Surface Stabilization of O3-type Layered Oxide Cathode to Protect the Anode of Sodium Ion Batteries for Superior Lifespan

Even though the energy density of O3-type layer-structured metal oxide cathode can fully reach the requirement for large-scale energy storage systems, the cycling lifespan still cannot meet the demand for practical application once it is coupled with a non-sodium-metal anode in full-cell system. Transition metal dissolution into the electrolyte occurs along with continuous phase transformation and accelerates deterioration of the crystal structure, followed by migration and finally deposition on the anode to form a vicious circle. Surface engineering techniques are employed to modify the interface between active materials and the electrolyte by coating them with a thin layer of AlPO4 ion conductor. This stable thin layer can stabilize the surface crystal structure of the cathode material by avoiding element dissolution. Meanwhile, it can protect the anode from increased resistance by suppressing the dissolution-migration-deposition process. This technique is a promising method to improve the lifetime for the future commercialization

2-Chloro-N-(3-methyl­phen­yl)acetamide

The conformation of the N—H bond in the structure of the title compound, C9H10ClNO, is syn to the meta-methyl group, in contrast to the anti conformation observed with respect to the meta-nitro group in 2-chloro-N-(3-nitro­phen­yl)­acetamide. The asymmetric unit of the title compound contains two mol­ecules. The geometric parameters of the title compound are similar to those of 2-chloro-N-(4-methyl­phen­yl)­acetamide, 2-chloro-N-(3-nitro­phen­yl)acetamide and other acetanilides. Dual inter­molecular N—H⋯O hydrogen bonds link the mol­ecules in the direction of the a axis

A Versatile Method of Engineering the Electron Wavefunction of Hybrid Quantum Devices

With the development of quantum technology, hybrid devices that combine superconductors (S) and semiconductors (Sm) have attracted great attention due to the possibility of engineering structures that benefit from the integration of the properties of both materials. However, until now, none of the experiments have reported good control of band alignment at the interface, which determines the strength of S-Sm coupling and the proximitized superconducting gap. Here, we fabricate hybrid devices in a generic way with argon milling to modify the interface while maintaining its high quality. First, after the milling the atomically connected S-Sm interfaces appear, resulting in a large induced gap, as well as the ballistic transport revealed by the multiple Andreev reflections and quantized above-gap conductance plateaus. Second, by comparing transport measurement with Schr\"odinger-Poisson (SP) calculations, we demonstrate that argon milling is capable of varying the band bending strength in the semiconducting wire as the electrons tend to accumulate on the etched surface for longer milling time. Finally, we perform nonlocal measurements on advanced devices to demonstrate the coexistence and tunability of crossed Andreev reflection (CAR) and elastic co-tunneling (ECT) -- key ingredients for building the prototype setup for realization of Kitaev chain and quantum entanglement probing. Such a versatile method, compatible with the standard fabrication process and accompanied by the well-controlled modification of the interface, will definitely boost the creation of more sophisticated hybrid devices for exploring physics in solid-state systems.Comment: 18 pages, 9 figure

Organic Single-Crystalline Donor-Acceptor Heterojunctions with Ambipolar Band-Like Charge Transport for Photovoltaics

Solution-processed organic single-crystalline donor-acceptor heterojunctions (SCHJs) composed of N,N,N',N'-tetraphenylbenzidine (TPB) and phenyl-C61-butyric acid methyl ester ([60]PCBM) were successfully obtained and fundamental studies on its charge transport properties were demonstrated; Revealing the advantages of applying single-crystalline heterojunctions in photovoltaic devices. The SCHJs exhibited a balanced high-mobility ambipolar charge transport with both hole and electron mobility being more than one order magnitude higher than its thin-film heterojunction (TFHJ) counterparts. The difference between single-crystalline and thin-film heterojunctions in charge transport mechanisms was revealed, and we showed that SCHJs present a more favorable band-like charge transport properties at room temperature. Organic photovoltaics fabricated on SCHJs present much higher current density and a 32-times higher PCE than thin-film heterojunction devices. The present work, which outlined comprehensive advantages of single-crystalline heterojunctions in charge transport properties, should accelerate the application of organic single crystals for high performance photovoltaics

Dual-comb spectroscopy over 100km open-air path

Satellite-based greenhouse gases (GHG) sensing technologies play a critical role in the study of global carbon emissions and climate change. However, none of the existing satellite-based GHG sensing technologies can achieve the measurement of broad bandwidth, high temporal-spatial resolution, and high sensitivity at the same time. Recently, dual-comb spectroscopy (DCS) has been proposed as a superior candidate technology for GHG sensing because it can measure broadband spectra with high temporal-spatial resolution and high sensitivity. The main barrier to DCS's display on satellites is its short measurement distance in open air achieved thus far. Prior research has not been able to implement DCS over 20 km of open-air path. Here, by developing a bistatic setup using time-frequency dissemination and high-power optical frequency combs, we have implemented DCS over a 113 km turbulent horizontal open-air path. Our experiment successfully measured GHG with 7 nm spectral bandwidth and a 10 kHz frequency and achieved a CO2 sensing precision of <2 ppm in 5 minutes and <0.6 ppm in 36 minutes. Our results represent a significant step towards advancing the implementation of DCS as a satellite-based technology and improving technologies for GHG monitoringComment: 24 pages, 6 figure

Pairing symmetry and properties of iron-based high temperature superconductors

Pairing symmetry is important to indentify the pairing mechanism. The analysis becomes particularly timely and important for the newly discovered iron-based multi-orbital superconductors. From group theory point of view we classified all pairing matrices (in the orbital space) that carry irreducible representations of the system. The quasiparticle gap falls into three categories: full, nodal and gapless. The nodal-gap states show conventional Volovik effect even for on-site pairing. The gapless states are odd in orbital space, have a negative superfluid density and are therefore unstable. In connection to experiments we proposed possible pairing states and implications for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio