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Large amounts of volatile organic compounds (VOCs) are emitted into the atmosphere from both human and natural sources. A significant portion of VOCs would be oxidized via their reactions with atmospheric oxidants like OH, NO3, ozone, etc. The products of the oxidation reactions are often of low volatility and may condense to form secondary organic aerosols (SOA). To study the effect of VOC oxidation in aerosol formation, we are building an oxidation flow reactor system, which consists of (1) a 22‐l aluminum chamber, (2) an ozone source with an ozone detector, (3) a UV‐C (254 nm) lamp, (4) a photoionization detector to measure the effective VOC concentration, (5) various flow/concentration controlling apparatuses, and (6) a scanning mobility particle sizer to monitor the generated particles. Under the conditions of high UV and ozone levels, the oxidation process can be speeded up by orders of magnitude in this reactor. We hope to use this reactor: (i) to learn the "potential" mass of SOA that can be formed from a given VOC source like a traffic or industry site; (ii) to trace back the SOA source by utilizing the shortened reaction times; (iii) to learn the trends from VOC to SOA. [ABSTRACT FROM AUTHOR]

\nIMPACT STATEMENTData-driven material research for property prediction and material design using machine learning methods requires a large quantity, wide variety, and high-quality materials data. For battery materials, which are commonly polycrystalline, ceramics, and composites, multiscale data on substances, materials, and batteries are required. In this work, we develop a data network composed of three interlinked databases, from which we can obtain comprehensive data on substances such as crystal structures and electronic structures, data on materials such as chemical composition, structure, and properties, and data on batteries such as battery composition, operation conditions, and capacity. The data are extracted from research papers on solid electrolytes and cathode materials, selected by screening more than 330 thousand papers using natural language processing tools. Data extraction and curation are carried out by editors specialized in material science and trained in data standardization.We develop a comprehensive data network to accelerate battery material research, integrating multiscale data from three databases and 330,000+ papers using natural language processing and expert curation. [ABSTRACT FROM AUTHOR]

• The study employs topological data analysis (TDA) to identify and analyze atomic networks in amorphous materials, establishing meaningful connections to their thermal properties. • The observed enhancement in thermal conductivity is attributed to the presence of larger atomic rings. This enhancement is explained by the longer mean free paths (MFPs) and lower frequencies associated with these larger atomic rings. • The study emphasizes that changes in atomic networks, influenced by deposition temperature, play a pivotal role in determining the thermal conductivity of a-Ge. • This structural characterization technique is not limited to the specific material analyzed here but has broader applicability to various amorphous materials. Compared to crystalline materials, amorphous materials lack periodicity and exhibit distinct thermal and lattice vibration properties. Hence, analyzing atomic networks in the transmission electron microscopy (TEM) images of amorphous materials is challenging. In this study, we employ topological data analysis (TDA) and principal component analysis (PCA) to extract structural features from the TEM images of amorphous germanium (a-Ge) and analyze its atomic networks. Our findings demonstrate that the thermal conductivity of a-Ge is influenced by larger atomic rings with more vertices, which facilitates the heat transfer through longer atomic chains and results in a higher thermal conductivity. A comparison of the experimental and simulation data confirms the non-random nature of the atomic arrangements in a-Ge. We propose herein an approach that employs the TDA to identify and analyze the atomic networks in amorphous materials, establishing connections to their thermal properties. This study enhances our understanding of amorphous materials and paves a way for tailored material design and engineering to achieve the desired thermal properties. [ABSTRACT FROM AUTHOR]

We present a computational approach for identifying the important descriptors of the ionic conductivities of lithium solid electrolytes. Our approach discriminates the factors of both bulk and grain boundary conductivities, which have been rarely reported. The effects of the interrelated structural (e.g. grain size, phase), material (e.g. Li ratio), chemical (e.g. electronegativity, polarizability) and experimental (e.g. sintering temperature, synthesis method) properties on the bulk and grain boundary conductivities are investigated via machine learning. The data are trained using the bulk and grain boundary conductivities of Li solid conductors at room temperature. The important descriptors are elucidated by their feature importance and predictive performances, as determined by a nonlinear XGBoost algorithm: (i) the experimental descriptors of sintering conditions are significant for both bulk and grain boundary, (ii) the material descriptors of Li site occupancy and Li ratio are the prior descriptors for bulk, (iii) the density and unit cell volume are the prior structural descriptors while the polarizability and electronegativity are the prior chemical descriptors for grain boundary, (iv) the grain size provides physical insights such as the thermodynamic condition and should be considered for determining grain boundary conductance in solid polycrystalline ionic conductors. [ABSTRACT FROM AUTHOR]

