Suppressing Zn pulverization with three-dimensional inert-cation diversion dam for long-life Zn metal batteries.

Tremendous attention has been paid to the water-associated side reactions and zinc (Zn) dendrite growth on the electrode-electrolyte interface. However, the Zn pulverization that can cause continuous depletion of active Zn metal and exacerbate hydrogen evolution is severely neglected. Here, we disclose that the excessive Zn feeding that causes incomplete crystallization is responsible for Zn pulverization formation through analyzing the thermodynamic and kinetics process of Zn deposition. On the basis, we introduce 1-ethyl-3-methylimidazolium cations (EMIm+) into the electrolyte to form a Galton-board-like three-dimensional inert-cation (3DIC) region. Modeling test shows that the 3DIC EMIm+ can induce the Zn2+ flux to follow in a Gauss distribution, thus acting as elastic sites to buffer the perpendicular diffusion of Zn2+ and direct the lateral diffusion, thus effectively avoiding the local Zn2+ accumulation and irreversible crystal formation. Consequently, anti-pulverized Zn metal deposition behavior is achieved with an average Coulombic efficiency of 99.6% at 5 mA cm-2 over 2,000 cycles and superb stability in symmetric cell over 1,200 h at -30 °C. Furthermore, the Zn||KVOH pouch cell can stably cycle over 1,200 cycles at 2 A g-1 and maintain a capacity of up to 12 mAh.

Suppressing metal corrosion through identification of optimal crystallographic plane for Zn batteries.

Direct use of metals as battery anodes could significantly boost the energy density, but suffers from limited cycling. To make the batteries more sustainable, one strategy is mitigating the propensity for metals to form random morphology during plating through orientation regulation, e.g., hexagonal Zn platelets locked horizontally by epitaxial electrodeposition or vertically aligned through Zn/electrolyte interface modulation. Current strategies center around obtaining (002) faceted deposition due to its minimum surface energy. Here, benefiting from the capability of preparing a library of faceted monocrystalline Zn anodes and controlling the orientation of Zn platelet deposits, we challenge this conventional belief. We show that while monocrystalline (002) faceted Zn electrode with horizontal epitaxy indeed promises the highest critical current density, the (100) faceted electrode with vertically aligned deposits is the most important one in suppressing Zn metal corrosion and promising the best reversibility. Such uniqueness results from the lowest electrochemical surface area of (100) faceted electrode, which intrinsically builds upon the surface atom diffusion barrier and the orientation of the pallets. These new findings based on monocrystalline anodes advance the fundamental understanding of electrodeposition process for sustainable metal batteries and provide a paradigm to explore the processing-structure-property relationships of metal electrodes.

Dual-axial engineering on atomically dispersed catalysts for ultrastable oxygen reduction in acidic and alkaline solutions.

Atomically dispersed catalysts are a promising alternative to platinum group metal catalysts for catalyzing the oxygen reduction reaction (ORR), while limited durability during the electrocatalytic process severely restricts their practical application. Here, we report an atomically dispersed Co-doped carbon-nitrogen bilayer catalyst with unique dual-axial Co-C bonds (denoted as Co/DACN) by a smart phenyl-carbon-induced strategy, realizing highly efficient electrocatalytic ORR in both alkaline and acidic media. The corresponding half-wave potential for ORR is up to 0.85 and 0.77 V (vs. reversible hydrogen electrode (RHE)) in 0.5 M H2SO4 and 0.1 M KOH, respectively, representing the best ORR activity among all non-noble metal catalysts reported to date. Impressively, the Zn-air battery (ZAB) equipped with Co/DACN cathode achieves outstanding durability after 1,688 h operation at 10 mA cm-2 with a high current density (154.2 mA cm-2) and a peak power density (210.1 mW cm-2). Density functional theory calculations reveal that the unique dual-axial cross-linking Co-C bonds of Co/DACN significantly enhance the stability during ORR and also facilitate the 4e- ORR pathway by forming a joint electron pool due to the improved interlayer electron mobility. We believe that axial engineering opens a broad avenue to develop high-performance heterogeneous electrocatalysts for advanced energy conversion and storage.

Structural insights into human zinc transporter ZnT1 mediated Zn2+ efflux.

