An autotransferable alloy overlayer toward stable sodium metal anodes.

Sodium (Na) metal anodes receive significant attention due to their high theoretical specific energy and cost-effectiveness. However, the high reactivity of Na foil anodes and the irregular surfaces have posed challenges to the operability and reliability of Na metals in battery applications. In the absence of inert environmental protection conditions, constructing a uniform, dense, and sodiophilic Na metal anode surface is crucial for homogenizing Na deposition, but remains less-explored. Herein, we fabricated a Tin (Sn) nanoparticle-assembled film conforming to separator pores, which provided ample space for accommodating volumetric expansion during the Na alloying process. Subsequently, a seamless Na-Sn alloy overlayer was formed and transferred onto the Na foil during Na plating through a separator-assisted technique, thereby overcoming conventional operational limitations of metallic Na. As compared to traditional volumetrically expanded cracked ones, the present autotransferable, highly sodiophilic, ion-conductive, and seamless Na-Sn alloy overlayer serves as uniform nucleation sites, thereby reducing nucleation and diffusion barriers and facilitating the compact deposition of metallic Na. Consequently, the autotransferable alloy layer enables a high average Coulombic efficiency of 99.9 % at 3.0 mA cm-2 and 3.0 mAh cm-2 in the half cells as well as minimal polarization overpotentials in symmetric cells, both during prolonged cycling 1200 h. Furthermore, the assembled Na||Sn-1.0h-PP||Na3V2(PO4)3@C@CNTs full cell delivers high capacity retention of 97.5 % after 200 cycles at a high cathodic mass loading.

ApoE4 exacerbates the senescence of hippocampal neurons and spatial cognitive impairment by downregulating acetyl-CoA level.

Although aging and apolipoprotein E (APOE) ε4 allele have been documented as two major risk factors for late-onset Alzheimer's disease (LOAD), their interaction and potential underlying mechanisms remain unelucidated. Using humanized ApoE4- and ApoE3- target replacement mice, we found the accumulation of senescent neurons and the activation of mTOR and endosome-lysosome-autophagy (ELA) system in the hippocampus of aged ApoE4 mice. Further analyses revealed that ApoE4 aggravated the profile change of hippocampal transcription and metabolism in an age-dependent manner, accompanying with an disruption of metabolism, which is presented with the downregulating activity of citrate synthase, the level of ATP and, most importantly, the level of acetyl coenzyme A (Ac-CoA); GTA supplement, an Ac-CoA substrate, reversed the senescent characteristics, decreased the activation of mTOR and ELA system, and enhanced the synaptic structure and increasing level of pre-/post-synaptic plasticity-related protein, leading to cognitive improvement in aged ApoE4 mice. These data suggest that ApoE4 exacerbates neuronal senescence due to a deficiency of acetyl-CoA, which can be ameliorated by GTA supplement. The findings provide novel insights into the potential therapeutic value of GTA supplement for the cognitive improvement in aged APOE4 carriers.

ACSS2-dependent histone acetylation improves cognition in mouse model of Alzheimer's disease.