Ni dopants typically exist as Ni 2+ oxidation state in metal oxides. We report that as Ni is co-doped with P in Ni(P):SnO 2 , P promotes Ni 2+ into Ni 3+ , which acts as acceptor and coverts n-type SnO 2 to p-type conduction. Significant hole concentration (4.5 × 10 18 cm −3 ) of p-type Ni(P):SnO 2 can be obtained. The chemical state of Ni 3+ in Ni(P):SnO 2 is verified by ultra-violet and x-ray photoelectron spectroscopy. With the developed p-Ni(P):SnO 2 , transparent p-Ni(P):SnO 2 /i-SnO 2 /n-ITO p-i-n structure was fabricated and characterized: low leakage-current (8.41 × 10 −5 A at −5 V), turn-on voltage (4.68 eV), good transmittance (85%), and small ideality-factor (1.73). [ABSTRACT FROM AUTHOR]

• ITR at metal/nonmetal interfaces subjected to bidirectional heat fluxes was studied. • A time domain thermoreflectance technique was used. • An avenue for the development of light-controlled thermal diodes is presented. Interfacial thermal resistance (ITR) at metal/nonmetal interfaces is a crucial issue affecting the efficiency of electronic devices. We investigated the ITR of Ni/Al 2 O 3 and W/Al 2 O 3 interfaces under the influence of bidirectional heat fluxes, with the heat flowing from the metal to the nonmetal and vice versa, using the time domain thermoreflectance technique. An asymmetric ITR was first experimentally observed such that the ITR was larger by a factor of 1.4–1.9 when the heat was applied from the nonmetal side, relative to the metal side. The additional interfacial electron–phonon couplings induced by the temperature difference between the hot electrons and phonons, which occur upon heating from the metal side, could be one of the plausible reasons causing the asymmetry. The thermal contribution of the interfacial electron–phonon coupling is found to be comparable with the phonon–phonon coupling. This new approach may allow us to elucidate thermal rectification at metal/nonmetal interfaces, thus leading to the development of light-controlled thermal diodes. [Display omitted] [ABSTRACT FROM AUTHOR]

• Small (<150 nm) highly mesoporous (porosity >50%) silicon nanoparticles developed. • Coated with N-doped carbon as high performance anode material for Li ion capacitor. • Glucose derived carbon nanospheres of 1,451 m2 g−1 as cathode for Li ion capacitor. • Achieve 210 Wh kg−1 at 0.32 kW kg−1 and maintain 70.1 Wh kg−1 at 36.1 kW kg−1. • Energy density retention of 89% after a 20,000 cycle operation at 8 A g−1. Highly mesoporous silicon nanoparticles of sizes less than 150 nm and porosity greater than 50% were successfully synthesized and composited with N-doped carbon (m-Si@NDC) as high performance anode materials for lithium ion based energy storage. The small size, large porosity, and composition with N-doped carbon coating layer of the highly mesoporous silicon nanoparticles offer much improved cycling volume expansion/shrinkage stability and overall conductivities, and create nano-sized reservoirs for lithium ions to enable local, fast lithiation/delithiation for much enhanced lithium ion based energy storage performances. The m-Si@NDC anode delivered a high specific capacity of 2,482 mAh g−1 at 0.2 A g−1 and maintained a decent specific capacity of 797 mAh g−1 at a high current density of 8 A g−1. The lithium ion capacitor, assembled by coupling the m-Si@NDC anode with a glucose derived carbon nanosphere (GCNS) cathode of an ultrahigh specific surface area of 1,451 m2 g−1, m-Si@NDC//GCNS, delivered a high energy density of 210 Wh kg−1 at a power density of 0.32 kW kg−1, and maintained a decent energy density of 70.1 Wh kg−1 at a high power density of 36.1 kW kg−1. The stability of m-Si@NDC//GCNS is also outstanding, exhibiting an energy density retention of 89% after a 20,000 cycle operation at a current density of 8 A g−1. The N-doped carbon coated small highly mesoporous silicon nanoparticles prove to be an outstanding nanostructure for anodes of lithium ion based energy storage. [ABSTRACT FROM AUTHOR]

