It is challenging to develop alloying anodes with ultrafast charging and large energy storage using bulk anode materials because of the difficulty of carrier‐ion diffusion and fragmentation of the ...active electrode material. Herein, a rational strategy is reported to design bulk Bi anodes for Na‐ion batteries that feature ultrafast charging, long cyclability, and large energy storage without using expensive nanomaterials and surface modifications. It is found that bulk Bi particles gradually transform into a porous nanostructure during cycling in a glyme‐based electrolyte, whereas the resultant structure stores Na ions by forming phases with high Na diffusivity. These features allow the anodes to exhibit unprecedented electrochemical properties; the developed Na–Bi half‐cell delivers 379 mA h g−1 (97% of that measured at 1C) at 7.7 A g−1 (20C) during 3500 cycles. It also retained 94% and 93% of the capacity measured at 1C even at extremely fast‐charging rates of 80C and 100C, respectively. The structural origins of the measured properties are verified by experiments and first‐principles calculations. The findings of this study not only broaden understanding of the underlying mechanisms of fast‐charging anodes, but also provide basic guidelines for searching battery anodes that simultaneously exhibit high capacities, fast kinetics, and long cycling stabilities.
With the difficulty in simultaneously achieving a large capacity, ultrafast charging capability, and long cycling stability in a battery anode, a bulk Bi anode is presented for Na‐ion batteries that provides a simple yet practical route to address this issue without using expensive nanoscale materials and additional complex modifications.
In this study, we evaluated accumulation and adverse effects of ingestion of microplastics in the monogonont rotifer (Brachionus koreanus). The dependence of microplastic toxicity on particle size ...was investigated by measuring several in vivo end points and studying the ingestion and egestion using 0.05-, 0.5-, and 6-μm nonfunctionalized polystyrene microbeads. To identify the defense mechanisms activated in response to microplastic exposure, the activities of several antioxidant-related enzymes and the phosphorylation status of mitogen-activated protein kinases (MAPKs) were determined. Exposure to polystyrene microbeads of all sizes led to significant size-dependent effects, including reduced growth rate, reduced fecundity, decreased lifespan and longer reproduction time. Rotifers exposed to 6-μm fluorescently labeled microbeads exhibited almost no fluorescence after 24 h, while rotifers exposed to 0.05- and 0.5-μm fluorescently labeled microbeads displayed fluorescence until 48 h, suggesting that 6-μm microbeads are more effectively egested from B. koreanus than 0.05- or 0.5-μm microbeads. This observation provides a potential explanation for our findings that microbead toxicity was size-dependent and smaller microbeads were more toxic. In vitro tests revealed that antioxidant-related enzymes and MAPK signaling pathways were significantly activated in response to microplastic exposure in a size-dependent manner.
Perovskite solar cells (PSCs) based on organic monovalent cation (methylammonium or formamidinium) have shown excellent optoelectronic properties with high efficiencies above 22%, threatening the ...status of silicon solar cells. However, critical issues of long‐term stability have to be solved for commercialization. The severe weakness of the state‐of‐the‐art PSCs against moisture originates mainly from the hygroscopic organic cations. Here, rubidium (Rb) is suggested as a promising candidate for an inorganic–organic mixed cation system to enhance moisture‐tolerance and photovoltaic performances of formamidinium lead iodide (FAPbI3). Partial incorporation of Rb in FAPbI3 tunes the tolerance factor and stabilizes the photoactive perovskite structure. Phase conversion from hexagonal yellow FAPbI3 to trigonal black FAPbI3 becomes favored when Rb is introduced. The authors find that the absorbance and fluorescence lifetime of 5% Rb‐incorporated FAPbI3 (Rb0.05FA0.95PbI3) are enhanced than bare FAPbI3. Rb0.05FA0.95PbI3‐based PSCs exhibit a best power conversion efficiency of 17.16%, which is much higher than that of the FAPbI3 device (13.56%). Moreover, it is demonstrated that the Rb0.05FA0.95PbI3 film shows superior stability against high humidity (85%) and the full device made with the mixed perovskite exhibits remarkable long‐term stability under ambient condition without encapsulation, retaining the high performance for 1000 h.
Partial substitution of inorganic rubidium cation (Rb+) for formamidinium lead iodide (FAPbI3) perovskite suppresses nonperovskite phase formation and increases fluorescence lifetime. Introduction of the smaller monovalent cation in FAPbI3 renders the perovskite more tolerant to high humidity. These lead to enhanced photovoltaic performances and long‐term stability of perovskite solar cells based on Rb‐mixed FAPbI3.