BACKGROUND: Nuclear acetyl-CoA pools govern histone acetylation that controls synaptic plasticity and contributes to cognitive deterioration in patients with Alzheimer's disease (AD). Nuclear acetyl-CoA pools are generated partially from local acetate that is metabolized by acetyl-CoA synthetase 2 (ACSS2). However, the underlying mechanism of histone acetylation dysregulation in AD remains poorly understood. METHODS: We detected ACSS2 expression and histone acetylation levels in the brains of AD patients and 5 × FAD mice. When we altered ACSS2 expression by injecting adeno-associated virus into the dorsal hippocampus of 5 × FAD mice and replenished ACSS2 substrate (acetate), we observed changes in cognitive function by Morris water maze. We next performed RNA-seq, ChIP-qPCR, and electrophysiology to study molecular mechanism underlying ACSS2-mediated spatial learning and memory in 5 × FAD mice. RESULTS: We reported that ACSS2 expression and histone acetylation (H3K9, H4K12) were reduced in the hippocampus and prefrontal cortex of 5 × FAD mice. Reduced ACSS2 levels were also observed in the temporal cortex of AD patients. 5 × FAD mice exhibited a low enrichment of acetylated histones on the promoters of NMDARs and AMPARs, together with impaired basal and activity-dependent synaptic plasticity, all of which were rescued by ACSS2 upregulation. Moreover, acetate replenishment enhanced ac-H3K9 and ac-H4K12 in 5 × FAD mice, leading to an increase of NMDARs and AMPARs and a restoration of synaptic plasticity and cognitive function in an ACSS2-dependent manner. CONCLUSION: ACSS2 is a key molecular switch of cognitive impairment and that targeting ACSS2 or acetate administration may serve as a novel therapeutic strategy for the treatment of intermediate or advanced AD. Nuclear acetyl-CoA pools are generated partly from local acetate that is metabolized by acetyl-CoA synthetase 2 (ACSS2). Model depicts that ACSS2 expression is downregulated in the brains of 5×FAD model mice and AD patients. Of note, ACSS2 downregulation mediates a reduction in ionotropic glutamate receptor expression through histone acetylation, which exacerbates synaptic plasticity impairment in AD. These deficits can be rescued by ACSS2 upregulation or acetate supplementation (GTA, an FDA-approved food additive), which may serve as a promising therapeutic strategy for AD treatment.

Semicrystalline IrOx with Abundant Boundaries for Overall Water Splitting.

Inorganic compounds with different crystalline and amorphous states may show distinct properties in catalytic applications. In this work, we control the crystallization level by fine thermal treatment and synthesize a semicrystalline IrOx material with the formation of abundant boundaries. Theoretical calculation reveals that the interfacial iridium with a high degree of unsaturation is highly active for the hydrogen evolution reaction compared to individual counterparts based on the optimal binding energy with hydrogen (H*). At the heat treatment temperature of 500 °C, the obtained IrOx-500 catalyst has dramatically promoted hydrogen evolution kinetics, endowing the iridium catalyst with a bifunctional activity for acidic overall water splitting with a total voltage of only 1.554 V at a current density of 10 mA cm-2. In light of the remarkable boundary-enhanced catalysis effects, the semicrystalline material should be further developed for other applications.

Combating Li metal deposits in all-solid-state battery via the piezoelectric and ferroelectric effects.

All-solid-state Li-metal batteries (ASSLBs) are highly desirable, due to their inherent safety and high energy density; however, the irregular and uncontrolled growth of Li filaments is detrimental to interfacial stability and safety. Herein, we report on the incorporation of piezo-/ferroelectric BaTiO3 (BTO) nanofibers into solid electrolytes and determination of electric-field distribution due to BTO inclusion that effectively regulates the nucleation and growth of Li dendrites. Theoretical simulations predict that the piezoelectric effect of BTO embedded in solid electrolyte reduces the driving force of dendrite growth at high curvatures, while its ferroelectricity reduces the overpotential, which helps to regularize Li deposition and Li+ flux. Polarization reversal of soft solid electrolytes was identified, confirming a regular deposition and morphology alteration of Li. As expected, the ASSLBs operating with LiFePO4/Li and poly(ethylene oxide) (PEO)/garnet solid electrolyte containing 10% BTO additive showed a steady and long cycle life with a reversible capacity of 103.2 mAh g-1 over 500 cycles at 1 C. Furthermore, the comparable cyclability and flexibility of the scalable pouch cells prepared and the successful validation in the sulfide electrolytes, demonstrating its universal and promising application for the integration of Li metal anodes in solid-state batteries.

Strategies for Electrochemically Sustainable H2 Production in Acid.

Acidified water electrolysis with fast kinetics is widely regarded as a promising option for producing H2 . The main challenge of this technique is the difficulty in realizing sustainable H2 production (SHP) because of the poor stability of most electrode catalysts, especially on the anode side, under strongly acidic and highly polarized electrochemical environments, which leads to surface corrosion and performance degradation. Research efforts focused on tuning the atomic/nano structures of catalysts have been made to address this stability issue, with only limited effectiveness because of inevitable catalyst degradation. A systems approach considering reaction types and system configurations/operations may provide innovative viewpoints and strategies for SHP, although these aspects have been overlooked thus far. This review provides an overview of acidified water electrolysis for systematic investigations of these aspects to achieve SHP. First, the fundamental principles of SHP are discussed. Then, recent advances on design of stable electrode materials are examined, and several new strategies for SHP are proposed, including fabrication of symmetrical heterogeneous electrolysis system and fluid homogeneous electrolysis system, as well as decoupling/hybrid-governed sustainability. Finally, remaining challenges and corresponding opportunities are outlined to stimulate endeavors toward the development of advanced acidified water electrolysis techniques for SHP.

