Showing papers on "Nucleation published in 2023"

Reversible Zn metal anodes enabled by trace amounts of underpotential deposition initiators.

Abstract: Routine electrolyte additives are not effective enough for uniform zinc (Zn) deposition, because they are hard to proactively guide atomic-level Zn deposition. Here, based on underpotential deposition (UPD), we propose an "escort effect" of electrolyte additives for uniform Zn deposition at the atomic level. With nickel ion (Ni2+) additives, we found that metallic Ni deposits preferentially and triggers the UPD of Zn on Ni. This facilitates firm nucleation and uniform growth of Zn while suppressing side reactions. Besides, Ni dissolves back into the electrolyte after Zn stripping with no influence on interfacial charge transfer resistance. Consequently, the optimized cell operates for over 900 h at 1 mA cm-2 (more than 4 times longer than the blank one). Moreover, the universality of "escort effect" is identified by using Cr3+ and Co2+ additives. This work would inspire a wide range of atomic-level principles by controlling interfacial electrochemistry for various metal batteries.

Modulation of Nucleation and Crystallization in PbI2 Films Promoting Preferential Perovskite Orientation Growth for Efficient Solar Cells

Abstract: Formamidinium (FA)-rich lead iodide perovskite solar cells (PSCs) are gaining popularity because of their excellent photovoltaic performance. Nevertheless, the FA-rich perovskites processed by a two-step sequential deposition method usually possess...

Spontaneous nucleation and fast aggregate-dependent proliferation of α-synuclein aggregates within liquid condensates at neutral pH

Abstract: Significance It has been recently shown that the speed of the conversion of α-synuclein from its native state into amyloid fibrils can be greatly enhanced by the formation of an intermediate dense liquid state formed through phase separation. The corresponding mechanism, however, remains to be fully characterized. In this work, we use a combination of fluorescence microscopy, microfluidics, and chemical kinetics to determine the microscopic rate constants for the primary nucleation and aggregate-dependent proliferation at neutral pH of α-synuclein fibrils. The approach that we report facilitates the study of the aggregation process of α-synuclein under physiological conditions and of its relationship with Parkinson’s disease and related synucleinopathies.

Realizing Textured Zinc Metal Anodes through Regulating Electrodeposition Current for Aqueous Zinc Batteries.

Abstract: Crystallography modulation of zinc (Zn) metal anode is promising to promote Zn reversibility in aqueous electrolytes, but efficiently constructing Zn with specific crystallographic texture remains challenging. Herein, we report a current-controlled electrodeposition strategy to texture the Zn electrodeposits in conventional aqueous electrolytes. Using the electrolytic cell with low-cost Zn(CH3COO)2 electrolyte and Cu substrate as a model system, the texture of as-deposited Zn gradually transforms from (101) to (002) crystal plane as increasing the current density from 20 to 80 mA cm-2. Moreover, the high current accelerates the Zn nucleation rate with abundant nuclei, enabling uniform deposition. The (002) texture permits stronger resistance to dendrite growth and interfacial side reactions than the (101) texture. The resultant (002)-textured Zn electrode achieves deep cycling stability and supports the stable operation of full batteries with conventional V/Mn-based oxide cathodes.

Low-Temperature Potassium Batteries Enabled by electric and Thermal Field Regulation.

Abstract: Recharging batteries operate at sub-zero temperature is usually limited by the slow ion diffusion and uneven charge distribution at low temperature. Here, we report a strategy to regulate electric field and thermal field simultaneously, creating a fast and uniform deposition surroundings for potassium ion in potassium metal batteries (PMBs). This regulation is achieved by using a highly ordered 1D nanoarray electrode which provides a dense and flat surface for uniforming the electric field and high thermal conductivity for reducing the temperature fluctuation. Consequently, this electrode could achieve high-areal capacity of 10 mAh cm-2. Besides, the dependence of potassium nucleation on temperature is unveiled. Furthermore, a full-cell could steady operate with over 80% of its room-temperature capacity at -20°C. Those respectable performances demonstrate that this strategy is valid, potentially providing guidelines for the rational design of advanced electrodes toward PMBs.

