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Bromine based redox flow batteries (RFBs) can provide sustainable energy storage due to the abundance of bromine. Such devices pair Br2/Br− at the positive electrode with complementary redox couples at the negative electrode. Due to the highly corrosive nature of bromine, electrode materials need to be corrosion resistant and durable. The positive electrode requires good electrochemical activity and reversibility for the Br2/Br− couple. Carbon materials enjoy the advantages of low cost, excellent electrical conductivity, chemical resistance, wide operational potential ranges, modifiable surface properties, and high surface area. Here carbon based materials for bromine electrodes are reviewed, with a focus on application in zinc‐bromine, hydrogen‐bromine, and polysulphide‐bromine RFB systems, aiming to provide an overview of carbon materials to be used for design and development of bromine electrodes with improved performance. Aspects deserving further R&D are highlighted. Carbon materials demonstrate suitable physical and chemical properties for applications in bromine based redox flow batteries (RFBs). This review summarizes the bromine/bromide reaction mechanisms taking place at the carbon electrode and provides an overview of different carbon based materials as the bromine electrodes. Built on this, its application in three RFB systems (e. g. zinc‐bromine, hydrogen‐bromine, and polysulphide‐bromine) have been examined in detail. A perspective highlights the importance of surface activation and treatment and aspects deserving further R&D.

Pollution from bromine and some of its related compounds is currently unregulated in soil from Russia and other countries, and tools for sound assessment of environmental impacts of bromine contamination are largely missing. Hence, assessing potential implications for humans and ecosystems of bromine soil contamination is urgently needed, which requires the combination of measured soil concentrations from environmental studies and quantified potential toxicity impacts. To address this need, we used data from an experimental study assessing bromine in soils (384 samples) of Tomsk oblast, Russia, starting from measured concentrations obtained by Instrumental Neutron Activation Analysis in an earlier study. From these data, we calculated the bromine mass in soils and used these as starting point to characterize related cumulative impacts on human health and ecosystems in the Tomsk region, using a global scientific consensus model for screening-level comparative toxicity characterization of chemical emissions. Results show that the combination of sampling methodology with toxicity characterization techniques presents a new approach to be used in environmental studies aimed at environmental assessment and analysis of a territory. Our results indicate that it is important to account for substance-specific chemical reaction pathways and transfer processes, as well as to consider region-specific environmental characteristics. Our approach will help complement environmental assessment results with environmental sustainability elements, to consider potential tradeoffs in impacts, related to soil pollution, in support of improved emission and pollution reduction strategies.

The development of energy storage systems (ESS) has become an important area of research due to the need to replace the use of fossil fuels with clean energy. Redox flow batteries (RFBs) provide interesting features, such as the ability to separate the power and battery capacity. This is because the electrolyte tank is located outside the electrochemical cell. Consequently, it is possible to design each battery according to different needs. In this context, zinc–bromine flow batteries (ZBFBs) have shown suitable properties such as raw material availability and low battery cost. To avoid the corrosion and toxicity caused by the free bromine (Br2) generated during the charging process, it is necessary to use bromine complexing agents (BCAs) capable of creating complexes. As an overview, the different BCAs used have been listed to compare their behavior when used in electrolytes in ZBFBs. In addition, the coulombic and energy efficiencies obtained have been compared.

