Alloy anodes are promising anode materials for lithium-ion batteries due to their high-energy capacity and safety characteristics. However, the commercial use of alloy anodes has been hindered to ...date by their low cycle life and high initial capacity loss. This review highlights the recent progress in improving and understanding the electrochemical performance of various alloy anodes. The approaches used for performance improvement are summarized, and the causes of first-cycle irreversible capacity loss are discussed. The capacity retentions and irreversible capacity losses of various alloy anodes are compared. Several alloy anodes exhibited excellent cycle life (up to 300 cycles) with high initial coulombic efficiency (80–90%) and large reversible capacity (500–700
mAh
g
−1).
▶ The phase transformation and performance of LiFePO4 materials are reviewed. ▶ Carbon coating is more critical than doping and particle size control. ▶ Iron deposit on graphite anode leads to ...capacity degradation. ▶ Low temperature performance can be improved by electrolyte modification.
LiFePO4 has been considered a promising battery material in electric vehicles. However, there are still a number of technical challenges to overcome before its wide-spread applications. In this article, the structure and electrochemical performance of LiFePO4 are reviewed in light of the major technical requirements for EV batteries. The rate capability, capacity density, cyclic life and low-temperature performance of various LiFePO4 materials are described. The major factors affecting these properties are discussed, which include particle size, doping, carbon coating, conductive carbon loading and synthesis techniques. Important future research for science and engineering is suggested.
The detection of gravitational waves (GWs) provides a direct way to measure the luminosity distance, which enables us to probe cosmology. In this paper, we continue to expand the application of GW ...standard sirens in cosmology, and propose that the spatial curvature can be estimated in a model-independent way by comparing the distances from future GW sources and current cosmic-chronometer observations. We expect an electromagnetic counterpart of the GW event to give the source redshift, and simulate hundreds of GW data from the coalescence of double neutron stars and black hole-neutron star binaries using the Einstein Telescope as a reference. Our simulations show that, from 100 simulated GW events and 31 current cosmic-chronometer measurements, the error of the curvature parameter K is expected to be constrained at the level of ∼0.125. If 1000 GW events were observed, the uncertainty of K would be further reduced to ∼0.040. We also find that adding 50 mock H(z) data points (consisting of 81 cosmic-chronometer data points and 1000 simulated GW events) could result in a much tighter constraint on the zero cosmic curvature, for which K = −0.002 0.028. Compared to some actual model-independent curvature tests involving distances from other cosmic probes, this method using GW data achieves constraints with much higher precision.
Measurement-device-independent quantum key distribution (MDI QKD) removes all detector side channels and enables secure QKD with an untrusted relay. It is suitable for building a star-type quantum ...access network, where the complicated and expensive measurement devices are placed in the central untrusted relay and each user requires only a low-cost transmitter, such as an integrated photonic chip. Here, we experimentally demonstrate a 1.25-GHz silicon photonic chip-based MDI QKD system using polarization encoding. The photonic chip transmitters integrate the necessary encoding components for a standard QKD source. We implement random modulations of polarization states and decoy intensities, and demonstrate a finite-key secret rate of31bit/sover 36-dB channel loss (or 180-km standard fiber). This key rate is higher than state-of-the-art MDI QKD experiments. The results show that silicon photonic chip-based MDI QKD, benefiting from miniaturization, low-cost manufacture, and compatibility with CMOS microelectronics, is a promising solution for future quantum secure networks.
The development of energy‐storage devices has received increasing attention as a transformative technology to realize a low‐carbon economy and sustainable energy supply. Lithium–sulfur (Li–S) ...batteries are considered to be one of the most promising next‐generation energy‐storage devices due to their ultrahigh energy density. Despite the extraordinary progress in the last few years, the actual energy density of Li–S batteries is still far from satisfactory to meet the demand for practical applications. Considering the sulfur electrochemistry is highly dependent on solid‐liquid‐solid multi‐phase conversion, the electrolyte amount plays a primary role in the practical performances of Li–S cells. Therefore, a lean electrolyte volume with low electrolyte/sulfur ratio is essential for practical Li–S batteries, yet under these conditions it is highly challenging to achieve acceptable electrochemical performances regarding sulfur kinetics, discharge capacity, Coulombic efficiency, and cycling stability especially for high‐sulfur‐loading cathodes. In this Review, the impact of the electrolyte/sulfur ratio on the actual energy density and the economic cost of Li–S batteries is addressed. Challenges and recent progress are presented in terms of the sulfur electrochemical processes: the dissolution–precipitation conversion and the solid–solid multi‐phasic transition. Finally, prospects of future lean‐electrolyte Li–S battery design and engineering are discussed.
Lean on me: The challenges, recent progress, and perspectives for lean‐electrolyte Li–S batteries are discussed in terms of the two electrochemical processes for sulfur, that is, the dissolution–precipitation conversion and the solid–solid pathway.