Lead halide perovskite solar cells (PSCs) are thought to be promising energy power suppliers because of their feasibility for high power conversion efficiency (PCE), light weight, and flexible ...architecture. The preparation of charge transporting layers at low temperature has been essential for high-performance and flexible PSCs. Recently, low-temperature-processed metal oxides have been a desirable material for charge transport and air stability for PSCs, instead of organic semiconductors. However, pristine metal oxides fabricated at low temperature have still precluded high performance of the device because of their low conductivity and large deviation in energy levels from the conduction band or valance band of the perovskite. Therefore, doping metals in the metal oxides has been considered as an effective method to endow suitable electrical properties. Herein, we developed a highly efficient electron transporting layer (ETL) comprising Li-doped SnO2 (Li:SnO2) prepared at low temperature in solution. The doped Li in SnO2 enhanced conductivity as well as induced a downward shift of the conduction band minimum of SnO2, which facilitated injection and transfer of electrons from the conduction band of the perovskite. The PCE was measured to be 18.2% and 14.78% for the rigid and flexible substrates, respectively. The high-performance and flexible PSCs could be potentially used as a wearable energy power source.
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•Li:SnO2 and SnO2 are used as an electron transporting layer in perovskite solar cells.•The performance of the devices is enhanced after Li-doping in SnO2.•Low-temperature and solution process realize high-performance wearable perovskite solar cells.
The development of energy‐efficient artificial synapses capable of manifoldly tuning synaptic activities can provide a significant breakthrough toward novel neuromorphic computing technology. Here, a ...new class of artificial synaptic architecture, a three‐terminal device consisting of a vertically integrated monolithic tungsten oxide memristor, and a variable‐barrier tungsten selenide/graphene Schottky diode, termed as a ‘synaptic barrister,’ are reported. The device can implement essential synaptic characteristics, such as short‐term plasticity, long‐term plasticity, and paired‐pulse facilitation. Owing to the electrostatically controlled barrier height in the ultrathin van der Waals heterostructure, the device exhibits gate‐controlled memristive switching characteristics with tunable programming voltages of 0.2−0.5 V. Notably, by electrostatic tuning with a gate terminal, it can additionally regulate the degree and tuning rate of the synaptic weight independent of the programming impulses from source and drain terminals. Such gate tunability cannot be accomplished by previously reported synaptic devices such as memristors and synaptic transistors only mimicking the two‐neuronal‐based synapse. These capabilities eventually enable the accelerated consolidation and conversion of synaptic plasticity, functionally analogous to the synapse with an additional neuromodulator in biological neural networks.
A synaptic barristor, an artificial synaptic architecture formed by monolithically integrating a memristor and a barristor using phase‐engineered 2D heterostructures, is presented. This three‐terminal artificial synapse could implement fundamental synaptic functions with external gate controllability. Such unique capabilities enable the accelerated consolidation and conversion of synaptic plasticity, functionally analogous to the synapse with an additional neuromodulator in biological neural networks.
Unit‐cell‐thick MoS2 is a promising electrocatalyst for the hydrogen evolution reaction (HER) owing to its tunable catalytic activity, which is determined based on the energetics and molecular ...interactions of different types of HER active sites. Kinetic responses of MoS2 active sites, including the reaction onset, diffusion of the electrolyte and H2 bubbles, and continuation of these processes, are important factors affecting the catalytic activity of MoS2. Investigating these factors requires a direct real‐time analysis of the HER occurring on spatially independent active sites. Herein, the H2 evolution and electrolyte diffusion on the surface of MoS2 are observed in real time by in situ electrochemical liquid‐phase transmission electron microscopy (LPTEM). Time‐dependent LPTEM observations reveal that different types of active sites are sequentially activated under the same conditions. Furthermore, the electrolyte flow to these sites is influenced by the reduction potential and site geometry, which affects the bubble detachment and overall HER activity of MoS2.
In situ electrochemical liquid‐phase transmission electron microscopy (LPTEM) facilitates real‐time observation of the H2 evolution reaction (HER) on MoS2 monolayer. Time‐series LPTEM shows sequential activation, H2 bubble formation, and electrolyte flow on different types of catalytic active sites. Directionality of H2 bubbling and competitive wetting between the bubbles and electrolyte on catalyst surface significantly affect the HER activity of the active sites.
•Lipids are an essential cellular component for maintaining homeostasis in the presence of environmental stressors.•Lipid homeostasis can be modulated by environmental stressors.•Understanding ...mechanisms that protect against stressors is important with regard to aquatic invertebrates.•Various environmental stressors affect life cycles and lipid homeostasis in aquatic invertebrates.•Omics approaches have been used but there are still gaps in our knowledge on aquatic invertebrates as well as the lipidome.