Zinc transporter 1 (ZnT1), the principal carrier of cytosolic zinc to the extracellular milieu, is important for cellular zinc homeostasis and resistance to zinc toxicity. Despite recent advancements in the structural characterization of various zinc transporters, the mechanism by which ZnTs-mediated Zn2+ translocation is coupled with H+ or Ca2+ remains unclear. To visualize the transport dynamics, we determined the cryo-electron microscopy (cryo-EM) structures of human ZnT1 at different functional states. ZnT1 dimerizes via extensive interactions between the cytosolic (CTD), the transmembrane (TMD), and the unique cysteine-rich extracellular (ECD) domains. At pH 7.5, both protomers adopt an outward-facing (OF) conformation, with Zn2+ ions coordinated at the TMD binding site by distinct compositions. At pH 6.0, ZnT1 complexed with Zn2+ exhibits various conformations [OF/OF, OF/IF (inward-facing), and IF/IF]. These conformational snapshots, together with biochemical investigation and molecular dynamic simulations, shed light on the mechanism underlying the proton-dependence of ZnT1 transport.

Revealing the missing puzzle piece of concentration in regulating Zn electrodeposition.

Despite achievements in suppressing dendrites and regulating Zn crystal growth, secondary aqueous Zn batteries are still rare in the market. Existing strategies mainly focus on electrode modification and electrolyte optimization, while the essential role of ion concentration in liquid-to-solid electrodeposition is neglected for a long time. Herein, the mechanism of concentration regulation in Zn electrodeposition is investigated in depth by combining electrochemical tests, post hoc characterization, and multiscale simulations. First, initial Zn electrodeposition is thermodynamically controlled epitaxial growth, whereas with the rapid depletion of ions, the concentration overpotential transcends the thermodynamic influence to kinetic control. Then, the evolution of the morphology from 2D sheets to 1D whiskers due to the concentration change is insightfully revealed by the morphological characterization and phase-field modeling. Furthermore, the depth of discharge (DOD) results in large concentration differences at the electrode-electrolyte interface, with a mild concentration distribution at lower DOD generating (002) crystal plane 2D sheets and a heavily varied concentration distribution at higher DOD yielding arbitrarily oriented 3D blocks. As a proof of concept, relaxation is introduced into two systems to homogenize the concentration distribution, revalidating the essential role of concentration in regulating electrodeposition, and two vital factors affecting the relaxation time, i.e., current density and electrode distance, are deeply investigated, demonstrating that the relaxation time is positively related to both and is more sensitive to the electrode distance. This work contributes to reacquainting aqueous batteries undergoing phase transitions and reveals a missing piece of the puzzle in regulating Zn electrodeposition.

Zinc-Finger Protein ZFP488 Regulates the Timing of Oligodendrocyte Myelination and Remyelination.

Oligodendrocyte myelination and remyelination after injury are intricately regulated by various intrinsic and extrinsic factors, including transcriptional regulators. Among these, the zinc-finger protein ZFP488 is an oligodendrocyte-enriched transcriptional regulator that promotes oligodendrocyte differentiation in the developing neural tube and in oligodendroglial cell lines. However, the specific in vivo genetic requirements for ZFP488 during oligodendrocyte development and remyelination have not been defined. To address this gap, we generated a lineage-traceable ZFP488 knock-out mouse line, wherein an H2b-GFP reporter replaces the ZFP488-coding region. Using these mice of either sex, we examined the dynamics of ZFP488 expression from the endogenous promoter in the developing central nervous system (CNS). We observed a unique expression pattern in the oligodendrocyte lineage, with ZFP488 expression particularly enriched in differentiated oligodendrocytes. ZFP488 loss resulted in delayed myelination in the developing CNS and impaired remyelination after demyelinating injury in the brain. Integrated transcriptomic and genomic profiling further revealed that ZFP488 loss decreased the expression of myelination-associated genes but not oligodendrocyte progenitor-associated genes, suggesting that ZFP488 serves as a positive regulator of myelination by regulating maturation programs. Thus, our genetic loss-of-function study revealed that ZFP488 regulates a stage-dependent differentiation program that controls the timing of CNS myelination and remyelination.