A different attempt to analysis friction stir spot welding of AA5083-copper alloys

Abstract: A study has been made on the possibility of friction stir spot welding (FSSW) of the aluminium to copper sheet with SiC nanoparticles. Modified microstructures with different morphologies and properties were observed in the joint interface. It has been shown that the reinforcing particles cause an increasing role in the developed mechanical properties of joint samples such as strength and hardness due to the more particle-stimulated nucleation of recrystallisation (PSN), Zener pinning effect, and larger tension for the movement of dislocations. The experimental measurements indicated that AlCu and Al2Cu were the main intermetallic compounds formed in the interfacial region. It was concluded from fracture surfaces that ductile fracture is the primary fracture mode during the FSSW with SiC reinforcing particles.

Recent Advances in C-S-H Nucleation Seeding for Improving Cement Performances

Abstract: Reducing cement CO2 footprint is a societal need. This is being achieved mainly by replacing an increasing amount of Portland clinker by supplementary cementitious materials. However, this comes at a price: lower mechanical strengths at early ages due to slow pozzolanic reaction(s). This is being addressed by using accelerator admixtures. In this context, calcium silicate hydrate nucleation seeding seems to have a promising future, as it can accelerate cement and pozzolanic reactions at early ages, optimising their microstructures, without compromising late strength and durability performances. In fact, these features could even be improved. Moreover, other uses are low temperature concreting, precasting, shotconcrete, etc. Here, we focus on reviewing recent reports on calcium silicate hydrate seeding using commercially available admixtures. Current knowledge on the consequences of nucleation seeding on hydration reactions and on early and late mechanical strengths is discussed. It is noted that other features, in addition to the classic alite hydration acceleration, are covered here including the enhanced ettringite precipitation and the very efficient porosity refinement, which take place in the seeded binders. Finally, because the seeded binders seem to be denser, durability properties could also be enhanced although this remains to be properly established.

2D Mesoporous Zincophilic Sieve for High-Rate Sulfur-Based Aqueous Zinc Batteries.

Abstract: Sulfur-based aqueous zinc batteries (SZBs) attract increasing interest due to their integrated high capacity, competitive energy density, and low cost. However, the hardly reported anodic polarization seriously deteriorates the lifespan and energy density of SZBs at a high current density. Here, we develop an integrated acid-assisted confined self-assembly method (ACSA) to elaborate a two-dimensional (2D) mesoporous zincophilic sieve (2DZS) as the kinetic interface. The as-prepared 2DZS interface presents a unique 2D nanosheet morphology with abundant zincophilic sites, hydrophobic properties, and small-sized mesopores. Therefore, the 2DZS interface plays a bifunctional role in reducing the nucleation and plateau overpotential: (a) accelerating the Zn2+ diffusion kinetics through the opened zincophilic channels and (b) inhibiting the kinetic competition of hydrogen evolution and dendrite growth via the significant solvation-sheath sieving effect. Therefore, the anodic polarization is reduced to 48 mV at 20 mA cm-2, and the full-battery polarization is reduced to 42% of an unmodified SZB. As a result, an ultrahigh energy density of 866 Wh kgsulfur-1 at 1 A g-1 and a long lifespan of 10,000 cycles at a high rate of 8 A g-1 are achieved.

Metallic Zinc Anode Working at 50 and 50 mAh cm−2 with High Depth of Discharge via Electrical Double Layer Reconstruction

Abstract: Achieving high‐rate and high‐areal‐capacity Zn anode with high depth of discharge (DOD) offers a bright future for large‐scale aqueous batteries. However, Zn deposition suffers from severe dendrite growth and side reactions, which compromises achievable lifetime. Herein, an electrical double layer (EDL) reconstruction strategy is proposed by employing acetone as electrolyte additive to fully address these issues. Experimental and theoretical simulation results reveal that the adsorption priority of acetone to water on Zn creates a water‐poor inner Helmholtz layer. Meanwhile, the intense hydrogen bonding effect between acetone and water confines the activity of free water and weakens the Zn2+ solvation in the outer Helmholtz layer and diffusion layer. Such ion/molecule rearrangement in EDL suppresses hydrogen evolution, facilitates the desolvation process, and promotes the Zn2+ diffusion kinetics, which guides homogeneous Zn nucleation and uniform growth, even in extreme situations. At both ultrahigh current density of 50 mA cm−2 and areal capacity of 50 mAh cm−2, the addition of 20 v/v% acetone in 2 m ZnSO4 extends the lifespan of Zn//Zn symmetric cells from 12 to 800 h, with a high DOD of 73.5%. The effectiveness of this strategy is further demonstrated in the Zn‐MnO2 full batteries at wide temperature range from −30 to 40 °C.