Bromine and peroxidasin (an extracellular peroxidase) are essential for generating sulfilimine cross-links between a methionine and a hydroxylysine within collagen IV, a basement membrane protein. The sulfilimine cross-links increase the structural integrity of basement membranes. The formation of sulfilimine cross-links depends on the ability of peroxidasin to use bromide and hydrogen peroxide substrates to produce hypobromous acid (HOBr). Once a sulfilimine cross-link is created, bromide is released into the extracellular space and becomes available for reutilization. Whether the HOBr generated by peroxidasin is used very selectively for creating sulfilimine cross-links or whether it also causes oxidative damage to bystander molecules (e.g., generating bromotyrosine residues in basement membrane proteins) is unclear. To examine this issue, we used nanoscale secondary ion mass spectrometry (NanoSIMS) imaging to define the distribution of bromine in mammalian tissues. We observed striking enrichment of bromine (79Br, 81Br) in basement membranes of normal human and mouse kidneys. In peroxidasin knockout mice, bromine enrichment of basement membranes of kidneys was reduced by ∼85%. Proteomic studies revealed bromination of tyrosine-1485 in the NC1 domain of α2 collagen IV from kidneys of wild-type mice; the same tyrosine was brominated in collagen IV from human kidney. Bromination of tyrosine-1485 was reduced by >90% in kidneys of peroxidasin knockout mice. Thus, in addition to promoting sulfilimine cross-links in collagen IV, peroxidasin can also brominate a bystander tyrosine. Also, the fact that bromine enrichment is largely confined to basement membranes implies that peroxidasin activity is largely restricted to basement membranes in mammalian tissues.

Two consecutive cruises in the Weddell Sea, Antarctica, in winter 2013 provided the first direct observations of sea salt aerosol (SSA) production from blowing snow above sea ice, thereby validating a model hypothesis to account for winter time SSA maxima in the Antarctic. Blowing or drifting snow often leads to increases in SSA during and after storms. For the first time it is shown that snow on sea ice is depleted in sulfate relative to sodium with respect to seawater. Similar depletion in bulk aerosol sized ∼0.3–6 µm above sea ice provided the evidence that most sea salt originated from snow on sea ice and not the open ocean or leads, e.g. >90 % during the 8 June to 12 August 2013 period. A temporally very close association of snow and aerosol particle dynamics together with the long distance to the nearest open ocean further supports SSA originating from a local source. A mass budget estimate shows that snow on sea ice contains even at low salinity (<0.1 psu) more than enough sea salt to account for observed increases in atmospheric SSA during storms if released by sublimation. Furthermore, snow on sea ice and blowing snow showed no or small depletion of bromide relative to sodium with respect to seawater, whereas aerosol was enriched at 2 m and depleted at 29 m, suggesting that significant bromine loss takes place in the aerosol phase further aloft and that SSA from blowing snow is a source of atmospheric reactive bromine, an important ozone sink, even during winter darkness. The relative increase in aerosol concentrations with wind speed was much larger above sea ice than above the open ocean, highlighting the importance of a sea ice source in winter and early spring for the aerosol burden above sea ice. Comparison of absolute increases in aerosol concentrations during storms suggests that to a first order corresponding aerosol fluxes above sea ice can rival those above the open ocean depending on particle size. Evaluation of the current model for SSA production from blowing snow showed that the parameterizations used can generally be applied to snow on sea ice. Snow salinity, a sensitive model parameter, depends to a first order on snowpack depth and therefore was higher above first-year sea ice (FYI) than above multi-year sea ice (MYI). Shifts in the ratio of FYI and MYI over time are therefore expected to change the seasonal SSA source flux and contribute to the variability of SSA in ice cores, which represents both an opportunity and a challenge for the quantitative interpretation of sea salt in ice cores as a proxy for sea ice.

Maximizing the power conversion efficiency (PCE) of perovskite/silicon tandem solar cells that can exceed the Shockley-Queisser single-cell limit requires a high-performing, stable perovskite top cell with a wide bandgap. We developed a stable perovskite solar cell with a bandgap of ∼1.7 electron volts that retained more than 80% of its initial PCE of 20.7% after 1000 hours of continuous illumination. Anion engineering of phenethylammonium-based two-dimensional (2D) additives was critical for controlling the structural and electrical properties of the 2D passivation layers based on a lead iodide framework. The high PCE of 26.7% of a monolithic two-terminal wide-bandgap perovskite/silicon tandem solar cell was made possible by the ideal combination of spectral responses of the top and bottom cells.