Abstract Polyimide (PI) has excellent resistance to high or low temperatures due to its unique molecular structure, and is widely used in advanced electronics and power systems in extreme ...environments. In recent years, a small amount of studies have been published to modulate the dynamic behavior of PI such as self‐healable, recyclable, and degradable abilities by adjusting the structure of molecular chains and the composition of monomers. However, the conceptual design, formation conditions, and application prospects of dynamic PI are still unclear. In this paper, the new concepts and systems of dynamic PI are introduced from the perspective of the design of molecular structure, the development of regulating performance area, and the application of extreme insulation, based on recent work and other representative work. Specifically, this work appeals to researchers involved in PI synthesis, smart, dielectric, energy storage, and extreme insulation.
Rhodium(III) catalysis has enabled a plethora of oxidative C−H functionalizations, which predominantly employ stoichiometric amounts of toxic and/or expensive metal oxidants. In contrast, we herein ...describe the first electrochemical rhodium‐catalyzed C−H activation that avoids hazardous chemical oxidants. Environmentally benign twofold C−H/C−H functionalizations were accomplished with weakly coordinating benzoic acids and benzamides, employing electricity as the terminal oxidant and generating H2 as the sole byproduct.
Elect(Rh)odium: Electrochemical twofold C−H functionalizations of weakly coordinating benzoic acids and benzamides were accomplished by rhodium(III) catalysis with electricity as a sustainable oxidant and the generation of H2 as the sole byproduct.
The advent of 3D printing brought about the possibilities of microlattice metamaterials as advanced materials with the potentials to surpass the functionalities of traditional materials. Sound ...absorbing materials which are also tough and lightweight are of particular importance as practical engineering materials. There are however a lack of attempts on the study of metamaterials multifunctional for both purposes. Herein, we present four types of face‐centered cubic based plate and truss microlattices as novel metamaterials with simultaneous excellent sound and mechanical energy absorption performance. High sound absorption coefficients nearing 1 and high specific energy absorption of 50.3 J g−1 have been measured. Sound absorption mechanisms of microlattices are proposed to be based on a “cascading resonant cells theory”, an extension of the Helmholtz resonance principle that we have conceptualized herein. Characteristics of absorption coefficients are found to be essentially geometry limited by the pore and cavity morphologies. The excellent mechanical properties in turn derive from both the approximate membrane stress state of the plate architecture and the excellent ductility and strength of the base material. Overall, this work presents a new concept on the specific structural design and materials selection for architectured metamaterials with dual sound and mechanical energy absorption capabilities.
Simultaneous sound and mechanical energy absorbing microlattice metamaterials are presented in this work. High sound absorption coefficients up to 1 are measured with mechanisms deriving from the Helmholtz resonance principle. High specific energy absorption up to 50.3 J g−1 in turn is derived from the high strength plate morphology and membrane stress states of the microlattice architecture.
Glutamate-gated AMPA receptors mediate the fast component of excitatory signal transduction at chemical synapses throughout all regions of the mammalian brain. AMPA receptors are tetrameric ...assemblies composed of four subunits, GluA1-GluA4. Despite decades of study, the subunit composition, subunit arrangement, and molecular structure of native AMPA receptors remain unknown. Here we elucidate the structures of 10 distinct native AMPA receptor complexes by single-particle cryo-electron microscopy (cryo-EM). We find that receptor subunits are arranged nonstochastically, with the GluA2 subunit preferentially occupying the B and D positions of the tetramer and with triheteromeric assemblies comprising a major population of native AMPA receptors. Cryo-EM maps define the structure for S2-M4 linkers between the ligand-binding and transmembrane domains, suggesting how neurotransmitter binding is coupled to ion channel gating.
Estuaries are a major boundary in the land-ocean interaction zone where organic carbon (OC) and nutrients are being processed, resulting in a high water-to-air carbon dioxide (CO2) flux ...(approximately 0.25 Pg C y(-1)). The continental shelves, however, take up CO2 (approximately 0.25 Pg C y(-1)) from the atmosphere, accounting for approximately 17% of open ocean CO2 uptake (1.5 Pg Cy(-1)). It is demonstrated here that CO2 release in estuaries is largely supported by microbial decomposition of highly productive intertidal marsh biomass. It appears that riverine OC, however, would bypass the estuarine zone, because of short river-transit times, and contribute to carbon cycling in the ocean margins and interiors. Low-latitude ocean margins release CO2 because they receive two-thirds of the terrestrial OC. Because of recent CO2 increase in the atmosphere, CO2 releases from low latitudes have become weaker and CO2 uptake by mid- and high-latitude shelves has become stronger, thus leading to more dissolved inorganic carbon export to the ocean.
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