ZNT5-6 and ZNT7 play an integral role in protein N-glycosylation by supplying Zn2+ to Golgi α-mannosidase II.

The stepwise addition of monosaccharides to N-glycans attached to client proteins to generate a repertoire of mature proteins involves a concerted action of many glycosidases and glycosyltransferases. Here, we report that Golgi α-mannosidase II (GMII), a pivotal enzyme catalyzing the first step in the conversion of hybrid- to complex-type N-glycans, is activated by Zn2+ supplied by the early secretory compartment-resident ZNT5-ZNT6 heterodimers (ZNT5-6) and ZNT7 homodimers (ZNT7). Loss of ZNT5-6 and ZNT7 function results in marked accumulation of hybrid-type and complex/hybrid glycans with concomitant reduction of complex- and high-mannose-type glycans. In cells lacking the ZNT5-6 and ZNT7 functions, the GMII activity is substantially decreased. In contrast, the activity of its homolog, lysosomal mannosidase (LAMAN), is not decreased. Moreover, we show that the growth of pancreatic cancer MIA PaCa-2 cells lacking ZNT5-6 and ZNT7 is significantly decreased in a nude mouse xenograft model. Our results indicate the integral roles of ZNT5-6 and ZNT7 in N-glycosylation and highlight their potential as novel target proteins for cancer therapy.

Natural antisense transcription of presenilin in sea urchin reveals a possible role for natural antisense transcription in the general control of gene expression during development

One presenilin gene (PSEN) is expressed in the sea urchin embryo, in the vegetal pole of the gastrula and then mainly in cilia cells located around the digestive system of the pluteus, as we recently have reported. PSEN expression must be accurately regulated for correct execution of these two steps of development. While investigating PSEN expression changes in embryos after expansion of endoderm with LiCl or of ectoderm with Zn2+ by whole-mount in situ hybridization (WISH) and quantitative PCR (qPCR), we detected natural antisense transcription of PSEN. We then found that Endo16 and Wnt5, markers of endo-mesoderm, and of Hnf6 and Gsc, markers of ectoderm, are also sense and antisense transcribed. We discuss that general gene expression could depend on both sense and antisense transcription. This mechanism, together with the PSEN gene, should be included in gene regulatory networks (GRNs) that theorize diverse processes in this species. We suggest that it would also be relevant to investigate natural antisense transcription of PSEN in the field of Alzheimer's disease (AD) where the role of human PSEN1 and PSEN2 is well known.

Loss of a single Zn finger, but not that of two Zn fingers, of GATA3 drives skin inflammation.

Transcription factor GATA3 is essential for the developmental processes of T cells. Recently, the silencer of a cytokine IFNγ gene was identified, the inhibitory activity of which requires GATA3. GATA3 has 2 Zn fingers and the commonly used GATA3 deficient mice lack both fingers (D2). We have established a mouse line that lacks only one Zn finger close to the C terminus (D1). The D1 mice line developed dermatitis, which was not observed in D2 mice. The expression of S100a8/S100a9 was elevated in D1 to a level higher than in D2, suggesting their roles in dermatitis development. CD8 T cells of both D1 and D2 lines expressed inhibitory receptors associated with the exhausted state. In the absence of MHC class II, the skin inflammation was exacerbated in both lines. The gene expression pattern of CD8 T cells became similar to that of effector T cells. Blocking Ab against LAG3 upregulated the expression of the effector molecules of T cells. These results suggest that the disfunction of GATA3 can lead to the spontaneous activation of CD8 T cells that causes skin inflammation, and that suppressive activity of MHC class II - LAG3 interaction ameliorates dermatitis development.

SENP1 mediates zinc-induced ZnT6 deSUMOylation at Lys-409 involved in the regulation of zinc metabolism in Golgi apparatus.

