Search

Sodium‐ion technology is a reliable alternative to lithium‐ion for large‐scale energy storage because of the abundance of sodium sources and related low cost. In this work, we report about a simple fabrication of self‐standing electrodes based on electrospun carbon nanofiber (CNF) loaded with Na3V2(PO4)3 with NASICON framework, which is a promising cathode material that has shown good electrochemical performance when its electrical conductivity is enhanced by a conductive medium. The proposed method is simple, low cost, potentially scalable to fabricate and load cathode support with active materials. The electrochemical tests confirmed the stable cycling performances and the high C‐rate capability of the NVP/CNFs composites, with hundreds of cycles without major degradation of performances. Our work demonstrates that stable, self‐supported, long‐term performing NIB electrodes, ready to use without addition of any performance enhancer, can be obtained by using fast and cost‐efficient procedures suitable to be scaled‐up at an industrial level.

In article number 2100881, Nicolas H. Voelcker, Jessica E. Frith, Victor J. Cadarso, and co-workers demonstrate a novel approach to imprint micro and nanoscaled topographical features into conventional cell cultureware, facilitating its compatibility with standard biological techniques. This enables high-throughput screening to integrate the effects of surface topographies into unique cell specific responses and fate determination.

Thermal energy storage (TES) for a cooling plant is a crucial resource for load flexibility. Traditionally, simple, heuristic control approaches, such as the storage priority control which charges TES during the nighttime and discharges during the daytime, have been widely used in practice, and shown reasonable performance in the past benefiting both the grid and the end-users such as buildings and district energy systems. However, the increasing penetration of renewables changes the situation, exposing the grid to a growing duck curve, which encourages the consumption of more energy in the daytime, and volatile renewable generation which requires dynamic planning. The growing pressure of diminishing greenhouse gas emissions also increases the complexity of cooling TES plant operations as different control strategies may apply to optimize operations for energy cost or carbon emissions. This paper presents a model predictive control (MPC), site demonstration and evaluation results of optimal operation of a chiller plant, TES and behind-meter photovoltaics for a campus-level district cooling system. The MPC was formulated as a mixed-integer linear program for better numerical and control properties. Compared with baseline rule-based controls, the MPC results show reductions of the excess PV power by around 25%, of the greenhouse gas emission by 10%, and of peak electricity demand by 10%.

Reactions among minerals occur via solid-state diffusion or fluid-induced, interface-coupled dissolution-reprecipitation (ICDR). Both mechanisms can coexist under conditions where the rates of both processes are similar, depending mainly on the nature of the mineral, temperature, and fluid composition. To clarify the synergies between these reaction mechanisms, we investigated the replacement and recrystallization reactions of chalcopyrite in the presence of a 65Cu-enriched aqueous fluid. The replacement of chalcopyrite by secondary copper sulfides follows a paragenetic sequence, whereby chalcopyrite is initially replaced by covellite, and then by digenite, with some of the digenite replacing covellite in longer duration experiments. The replacement reactions proceed via ICDR along with solid-state diffusion of 65Cu from the fluid into product minerals, with both mechanisms occurring at similar rates. Over time, chalcopyrite is completely replaced, and the secondary copper sulfides attain isotopic equilibrium with the fluid. Depending on temperature, thermal history, and fluid-mineral ratio, the reaction products may preserve kinetic or equilibrium signatures. We have identified a new geochemical process of ‘porosity-aided recrystallization’, which may result in a re-equilibration or perturbation of mineral isotopic/trace element compositions due to exchanges between the mineral and fluid facilitated by extensive micro- to nano-scale porosity created by ICDR reactions. Porosity-aided recrystallization will affect any mineral-fluid system where mass transfers via solid-state diffusion and ICDR operate at similar rates, causing rapid (days-weeks) ‘resetting’ of the original isotopic abundances and trace element contents of the affected minerals. In copper sulfides, porosity-aided recrystallization occurs at lower temperatures (<300 °C) due to fast cation diffusion rates (log10D ≈ –13.6, 300 °C), but also takes place across other mineral systems where diffusion rates a

Near-infrared (NIR)-shielding glasses for energy-saving window applications were prepared by forming sodium tungsten bronze-like (Na5W14O44) functional units in the 29SiO2–43B2O3–28NaF glass matrix. The glasses were synthesized by a facile melt-quenching process where 4–8 mol.% H2WO4 was added as the W source. The optimal glass was produced using 6 mol.% H2WO4, which had a low NIR transmission of 15.4% and a high visible light transmission of 59.8%. The possible mechanism for the formation of Na5W14O44 in glasses were discussed based on XRD, Raman, XPS, XANES and EXAFS characterization of the glass samples, the glass samples after further crystallization, and the samples produced by staged heating of the starting materials. Crystalline or amorphous Na5W14O44 formed during heating partially due to the protection by molten B2O3. Subsequently, amorphous Na5W14O44 clusters are present in the glass acting as NIR-shielding functional units. This study sheds a light on further development of non-film-based and highly efficiency energy-saving windows.