three adjacent carbon have been substituted by two oxygen, and one nitrogen, respectively. This defect further has metal migration energy barriers many times higher than the corresponding ones at pristine surfaces, and would be highly detrimental for metal diffusion.5,6 We have also made efforts to model a more complex, disordered hard carbon structure. Metal intercalation energy as a function of carbon interlayer distance, and charge transfer of Na, Li, and K were calculated, based on nanoporous structures (expanded planar graphitic pores and cylindrical pores) identified by experimental analysis.1,2 Our simulations showed that metal incorporation and diffusion will be directly influenced by the pore shape and size, regardless of metal type. Planar graphitic pores were shown to play an important role in metal storage, with a direct impact observed on pore expansion, whereas curved morphologies contribute to rapid metal diffusion.2 In summary, the experimentally proposed metal charge/discharge mechanism of initial simultaneous metal storage on defects and intercalation in expanded pores, followed by pore filling was confirmed from atomic scale studies, showing the direct impact of carbon structure on the intercalation and storage properties of these metal ion battery anode materials.AcknowledgmentThe financial support from EPSRC (Engineering and Physical Sciences Council) under the grant number EP/M027066/1, and EP/R021554/2, is acknowledged.References 1 A.C.S. Jensen, E. Olsson, H. Au, H. Alptekin, Z. Yang, S. Cottrell, K. Yokoyama, Q. Cai, M.-M. Titirici, and A.J. Drew, J. Mater. Chem. A 8, 743 (2020). 2 E. Olsson, J. Cottom, H. Au, Z. Guo, A.C.S. Jensen, H. Alptekin, A.J. Drew, M.-M. Titirici, and Q. Cai, Adv. Funct. Mater. 1908209 (2020). 3 C. Matei Ghimbeu, J. Górka, V. Simone, L. Simonin, S. Martinet, and C. Vix-Guterl, Nano Energy 44, 327 (2018). 4 B. Zhang, C.M. Ghimbeu, C. Laberty, C. Vix-Guterl, and J.M. Tarascon, Adv. Energy Mater. 6, 1501588 (2016). 5 E. Olsson, G. Chai, M. Dove, and Q. Cai, Nanoscale 11, 5274 (2019). 6 E. Olsson, T. Hussain, A. Karton, and Q. Cai, Carbon N. Y. 163, 276 (2020).

The microstructure and mechanical properties of twinned copper-bismuth films obtained by DC electrodeposition

The engineering of grain boundaries (GB) by controlled twin boundaries introduction in the copper matrix is a promising way to achieve higher strength coupled with sufficient ductility and conductivity of copper materials being in a high demand for modern electronics. In the work, the oversized Bi atoms were introduced in the copper film using two step direct current (DC) electrodeposition technique. Via XRD, SEM and EBSD techniques it was shown that the fraction of twinned boundaries and the orientation of Cu and (100-x)Cu-xBi (x = 0.1, 0.5, 0.75 mol.%) films highly depend on the Bi(NiO3)3 concentration in the bath solution. Copper films possess both remarkably high hardness of 1.9 ± 0.2 GPa and Elastic modulus of 67 ± 7 GPa The 99.5Cu-0.5Bi (mol.%) film possesses the moderate hardness of 1 ± 0.1 GPa and Elastic modulus of 94 ± 9 GPa. Possible mechanisms of bismuth incorporation in the structure and its effect on mechanical properties of the copper based films are discussed.