• N-doped carbon nanobox is developed as anode material for lithium ion capacitor. • Nanobox serves as nano-reservoir for lithium ions for fast lithiation/delithiation. • Glucose derived carbon nanospheres of 1768 m2 g−1 are developed as cathodes. • Li ion capacitor delivers 78 Wh kg−1 at 0.31 kW kg−1 and 40 Wh kg−1 at 112 kW kg−1. • Li ion capacitor retains 138% capacity after 40,000 cycles at 10 A g−1. Lithium ion capacitors (LICs), lately evolved energy storage devices which integrate the merits of both lithium ion batteries (LIBs) and supercapacitors (SCs) for high energy and power densities, have attracted substantial research attention in recent years. Here, a Prussian blue analogue nanocube templating process was developed to produce N-doped carbon nanoboxes (N-CNB) as high performance anode materials for lithium ion based energy storage. The N-CNB exhibited high specific capacities and excellent rate capability and cycling performances as an anode. If paired with glucose derived carbon nanospheres (GCNS) cathodes, the N-CNB//GCNS LIC delivered a high energy density of 77.5 Wh kg−1 at the power density of 311.3 W kg−1 and maintained a decent energy density of 40.4 Wh kg−1 at a high power density of 112 kW kg−1. Its cycling performances were outstanding, reaching an ultrahigh, over 100%, capacity retention of 138% after a 40,000 cycle operation at 10 A g−1, attributable to the continuous electrochemical activation of the electrode materials. The success of the present LIC can be attributed to the advantageous nanobox structure in serving as nano-reservoirs for Li-ion to enable local, fast lithiation/delithiation and in buffering the volume expansion/shrinkage during lithiation/delithiation cycles. [ABSTRACT FROM AUTHOR]

The development of Bi 2 Te 3 thin films has huge potential in the pursuit of efficient thermoelectric micro/nanodevices due to their high Seebeck coefficient, high electrical conductivity and low thermal conductivity. The optimization of experimental parameters of Bi-Te thin films produced by co-evaporation will be investigated in this study. Co-evaporation is a low cost, easy-to-control process which can be used for high throughput and is scalable. We found that an optimal Te/Bi ratio of 1.5 with good thermoelectric properties can be directly synthesized by Bi and Bi 2 Te 3 co-evaporation. Compared to the conventional Bi/Te co-evaporation process, high temperature annealing or substrate heating is not necessary for the process mentioned in this paper, which is a desirable feature when using polymer-based substrates, organic/inorganic hybrid thermoelectric generators, and flexible devices since they have relatively low tolerance to heat. The optimized Bi 2 Te 3 thin films, which are mixed phases of Bi 2 Te 3 , Bi 3 Te 4 and Te, possess high carrier concentration (6.65 × 1020 cm−3), low electrical resistivity (3.17 × 10−3 Ωcm), and extremely low thermal conductivity (0.59 W/mK) at room temperature on a smooth surface (roughness <5.5 nm) and are achieved by adjusting the deposition rate of Bi and Bi 2 Te 3. The correlation between the structures of mixed phases, electrical and thermal properties will be discussed in detail. • The good thermoelectric properties can be achieved by Bi and Bi 2 Te 3 co-evaporation without high temperature annealing. • The optimization of Bi Te thin films are mixed phases with Te/Bi ratio of 1.5. • The Te/Bi ratio, composition of mixed phases and thickness affect the thermoelectric properties. • This simple and annealing-free method is attractive for the wearable devices which usually have lower melting point. [ABSTRACT FROM AUTHOR]