Zinc (Zn) transporters contribute to the maintenance of intracellular Zn homeostasis in vertebrate, whose activity and function are modulated by post-translational modification. However, the function of small ubiquitin-like modifier (SUMOylation) in Zn metabolism remains elusive. Here, compared with low Zn group, a high-Zn diet significantly increases hepatic Zn content and upregulates the expression of metal-response element-binding transcription factor-1 (MTF-1), Zn transporter 6 (ZnT6) and deSUMOylation enzymes (SENP1, SENP2, and SENP6), but inhibits the expression of SUMO proteins and the E1, E2, and E3 enzymes. Mechanistically, Zn triggers the activation of the MTF-1/SENP1 pathway, resulting in the reduction of ZnT6 SUMOylation at Lys 409 by small ubiquitin-like modifier 1 (SUMO1), and promoting the deSUMOylation process mediated by SENP1. SUMOylation modification of ZnT6 has no influence on its localization but reduces its protein stability. Importantly, deSUMOylation of ZnT6 is crucial for controlling Zn export from the cytosols into the Golgi apparatus. In conclusion, for the first time, we elucidate a novel mechanism by which SUMO1-catalyzed SUMOylation and SENP1-mediated deSUMOylation of ZnT6 orchestrate the regulation of Zn metabolism within the Golgi apparatus.

Real-space determination of the isolated magnetic skyrmion deformation under electric current flow.

The manipulation and control of electron spins, the fundamental building blocks of magnetic domains and spin textures, are at the core of spintronics. Of particular interest is the effect of the electric current on topological magnetic skyrmions, such as the current-induced deformation of isolated skyrmions. The deformation has consequences ranging from perturbed dynamics to modified packing configurations. In this study, we measured the current-driven real-space deformation of isolated, pinned skyrmions within Co10Zn10 at room temperature. We observed that the skyrmions are surprisingly soft, readily deforming during electric current application into an elliptical shape with a well-defined deformation axis (semimajor axis). We found that this axis rotates unidirectionally toward the current direction irrespective of electric current polarity and that the elliptical deformation reverses back upon current termination. We quantified the average distortion δ, which increased by ∼90% during the largest applied current density |j| = 8.46 ×109 A/m2 when compared with the skyrmion's intrinsic shape ([Formula: see text]). Additionally, we demonstrated an approximately 120% average skyrmion core size expansion during current application, highlighting the skyrmions' inherent topological protection. This evaluation of in situ electric current-induced skyrmion deformation paints a clearer picture of spin-polarized electron-skyrmion interactions and may prove essential in designing spintronic devices.

Highly reversible Zn metal anode enabled by sustainable hydroxyl chemistry.

Rechargeable Zn metal batteries (RZMBs) may provide a more sustainable and lower-cost alternative to established battery technologies in meeting energy storage applications of the future. However, the most promising electrolytes for RZMBs are generally aqueous and require high concentrations of salt(s) to bring efficiencies toward commercially viable levels and mitigate water-originated parasitic reactions including hydrogen evolution and corrosion. Electrolytes based on nonaqueous solvents are promising for avoiding these issues, but full cell performance demonstrations with solvents other than water have been very limited. To address these challenges, we investigated MeOH as an alternative electrolyte solvent. These MeOH-based electrolytes exhibited exceptional Zn reversibility over a wide temperature range, with a Coulombic efficiency > 99.5% at 50% Zn utilization without cell short-circuit behavior for > 1,800 h. More important, this remarkable performance translates well to Zn || metal-free organic cathode full cells, supporting < 6% capacity decay after > 800 cycles at -40 °C.

Chemically coupling SnO2 quantum dots and MXene for efficient CO2 electroreduction to formate and Zn-CO2 battery.

Electrochemical conversion of CO2 into formate is a promising strategy for mitigating the energy and environmental crisis, but simultaneously achieving high selectivity and activity of electrocatalysts remains challenging. Here, we report low-dimensional SnO2 quantum dots chemically coupled with ultrathin Ti3C2Tx MXene nanosheets (SnO2/MXene) that boost the CO2 conversion. The coupling structure is well visualized and verified by high-resolution electron tomography together with nanoscale scanning transmission X-ray microscopy and ptychography imaging. The catalyst achieves a large partial current density of -57.8 mA cm-2 and high Faradaic efficiency of 94% for formate formation. Additionally, the SnO2/MXene cathode shows excellent Zn-CO2 battery performance, with a maximum power density of 4.28 mW cm-2, an open-circuit voltage of 0.83 V, and superior rechargeability of 60 h. In situ X-ray absorption spectroscopy analysis and first-principles calculations reveal that this remarkable performance is attributed to the unique and stable structure of the SnO2/MXene, which can significantly reduce the reaction energy of CO2 hydrogenation to formate by increasing the surface coverage of adsorbed hydrogen.