Lipid metabolism is crucial for the survival and propagation of the species, since lipids are an essential cellular component across animal taxa for maintaining homeostasis in the presence of environmental stressors. This review aims to summarize information on the lipid metabolism under environmental stressors in aquatic invertebrates. Fatty acid synthesis from glucose via de novo lipogenesis (DNL) pathway is mostly well-conserved across animal taxa. The structure of free fatty acid (FFA) from both dietary and DNL pathway could be transformed by elongase and desaturase. In addition, FFA can be stored in lipid droplet as triacylglycerol, upon attachment to glycerol. However, due to the limited information on both gene and lipid composition, in-depth studies on the structural modification of FFA and their storage conformation are required. Despite previously validated evidences on the disturbance of the normal life cycle and lipid homeostasis by the environmental stressors (e.g., obesogens, salinity, temperature, pCO2, and nutrients) in the aquatic invertebrates, the mechanism behind these effects are still poorly understood. To overcome this limitation, omics approaches such as transcriptomic and proteomic analyses have been used, but there are still gaps in our knowledge on aquatic invertebrates as well as the lipidome. This paper provides a deeper understanding of lipid metabolism in aquatic invertebrates.
Microplastic pollution causes a major concern in the marine environment due to their worldwide distribution, persistence, and adverse effects of these pollutants in the marine ecosystem. Despite its ...global presence, there is still a lack of information on the effect of microplastics on marine organisms at the molecular level. Herein we demonstrated ingestion and egestion of nano- (0.05 μm) and micro-sized (0.5 and 6 μm) polystyrene microbeads in the marine copepod Paracyclopina nana, and examined molecular responses to exposure to microbeads with in vivo endpoints such as growth rate and fecundity. Also, we proposed an adverse outcome pathway for microplastic exposure that covers molecular and individual levels. This study provides the first insight into the mode of action in terms of microplastic-induced oxidative stress and related signaling pathways in P. nana.
NF‐κB essential modulator (NEMO) is a key regulatory protein that functions during NF‐κB‐ and interferon‐mediated signaling in response to extracellular stimuli and pathogen infections. Tight ...regulation of NEMO is essential for host innate immune responses and for maintenance of homeostasis. Here, we report that the E3 ligase MARCH2 is a novel negative regulator of NEMO‐mediated signaling upon bacterial or viral infection. MARCH2 interacted directly with NEMO during the late phase of infection and catalyzed K‐48‐linked ubiquitination of Lys326 on NEMO, which resulted in its degradation. Deletion of MARCH2 resulted in marked resistance to bacterial/viral infection, along with increased innate immune responses both in vitro and in vivo. In addition, MARCH2−/− mice were more susceptible to LPS challenge due to massive production of cytokines. Taken together, these findings provide new insight into the molecular regulation of NEMO and suggest an important role for MARCH2 in homeostatic control of innate immune responses.
Synopsis
NEMO/IKKγ plays a key role in regulating both the NF‐κB and type I IFN signaling pathways. Here, E3 ubiquitin ligase MARCH2 is shown to catalyze Lys48‐linked polyubiqutination and degradation of NEMO/IKKγ, thereby negatively regulates the innate immune response to viral and bacterial infection.
MARCH2−/− mice are more resistant to viral and bacterial infection.
MARCH2 specifically interact with NEMO/IKKγ upon viral and bacterial infection.
MARCH2 catalyzes the K48‐linked polyubiquitination of Lys326 on NEMO/IKKγ.
MARCH2 interacts with the NF‐κB modulator NEMO and initiates its ubiquitin‐dependent degradation for homeostatic control of innate immune responses to viral and bacterial infection.
A gate stack that facilitates a high‐quality interface and tight electrostatic control is crucial for realizing high‐performance and low‐power field‐effect transistors (FETs). However, when ...constructing conventional metal‐oxide‐semiconductor structures with two‐dimensional (2D) transition metal dichalcogenide channels, achieving these requirements becomes challenging due to inherent difficulties in obtaining high‐quality gate dielectrics through native oxidation or film deposition. Here, a gate‐dielectric‐less device architecture of van der Waals Schottky gated metal–semiconductor FETs (vdW‐SG MESFETs) using a molybdenum disulfide (MoS2) channel and surface‐oxidized metal gates such as nickel and copper is reported. Benefiting from the strong SG coupling, these MESFETs operate at remarkably low gate voltages, <0.5 V. Notably, they also exhibit Boltzmann‐limited switching behavior featured by a subthreshold swing of ≈60 mV dec−1 and negligible hysteresis. These ideal FET characteristics are attributed to the formation of a Fermi‐level (EF) pinning‐free gate stack at the Schottky–Mott limit. Furthermore, authors experimentally and theoretically confirm that EF depinning can be achieved by suppressing both metal‐induced and disorder‐induced gap states at the interface between the monolithic‐oxide‐gapped metal gate and the MoS2 channel. This work paves a new route for designing high‐performance and energy‐efficient 2D electronics.
Herein, van der Waals Schottky‐gated MoS2 metal–semiconductor field‐effect transistors are developed, mitigating two primary sources of Fermi‐level pinning—metal‐induced gap states and disorder‐induced gap states. Consequently, the devices exhibit ideal hysteresis‐free transistor characteristics with a subthreshold swing of 60 mV dec−1 at 300 K, approaching to the fundamental Boltzmann switching limit.
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