Metformin alleviates the depression-like behaviors of elderly apoE4 mice via improving glucose metabolism and mitochondrial biogenesis.

Apolipoprotein E4 (apoE4) is closely related to late-onset depression (LOD). In addition, the benefits of metformin treatment of depression have been documented in a range of rodent studies and human trials, but few studies have probed into the effect of metformin on and the related mechanism in depressed elderly mice, especially in those APOE4 carriers. Here, we treated 13-month-old apoE3-targeted replacement (TR) and apoE4-TR mice with an intragastric administration of metformin (300 mg/kg/d) or normal saline for 5 months. We found that metformin exerted antidepressant effects on apoE4 mice, including reduced immobility time in TST and FST, and increased ratios of time and distance in the central area of OFT. Importantly, compared with apoE3 mice, apoE4 mice showed a higher expression of lactate dehydrogenase (LDH) and pyruvate dehydrogenase kinase (PDK1 and PDK4) in the hippocampus. The increased LDH level was rescued by metformin treatment. Moreover, the metformin administration increased the levels of transcriptional factor NRF-1 and TFAM, mtDNA, and most mitochondrial complex subunits in apoE-TR mice. Furthermore, it upregulated the expressions of antioxidant enzymes, such as MnSOD, GPX1, and GSR1/2. Interestingly, apoE4 blunted the hypoglycemic effect of metformin in aged mice. These data suggest that metformin ameliorates the depression-like behaviors probably by improving glucose metabolism and mitochondria biogenesis in the hippocampus of aged apoE4 mice. These findings imply that chronic metformin treatment can improve apoE4-mediated LOD, providing mechanistic insights for apoE4- and age-based depression prevention and therapy.

Swallowing Lithium Dendrites in All-Solid-State Battery by Lithiation with Silicon Nanoparticles.

Eliminating the uncontrolled growth of Li dendrite inside solid electrolytes is a critical tactic for the performance improvement of all-solid-state Li batteries (ASSLBs). Herein, a strategy to swallow and anchor Li dendrites by filling Si nanoparticles into the solid electrolytes by the lithiation effect with Li dendrites is proposed. It is found that Si nanoparticles can lithiate with the adjacent Li dendrites which have a strong electron transport ability. Such effect can inhibit the formation of Li dendrites at the interface of Li anode, and also swallow the tip Li inside the solid electrolytes, and thus inhibiting its longitudinal growth and avoiding the solid electrolyte puncturing. As a proof of concept, a novel sandwich-structure solid electrolyte of Li6.7 La3 Zr2 Al0.1 O12 (LLZA)-PEO/Si-PEO electrolyte/ (LLZA)-PEO with asymmetrical structure is first constructed and demonstrated stable Li plating/stripping over 1800 h and remarkably improved cycling stability in Li/LiFePO4 cells with a reversible capacity of 111.9 mAh g-1 at 1 C after 150 cycles. The proof of lithiation of Si-PEO electrolyte in the interlayer is also verified. Furthermore, the pouch cell thus prepared exhibits comparable cyclic stability and is allowable for folding and cutting, suggesting its promising application in ASSLBs by this simple and efficient strategy.

In situ surface reduction for accessing atomically dispersed platinum on carbon sheets for acidic hydrogen evolution.

Exploring the simple yet well-controlled synthesis of atomically dispersed Pt catalysts is a crucial endeavour for harvesting clean hydrogen via the kinetics-favoured acidic electrochemical water splitting technique. Here we employed the use of defective carbon sheets by KOH etching as a substrate for the in situ surface reduction of Pt(IV) ions to prepare atomically dispersed Pt. Physical and electrochemical characterizations reveal a strong interaction between the carbon substrate and Pt species, providing the basis for the in situ surface reduction. The atomically dispersed Pt electrocatalyst exhibited high HER performance in a sulfuric acid electrolyte, with an overpotential as low as 55 mV at a current density of 100 mA cm-a, and better catalytic durability compared to the commercial Pt/C. The mechanism study revealed that the full utilization of atomically dispersed Pt and the optimized catalyst surface may enhance the recombination of adsorbed *H via the Volmer-Tafel mechanism to produce H2 at a high efficiency. In the light of high activity, durability, and low cost, the atomically dispersed Pt material is promising for acidic HER application.