• CoS 2 @NC composite polyhedrons linked with MWCNTs as sulfur host. • Synergy of CoS 2 , porous N-doped C polyhedrons, and MWCNTs. • High capacity of 1133 mAh g−1 at 0.1C and decent capacity of 607 mAh g−1 at 2C. • Low capacity decay rate of 0.078% per cycle over 300 cycles at 1C. • Cycling stability improved via high N-doping and inter-linked rGO. Lithium sulfur batteries (LSBs) are regarded as one of the most promising energy storage devices because of their ultrahigh theoretical energy densities (2500 Wh kg−1), low cost, and environmental friendliness. Nevertheless, several detrimental drawbacks, including shuttling effects caused by soluble lithium polysulfides (LiPS), sluggish conversion kinetics between LiPS, and poor conductivities of sulfur, prevent commercialization of LSBs. To takle the above issues, MOF-derived cobalt disulfide/nitrogen-doped carbon (NC) composite polyhedrons linked with multi-walled carbon nanotubes (MWCNTs), CoS 2 @NC/MWCNT, were developed as an effective sulfur host for LSBs. It was fabricated through first in-situ growth of nanoporous ZIF-67 on surface treated MWCNTs, followed by carbonization and sulfurization. CoS 2 @NC/MWCNT combines the advantages of outstanding conductivities of MWCNTs, excellent chemical adsorption of NC and CoS 2 toward LiPS, and high catalytic efficiency of CoS 2 toward LiPS conversion, effectively addressing the shuttling, sluggish conversion, and low conductivity issues. The CoS 2 @NC/MWCNT electrode delivered a high specific capacity of 1133 mAh g−1 at 0.1C and maintained a decent specific capacity of 607 mAh g−1 at 2.0C. Its cycling stability is excellent, with a capacity retention rate of 77% after 300cycles at 1.0C, i.e., an average capacity decay rate of 0.078% per cycle. The cycling stability was further improved through increasing N-doping levels of the carbons for enhanced chemical adsorption toward LiPS and through incorporation of inter-linked reduced graphene oxide sheets as a physical barrier to reduce the diffusion loss of LiPS, achieving even smaller capacity decay rates of 0.066 and 0.064 % per cycle, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] The conductivity of AZO films degrades remarkably in high humidity ambient (90±5% relative humidity) at 60°C. [•] The high humidity depresses the formation of oxygen vacancies, and decreases the free carriers in the AZO films. [•] The electrical properties of AZO film can be stabilized by coating a Cr layer on the AZO film surface. [•] The Cr-coating layer can improve the AZO films electrical stability in the high partial oxygen-pressure annealing ambient. [ABSTRACT FROM AUTHOR]

Twinning is demonstrated to be an effective way of enhancing efficiencies of metallic catalysts toward electrolytic water splitting. Dendritic Cu possessing dense coherent nanotwin (NT) boundaries (NTCu‐5nm) is successfully prepared with an organic‐assisted electrodeposition at high pulse current densities. NT boundaries significantly improve electrocatalytic efficiencies and stability of NTCu‐5nm over nanocrystalline Cu (NCCu), reducing overpotentials at 10 mA cm−2 for the oxygen evolution reaction (OER) from 378 to 281 mV and from 235 to 88 mV for the hydrogen evolution reaction (HER), with a small chronoamperometric decay of 5% after 100 h continuous overall water splitting at an ultrahigh initial current density of 500 mA cm−2, largely outperforming the large chronoamperometric decay of 27% for only 1 h operation of the NCCu//NCCu couple. The defective twin boundaries enable formation of active CuIIIO2− at low overpotentials, thus enhancing OER performance. The synergistic geometric and electronic effects induced by the twin boundaries result in shifts in Gibbs free energies of hydrogen adsorption (ΔGH) toward the apex of a volcano plot of exchange current density versus ΔGH, leading to the remarkable improvement in HER activity. [ABSTRACT FROM AUTHOR]