Quantitative, in situ visualization of intracellular insulin vesicles in pancreatic beta cells.

Characterizing relationships between Zn2+, insulin, and insulin vesicles is of vital importance to the study of pancreatic beta cells. However, the precise content of Zn2+ and the specific location of insulin inside insulin vesicles are not clear, which hinders a thorough understanding of the insulin secretion process and diseases caused by blood sugar dysregulation. Here, we demonstrated the colocalization of Zn2+ and insulin in both single extracellular insulin vesicles and pancreatic beta cells by using an X-ray scanning coherent diffraction imaging (ptychography) technique. We also analyzed the elemental Zn2+ and Ca2+ contents of insulin vesicles using electron microscopy and energy dispersive spectroscopy (EDS) mapping. We found that the presence of Zn2+ is an important characteristic that can be used to distinguish insulin vesicles from other types of vesicles in pancreatic beta cells and that the content of Zn2+ is proportional to the size of insulin vesicles. By using dual-energy contrast X-ray microscopy and scanning transmission X-ray microscopy (STXM) image stacks, we observed that insulin accumulates in the off-center position of extracellular insulin vesicles. Furthermore, the spatial distribution of insulin vesicles and their colocalization with other organelles inside pancreatic beta cells were demonstrated using three-dimensional (3D) imaging by combining X-ray ptychography and an equally sloped tomography (EST) algorithm. This study describes a powerful method to univocally describe the location and quantitative analysis of intracellular insulin, which will be of great significance to the study of diabetes and other blood sugar diseases.

Mediating Zn Ions Migration Behavior via ß-Cyclodextrin Modified Carbon Nanotube Film for High-Performance Zn Anodes.

Metallic Zn is considered as a promising anode material because of its abundance, eco-friendliness, and high theoretical capacity. However, the uncontrolled dendrite growth and side reactions restrict its further practical application. Herein, we proposed a ß-cyclodextrin-modified multiwalled carbon nanotube (CD-MWCNT) layer for Zn metal anodes. The obtained CD-MWCNT layer with high affinity to Zn can significantly reduce the transfer barrier of Zn2+ at the electrode/electrolyte interface, facilitating the uniform deposition of Zn2+ and suppressing water-caused side reactions. Consequently, the Zn||Zn symmetric cell assembled with CD-MWCNT shows a significantly enhanced cycling durability, maintaining a cycling life exceeding 1000 h even under a high current density of 5 mA cm-2. Furthermore, the full battery equipped with a V2O5 cathode displays an unparalleled long life. This work unveils a promising avenue toward the achievement of high-performance Zn metal anodes.

Rationally Engineering a Quasi-Solid-State Flexible Self-Healing Secondary Battery Using Hydrogel-Based Water-in-Salt Electrolyte and Electrochemically Deposited Electrodes.

High safety and low cost are essential for energy-storage systems. Here, an aqueous zinc ion battery composed of a hydrogel-based water-in-salt electrolyte prepared by photoinitiated polymerization of acrylamide in ZnCl2 solution (named as PZC) and flexible electrodes is developed. The stable performance in Zn||Zn symmetric cells and high Coulombic efficiency of PZC in Zn||Cu asymmetric cells verify dendrite suppression. VO2 nanobelts coated with polyaniline (PANI) are grown on a carbon cloth (CC). The battery shows a capacity of 221.5 mAh g-1 after 200 cycles. The batteries present high recovery performance after bending/cutting. After bending of 60°, 90°, and 180°, capacities remain at 240.0, 205.4, and 175.2 mAh g-1, respectively; while the battery healed from 1, 2, 3, and 4 times of cutting shows 197.5, 174.3, 124.7, and 101.2 mAh g-1, respectively. Our findings enable the engineering of a quasi-solid-state battery to have good capability for flexible and portable electronics.

Trade-Off between Rough and Smooth Electrode Surfaces toward Stable Zn Stripping/Plating in Aqueous Electrolytes.