The effect of heat treatment on the room and high temperature mechanical properties of AlSi10Mg alloy fabricated by selective laser melting

Abstract: The present work demonstrates a novel interpretation of the effect of well-known heat treatments of solutionizing (ST) and solutionizing plus aging (T6) along with a newly-developed direct aging (DA), on the microstructural evolution and corresponding deformation behavior of selectively laser-melted AlSi10Mg alloy. To this end, different heat treatments were employed to not only modify the microstructure but also adjust the defect structure. Furthermore, the monotonically deformed microstructures and the corresponding fractured surface at temperatures of 25 and 200 °C was studied to address the effect of post-processes on the damage mechanism. Surprisingly, it has been understood that the flow responses of the treated microstructures haven't improved as much as it was expected. That is attributed to the deteriorating effect of dissolving the cellular structure along with its considerable impact on trapped gas defect. Furthermore, the melt pool boundaries (MPB) found to be prone to crack nucleation and growth owing to the high connectivity of Si-network and strain localization in heat-treated specimens as well as in As-built ones. Small precipitates from the inner part of the melt pool were likely to agglomerate in the heat-affected zone (HAZ) under the Ostwald ripening mechanism where these primary coarse Si precipitates had existed.

Tetraspanin 4 stabilizes membrane swellings and facilitates their maturation into migrasomes

Abstract: Abstract Migrasomes are newly discovered cell organelles forming by local swelling of retraction fibers. The migrasome formation critically depends on tetraspanin proteins present in the retraction fiber membranes and is modulated by the membrane tension and bending rigidity. It remained unknown how and in which time sequence these factors are involved in migrasome nucleation, growth, and stabilization, and what are the possible intermediate stages of migrasome biogenesis. Here using live cell imaging and a biomimetic system for migrasomes and retraction fibers, we reveal that migrasome formation is a two-stage process. At the first stage, which in biomimetic system is mediated by membrane tension, local swellings largely devoid of tetraspanin 4 form on the retraction fibers. At the second stage, tetraspanin 4 molecules migrate toward and onto these swellings, which grow up to several microns in size and transform into migrasomes. This tetraspanin 4 recruitment to the swellings is essential for migrasome growth and stabilization. Based on these findings we propose that the major role of tetraspanin proteins is in stabilizing the migrasome structure, while the migrasome nucleation and initial growth stages can be driven by membrane mechanical stresses.

Achieving Stable Zinc Metal Anode Via Polyaniline Interface Regulation of Zn Ion Flux and Desolvation

Abstract: Aqueous zinc-ion batteries feature high safety, low cost, and relatively high energy density; however, their cycle life is hindered by severe Zn dendrite formation and water-induced parasitic reactions. Herein, a porous polyaniline (PANI) interfacial layer is developed on the surface of Zn metal anode to regulate the transport and deposition of Zn2+, achieving an ultra-stable and highly reversible Zn anode. Specifically, the abundant polar groups (NH and N) in PANI have a strong attraction to H2O, which can trap and immobilize H2O molecules around Zn2+. Moreover, the protective layer regulates ion flux and deposition behavior of Zn2+ through the ion confinement effect. Consequently, the [email protected] anode exhibits improved reversible plating/stripping behavior with a low nucleation overpotential (37.9 mV) at 2.0 mA cm-2 compared to that of bare Zn anode. The MnO2//[email protected] cell demonstrates a high capacity retention of 94.3% after 1000 cycles at 1.0 A g−1. This study lays the foundation for accessible interface engineering and in-depth mechanistic analysis of Zn anode.