In this study, the graphene-modified Al foils are prepared to assemble lithium ion batteries (LIBs) through a three-step approach comprising: (1) deposition of the polyamic acid (PAA) on the Al substrate; (2) curing the PAA to form the polyimide (PI)-coated Al foils; (3) converting the PI into porous graphene by CO 2 laser irradiation. With integration of the PI derived graphene (PDG) in the LIBs, the inserted PDG layer can enhance the adhesion and interface resistance between the active layer and Al electrode. The LiNi 0.5 Mn 1.5 O 4 (LNMO)//Li 4 Ti 5 O 12 (LTO) full cells with PDG layer are also fabricated to evaluate the effect of the modified layer on the cell performance. Compared to the pristine Al electrode, the modified current collector can improve the rate performance and reduce the temperature rise during the charge/discharge process leading to better cycling stability. [Display omitted] • Graphene-modified Al foils are prepared using laser writing technique. • Graphene-coated Al foils are used as a current collector in lithium ion battery. • Graphene layer can enhance the adhesion and conductivity. • The inserted graphene layer can enhance the rate and cycling performance. [ABSTRACT FROM AUTHOR]

Carbon-coated Li4Ti5O12 (LTO) has been prepared using polyimide (PI) as a carbon source via the thermal imidization of polyamic acid (PAA) followed by a carbonization process. In this study, the PI with different structures based on pyromellitic dianhydride (PMDA), 4,4′-oxydianiline (ODA), and p-phenylenediamine (p-PDA) moieties have been synthesized. The effect of the PI structure on the electrochemical performance of the carbon-coated LTO has been investigated. The results indicate that the molecular arrangement of PI can be improved when the rigid p-PDA units are introduced into the PI backbone. The carbons derived from the p-PDA-based PI show a more regular graphite structure with fewer defects and higher conductivity. As a result, the carbon-coated LTO exhibits a better rate performance with a discharge capacity of 137.5 mAh/g at 20 C, which is almost 1.5 times larger than that of bare LTO (94.4 mAh/g). [ABSTRACT FROM AUTHOR]

Twinning Enhances Efficiencies of Metallic Catalysts toward Electrolytic Water Splitting (Adv. Keywords: bifunctional electrocatalysts; hydrogen evolution reaction; nanotwin boundaries; oxygen evolution reaction; water splitting EN bifunctional electrocatalysts hydrogen evolution reaction nanotwin boundaries oxygen evolution reaction water splitting 1 1 1 12/13/21 20211209 NES 211209 B Twinned Metallic Electrocatalysts b In article number 2101827, YongMan Choi, Shih-Yuan Lu, and co-workers demonstrate that twinning enhances the efficiency of metallic catalysts in electrolytic water splitting. Bifunctional electrocatalysts, hydrogen evolution reaction, nanotwin boundaries, oxygen evolution reaction, water splitting. [Extracted from the article]

Au nanocrystal decoration boosts electrocatalytic performances of Fe, Co, and Ni based trimetallic metal organic frameworks toward oxygen evolution reaction. • Gold nanocrystals decorated FeCoNi trimetallic MOFs exhibit high OER efficiencies. • Engineering electronic states of MOF with gold nanocrystal decoration. • Gold nanocrystals facilitate formation of active intermediates toward OER. • In situ XAS study reveals that Ni and Co are active metal centers toward OER. • Fe plays a supporting role to help Ni acquire high valence states for OER. Electronic states of active sites of catalysts play a key role in determining electrocatalytic performances. Engineering electronic states through decoration of functional entities is an effective way to advance catalyst design. In this work, Au nanocrystal decorated Fe, Co, and Ni based trimetallic metal organic frameworks (MOFs) (termed Au/(FCN)MOFs), grown in-situ on nickel plates (NP), are developed as high performance oxygen evolution reaction (OER) electrocatalysts. At optimal Au nanocrystal decoration, the Au/(FCN)MOF/NP electrode achieves significantly improved OER performances over the (FCN)MOF/NP electrode, lowering η 10 and η 500 from 242 and 340 mV to 216 and 290 mV, respectively, Tafel slope from 42.1 to 31.7 mV dec−1, and current density decay from 6 to 5% after 50 h operations at an initial current density of 160 mA cm-2. The enhancement is attributed to the significantly elevated oxidation states of Fe, Co, and Ni, induced by decoration of the Au nanocrystals of high electronegativity, as evidenced with high-resolution X-ray photoelectron spectroscopy and in-situ Raman spectroscopy studies. Furthermore, the main active metal centers are identified with in-situ X-ray absorption spectroscopy study to be Ni and Co, with Fe playing a supporting role to help Ni acquire high valence states to realize enhanced OER activities. [ABSTRACT FROM AUTHOR]