Electrochemical CO2 Reduction on Cu: Synthesis-Controlled Structure Preference and Selectivity.

The electrochemical CO2 reduction reaction (ECO2 RR) on Cu catalysts affords high-value-added products and is therefore of great practical significance. The outcome and kinetics of ECO2 RR remain insufficient, requiring essentially the optimized structure design for the employed Cu catalyst, and also the fine synthesis controls. Herein, synthesis-controlled structure preferences and the modulation of intermediate's interactions are considered to provide synthesis-related insights on the design of Cu catalysts for selective ECO2 RR. First, the origin of ECO2 RR intermediate-dominated selectivity is described. Advanced structural engineering approaches, involving alloy/compound formation, doping/defect introduction, and the use of specific crystal facets/amorphization, heterostructures, single-atom catalysts, surface modification, and nano-/microstructures, are then reviewed. In particular, these structural engineering approaches are discussed in association with diversified synthesis controls, and the modulation of intermediate generation, adsorption, reaction, and additional effects. The results pertaining to synthetic methodology-controlled structural preferences and the correspondingly motivated selectivity are further summarized. Finally, the current opportunities and challenges of Cu catalyst fabrication for highly selective ECO2 RR are discussed.

Complementary sample preparation strategies (PVD/BEXP) combining with multifunctional SPM for the characterizations of battery interfacial properties.

The cathode/anode-electrolyte interfaces in lithium/sodium ion batteries act as the "gate" for the ion exchange between the solid electrode and liquid electrolyte. Understanding the interfacial properties of these solid-liquid interfaces is essential for better design high-performance lithium/sodium ion batteries. Here, we provide a novel method for studying solid-liquid interfacial properties of battery materials through combining physical vapor deposition (PVD) and beam-exit cross-sectional polishing (BEXP) followed by controlled environment multifunctional Scanning Probe Microscope (SPM). In this method, commercial battery materials can be either directly grown on the current collector substrates, or polished by obliqued Ar-ion beams to get a nanoscale flat surface which allows the multifunctional SPM to study sample directly in the liquid electrolyte or in protective oxygen/H2O free environment. This approach allows to investigate wide range of interfacial properties, including surface morphology, internal cracks, mechanical properties, electronic/ionic conductivity and surface potential, with nanoscale resolution in-operando during the battery cycles as well as post-mortem.•PVD and novel BEXP methods were introduced to prepare battery powder materials as perfect specimens for nanoscale SPM characterization.•Various physical/chemical properties of battery materials can be probed on the as-prepared specimens under liquid electrolyte using in situ/operando SPM techniques.•Ex situ/post-mortem analyses based on the controlled environment multifunction SPM characterizations can be achieved in the BEXP polished degradation battery electrodes.

Simple Designed Micro-Nano Si-Graphite Hybrids for Lithium Storage.

Up to now, the silicon-graphite anode materials with commercial prospect for lithium batteries (LIBs) still face three dilemmas of the huge volume effect, the poor interface compatibility, and the high resistance. To address the above challenges, micro-nano structured composites of graphite coating by ZnO-incorporated and carbon-coated silicon (marked as Gr@ZnO-Si-C) are reasonably synthesized via an efficient and convenient method of liquid phase self-assembly synthesis combined with annealing treatment. The designed composites of Gr@ZnO-Si-C deliver excellent lithium battery performance with good rate performance and stable long-cycling life of 1000 cycles with reversible capacities of 1150 and 780 mAh g-1 tested at 600 and 1200 mA g-1 , respectively. The obtained results reveal that the incorporated ZnO effectively improve the interface compatibility between electrolyte and active materials, and boost the formation of compact and stable surface solid electrolyte interphase layer for electrodes. Furthermore, the pyrolytic carbon layer formed from polyacrylamide can directly improve electrical conductivity, decrease polarization, and thus promote their electrochemical performance. Finally, based on the scalable preparation of Gr@ZnO-Si-C composites, the pouch full cells of Gr@ZnO-Si-C||NCM523 are assembled and used to evaluate the commercial prospects of Si-graphite composites, offering highly useful information for researchers working in the battery industry.