The effects of surface roughness on the performance of the Zn metal anode in aqueous electrolytes are investigated by experiments and computational simulations. Smooth surfaces can homogenize the nucleation and growth of Zn, which helps to form a flat Zn anode under high current density. In spite of these advantages, the whole surface of the smooth electrode serves as the reactive contact area for parasitic reactions, generating severe hydrogen evolution, corrosion, and byproduct formation, which seriously hinder the long-term cycle stability of the Zn anode. To trade off this double-sided effect, we identify a medium degree of surface roughness that could stabilize the Zn anode for 1000 h cycling at 1.0 mAh cm-2. The electrode also enabled stable cycling for 800 h at a high current density of 5.0 mAh cm-2. This naked Zn metal anode with optimized surface roughness holds great promise for direct use in aqueous zinc ion batteries.

Active Dendrite Suppression by Ferroelectric Membrane Separators in Rechargeable Batteries.

Anodic dendrite formation is a critical issue in rechargeable batteries and often leads to poor cycling stability and quick capacity loss. Prevailing strategies for dendrite suppression aim at slowing down the growth rate kinetically but still leaving possibilities for dendrite evolution over time. Herein, we report a complete dendrite elimination strategy using a mesoporous ferroelectric polymer membrane as the battery separator. The dendrite suppression is realized by spontaneously reversing the surface energetics for metal ion reduction at the protrusion front, where a positive piezoelectric polarization is generated and superimposed as the protrusion compresses the separator. This effect is demonstrated first in a Zn electroplating process, and further in Zn-Zn symmetric cells and Zn-NaV3O8·1.5H2O full cells, where the dendritic Zn anode surfaces are completely turned into featureless flat surfaces. Consequently, a substantially longer charging/discharging cycle is achieved. This study provides a promising pathway toward high-performance dendrite-free rechargeable batteries.

High-Performance Aqueous Calcium Ion Batteries Enabled by Zn Metal Anodes with Stable Ion-Conducting Interphases.

Aqueous calcium ion batteries, promising for energy storage, are still challenged by very limited anode choices. Although a Zn metal anode is popular in aqueous batteries, interface instability due to incessant corrosion and severe Zn dendrites hinders its development. Here, an interphase layer with densely packed nanocrystals of Ca3(CO3)2(OH)2·1.5H2O and ZnF2, and amorphous organic species, is demonstrated for a Zn metal anode with 1 M calcium trifluoromethyl sulfonate aqueous electrolyte. The hybrid interface fully avoids direct Zn-H2O contact, maintains fast ion conductivity, and effectively prevents corrosion and dendrite growth. Therefore, the symmetric cell stably lasts for 1600 h at 0.5 mA cm-2 and 2.5 mAh cm-2, far superior to 150 h for the control cell. Furthermore, the device maintains 80% capacity retention after 700 cycles at 1 A g-1, outperforming 13% retention after 200 cycles for the control device. This work indicates that interface and interphase engineering is also crucial for aqueous batteries.

Pumping Electrons from Oxygen-Bridged Cobalt for Low-Charging-Voltage Zn-Air Batteries.

Reducing the charging voltage is a prerequisite for improving the chargeability and energy efficiency of Zn-air batteries (ZABs). Herein, Fe3+ pumps electrons from oxygen-bridged cobalt (Fe-O-Co) and induces the accelerated charging kinetics. For the liquid ZABs, a charging voltage of around 1.94 V at 10 mA cm-2 was displayed, which slightly increased 2% after continuous cycles for 180 h. A steady charging voltage of around 1.87 V at 10 mA cm-2 was also exhibited for quasi-solid-state ZABs. Control experiments and characterization show that the interactions between the O2- and Fe3+ sites are relatively weaker than those between the O2- and Co3+ sites. Compared with Mn3+, Zn2+, and Cu2+, Fe3+ effectively pumps electrons from Co sites to generate the active species for the oxygen evolution reaction. Thus, the deprotonation behavior and *OH conversion were improved. This work demonstrates the oxygen electron bridge modulated electron transfer between dual metal sites, contributing to the improvement of low-charging-voltage ZABs.