Hybrid perovskite solar cells often use the more thermally stable formamidinium (FA) cation rather than methylammonium, but its larger size can create lattice distortion that results in an inactive yellow phase. Turren-Cruz et al. show that by using iodide instead of bromide as the anion (to create a redder bandgap) and an optical mix of cesium, rubidium, and FA cations, they can make solar cells with a stabilized efficiency of more than 20%. No heating steps above 100°C were needed to create the preferred black phase. Science , this issue p. 449 Avoidance of bromide anions and methylammonium cations allows optimal tuning of perovskite bandgaps. Currently, perovskite solar cells (PSCs) with high performances greater than 20% contain bromine (Br), causing a suboptimal bandgap, and the thermally unstable methylammonium (MA) molecule. Avoiding Br and especially MA can therefore result in more optimal bandgaps and stable perovskites. We show that inorganic cation tuning, using rubidium and cesium, enables highly crystalline formamidinium-based perovskites without Br or MA. On a conventional, planar device architecture, using polymeric interlayers at the electron- and hole-transporting interface, we demonstrate an efficiency of 20.35% (stabilized), one of the highest for MA-free perovskites, with a drastically improved stability reached without the stabilizing influence of mesoporous interlayers. The perovskite is not heated beyond 100°C. Going MA-free is a new direction for perovskites that are inherently stable and compatible with tandems or flexible substrates, which are the main routes commercializing PSCs.

In general, mixed cations and anions containing formamidinium (FA), methylammonium (MA), caesium, iodine, and bromine ions are used to stabilize the black α-phase of the FA-based lead triiodide (FAPbI₃) in perovskite solar cells. However, additives such as MA, caesium, and bromine widen its bandgap and reduce the thermal stability. We stabilized the α-FAPbI₃ phase by doping with methylenediammonium dichloride (MDACl₂) and achieved a certified short-circuit current density of between 26.1 and 26.7 milliamperes per square centimeter. With certified power conversion efficiencies (PCEs) of 23.7%, more than 90% of the initial efficiency was maintained after 600 hours of operation with maximum power point tracking under full sunlight illumination in ambient conditions including ultraviolet light. Unencapsulated devices retained more than 90% of their initial PCE even after annealing for 20 hours at 150°C in air and exhibited superior thermal and humidity stability over a control device in which FAPbI₃ was stabilized by MAPbBr₃.

Wide–band gap metal halide perovskites are promising semiconductors to pair with silicon in tandem solar cells to pursue the goal of achieving power conversion efficiency (PCE) greater than 30% at low cost. However, wide–band gap perovskite solar cells have been fundamentally limited by photoinduced phase segregation and low open-circuit voltage. We report efficient 1.67–electron volt wide–band gap perovskite top cells using triple-halide alloys (chlorine, bromine, iodine) to tailor the band gap and stabilize the semiconductor under illumination. We show a factor of 2 increase in photocarrier lifetime and charge-carrier mobility that resulted from enhancing the solubility of chlorine by replacing some of the iodine with bromine to shrink the lattice parameter. We observed a suppression of light-induced phase segregation in films even at 100-sun illumination intensity and less than 4% degradation in semitransparent top cells after 1000 hours of maximum power point (MPP) operation at 60°C. By integrating these top cells with silicon bottom cells, we achieved a PCE of 27% in two-terminal monolithic tandems with an area of 1 square centimeter.

Halogen bonds have been identified in a series of ionic compounds involving bromonium and iodonium cations and several different anions, some also containing hypervalent atoms. The hypervalent bromine and iodine atoms in the examined compounds are found to have positive σ-holes on the extensions of their covalent bonds, while the hypervalent atoms in the anions have negative σ-holes. The positive σ-holes on the halogens of the studied halonium salts determine the linearity of the short contacts between the halogen and neutral or anionic electron donors, as usual in halogen bonds.