In Situ Observation of the Insulator-To-Metal Transition and Nonequilibrium Phase Transition for Li1-xCoO2 Films with Preferred (003) Orientation Nanorods.

It is notoriously difficult to distinguish the stoichiometric LiCoO2 (LCO) with a O3-I structure from its lithium defective O3-II phase because of their similar crystal symmetry. Interestingly, moreover, the O3-II phase shows metallic conductivity, whereas the O3-I phase is an electronic insulator. How to effectively reveal the intrinsic mechanism of the conductivity difference and nonequilibrium phase transition induced by the lithium deintercalation is of vital importance for its practical application and development. Based on the developed technology of in situ peak force tunneling atomic force microscopy (PF-TUNA) in liquids, the phase transition from O3-I to O3-II and consequent insulator-to-metal transition of LCO thin-film electrodes with preferred (003) orientation nanorods designed and prepared via magnetron sputtering were observed under an organic electrolyte for the first time in this work. Then, studying the post-mortem LCO thin-film electrode by using ex situ time-dependent XRD and conductive atomic force microscopy, we find the phase relaxation of LCO electrodes after the nonequilibrium deintercalation, further proving the differences of the electronic conductivity and work function between the O3-I and O3-II phases. Moreover, X-ray absorption spectroscopy results indicate that the oxidation of Co ions and the increasing of O 2p-Co 3d hybridization in the O3-II phase lead to electrical conductivity improvement in Li1-xCoO2. Simultaneously, it is found that the nonequilibrium deintercalation at a high charging rate can result in phase-transition hysteresis and the O3-I/O3-II coexistence at the charging end, which is explained well by an ionic blockade model with an antiphase boundary. At last, this work strongly suggests that PF-TUNA can be used to reveal the unconventional phenomena on the solid/liquid interfaces.

Metformin treatment improves the spatial memory of aged mice in an APOE genotype-dependent manner.

Aging and apolipoprotein E4 (ApoE4) can increase the risk of cognitive impairment and neurodegenerative disorders, including Alzheimer's disease (AD), and patients with type 2 diabetes mellitus are highly susceptible to cognitive dysfunction. Recent research has indicated that metformin, a prescribed drug for type 2 diabetes, may affect cognitive function; however, findings regarding its efficacy are largely controversial. The current study reported that a 5-mo metformin administration (300 mg/kg/d) starting at 13 mo old improved the spatial memory of ApoE3-target replacement (TR) mice, not ApoE4-TR mice. It found that in aged ApoE3-TR mice, metformin treatment, at a molecular level, inhibited AMPK activity, increased insulin signaling, and activated mammalian target of rapamycin signaling, resulting in an enhanced expression of postsynaptic proteins; but the response of the neuronal AMPK activity and insulin signaling to metformin was blunt in aged ApoE4-TR mice. Meanwhile, metformin treatment also increased the phosphorylation of tau in both ApoE3-TR and ApoE4-TR mice, implying that metformin may have side effects in human. These findings suggest that metformin can improve the cognitive performance of aged mice in an APOE genotype-dependent manner, which provides empirical insights into the clinical value of metformin for ApoE4- and age-related AD prevention and treatment.-Zhang, J., Lin, Y., Dai, X., Fang, W., Wu, X., Chen, X. Metformin treatment improves the spatial memory of aged mice in an APOE genotype-dependent manner.

The Phase Evolution and Physical Properties of Binary Copper Oxide Thin Films Prepared by Reactive Magnetron Sputtering.

P-type binary copper oxide semiconductor films for various O2 flow rates and total pressures (Pt) were prepared using the reactive magnetron sputtering method. Their morphologies and structures were detected by X-ray diffraction, Raman spectrometry, and SEM. A phase diagram with Cu2O, Cu4O3, CuO, and their mixture was established. Moreover, based on Kelvin Probe Force Microscopy (KPFM) and conductive AFM (C-AFM), by measuring the contact potential difference (VCPD) and the field emission property, the work function and the carrier concentration were obtained, which can be used to distinguish the different types of copper oxide states. The band gaps of the Cu2O, Cu4O3, and CuO thin films were observed to be (2.51 ± 0.02) eV, (1.65 ± 0.1) eV, and (1.42 ± 0.01) eV, respectively. The resistivities of Cu2O, Cu4O3, and CuO thin films are (3.7 ± 0.3) × 10³ Ω·cm, (1.1 ± 0.3) × 10³ Ω·cm, and (1.6 ± 6) × 10¹ Ω·cm, respectively. All the measured results above are consistent.

3D plum candy-like NiCoMnO4@graphene as anodes for high-performance lithium-ion batteries.

3D plum candy-like NiCoMnO4 microspheres have been prepared via ultrasonic spraying and subsequently wrapped by graphene through electrostatic self-assembly. The as-prepared NiCoMnO4 powders show hollow structures and NiCoMnO4@graphene exhibits excellent electrochemical performances in terms of rate performance and cycling stability, achieving a high reversible capacity of 844.6 mA h g-1 at a current density of 2000 mA g-1. After 50 cycles at 1000 mA g-1, NiCoMnO4@graphene delivers a reversible capacity of 1045.1 mA h g-1 while the pristine NiCoMnO4 only has a capacity of 143.4 mA h g-1. The hierarchical porous structure helps to facilitate electron transfer and Li-ion kinetic diffusion by shortening the Li-ion diffusion length, accommodating the mechanical stress and volume change during the Li-ion insertion/extraction processes. Analysis from the electrochemical performances reveals that the enhanced performances could be also attributed to the reduced charge-transfer resistance and enhanced Li-ion diffusion kinetics because of the graphene-coating. Moreover, Schottky electric field, due to the difference in work function between graphene and NiCoMnO4, might be favorable for the redox activity of the NiCoMnO4. In light of the excellent electrochemical performance and simple preparation, we believe that 3D plum candy-like NiCoMnO4@graphene composites are expected to be applied as a promising anode materials for high-performance lithium ion batteries.

[The Optics and Magnetic Properties of Cr Doped ZnO Thin Films].

The precursor solution is sent to the ultrasonic nozzle directly through a needle tube to prepare Zn1-xCrxO (x=0, 0.01, 0.03 and 0.05)films on quartz substratesby ultrasonic spray method. The structures, optical and magnetic properties of the films were measured by X-ray diffracmeter(XRD), scanning electron microscope(SEM), fluorescence spectrometer, ultraviolet-visible light detector, vibrating sample magnetometer (VSM) and so on. The experimental results indicate that, the undopedZnO thin films exhibit the hexagonal wurtzite crystalline structure with a preferential orientation of (002); the Cr doping restrains the preferred orientation of C axis; the average grain sizes of the samples increase withCr doping, and thesize attains the maximum(31.4 nm) when x=3%. The SEMimages show that the Zn1-xCrxO (x=0, 0.01, 0.03 and 0.05) films are grain-like particles. And it exhibits a long strip shape when x=5%. Moreover, the doping of Cr makes the photoluminescence (PL) spectra of Zn1-xCrxO films change evidently. The undoped sample shows an ultraviolet emission peak at 378 nm as well as a defect related green peak at around 550 nm. However, for the doping samples, there is only a wide range of emission peak from 350 to 550 nm. By gaussian fitting，it is found that VZn, Zni and V-Zn defects exist in the Cr doping films, and VZn is largest when x=3%. The band gap increases with the doping of Cr, and reaches the maximum when x=3%. The doping of Cr hasthe band gap of the samples increase, and the band gapreachs themaximum(3.37 eV) when x=3%. Magnetic measured results show that threedoping samples Zn1-xCrxO(x=1%, 3% and 5%) are ferromagnetic at room temperature, and the magnetization of Zn1-xCrxO (x=3%) is the largest, which is corresponding to the most VZn defect. The experimental results also prove the the oretical prediction that the substitutive Cr in the oxidation state of +3 and the neutral Zn vacancy in the ZnO∶Cr sample are the most favorable defect complex to maintain a high stability of ferromagnetic order.