Resonances in ultracold collisions involving heavy molecules are difficult to understand, and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between 23 Na 40 K molecules in the rovibrational ground state and 40 K atoms. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atommolecule Feshbach resonances are identified by observing an enhancement of the loss rate coefficients. We have observed three resonances at approximately 101 G in various atom-molecule scattering channels, with the widths being a few hundred milliGauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with an unprecedented resolution. Our work will help to improve the understanding of complicated ultracold collisions, and open up the possibility of creating ultracold triatomic molecules.Understanding collisions involving molecules at the quantum level has been a long-standing goal in chemical physics [1]. Scattering resonance is one of the most remarkable quantum phenomena and plays a critically important role in the study of collisions. It is very sensitive to both the long-range and short-range parts of the molecule interaction potential, and thus offers a unique probe of the potential energy surface (PES) governing the collision dynamics. Although scattering resonances are well known and have been the main features in ultracold atomic gases and nuclear collisions [2], they have proven challenging to observe in molecule systems. Recently, significant progress has been achieved in experimentally studying resonances in cold molecular collisions involving the light particles, e.g., H 2 , HD molecule or He atom, by means of molecular beam techniques. In the crossed-beam or merged-beam experiments, shape resonances or Feshbach resonances have been observed in atom-molecule chemical reactions [3][4][5][6][7][8], atom-molecule inelastic collisions [9][10][11], and molecule-molecule inelas- * These authors contributed equally to this work. tic collisions [12,13]. However, in these experiments, the collision energies are still high (at Kelvin or sub Kelvin), and thus a few partial waves contribute to the scattering cross sections.Ultracold molecules offer great opportunities to study molecular collisions in the quantum regime. At ultralow temperatures, the de Broglie wavelength of the collision partners is much larger than the range of molecular interaction potential, and only the lowest possible partial wave dominates the collision process [14,15]. Consequently, the collisions at ultracold temperatures are highly quantum mechanical. Due to the anisotropy of the PES, the collisions involving ultracold molecules may support many resonances that are contributed by the rotational and vibrational excited states [16,17]. Therefore, it is expected that scattering resonances can be routinely obse...

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To achieve high ionic conductivity for solid electrolyte, an artificial Li‐rich interface layer of about 60 nm thick has been constructed in polymer‐based poly(ethylene oxide)‐lithium bis(trifluoromethanesulfonyl)imide composite solid electrolyte (briefly noted as PEOm) by adding Li‐based alloys. As revealed by high‐resolution transmission electron microscopy and electron energy loss spectroscopy, an artificial interface layer of amorphous feature is created around the Li‐based alloy particles with the gradient distribution of Li across it. Electrochemical analysis and theoretical modeling demonstrate that the interface layer provides fast ion transport path and plays a key role in achieving high and stable ionic conductivity for PEOm‐Li21Si5 composite solid electrolyte. The PEOm‐5%Li21Si5 composite electrolyte exhibits an ionic conductivity of 3.9 × 10–5 S cm−1 at 30 °C and 5.6 × 10−4 S cm−1 at 45 °C. The LiFePO4 | PEOm‐5%Li21Si5 | Li all‐solid‐state batteries could maintain a stable capacity of 129.2 mA h g−1 at 0.2 C and 30 °C after 100 cycles, and 111.3 mA h g−1 after 200 cycles at 0.5 C and 45 °C, demonstrating excellent cycling stability and high‐rate capability.

Sodium‐ion batteries (SIBs) have attracted much attention due to their abundance, easy accessibility, and low cost. All of these advantages make them potential candidates for large‐scale energy storage. The P2‐type layered transition‐metal oxides (NaxTMO2; TM=Mn, Co, Ni, Ti, Fe, V, Cr, and a mixture of multiple elements) exhibit good Na+ ion conductivity and structural stability, which make them an excellent choice for the cathode materials of SIBs. Herein, the structural evolution, anionic redox reaction, some challenges, and recent progress of NaxTMO2 cathodes for SIBs are reviewed and summarized. Moreover, a detailed understanding of the relationship of chemical components, structures, phase compositions, and electrochemical performance is presented. This Review aims to provide a reference for the development of P2‐type layered transition‐metal oxide cathode materials for SIBs.

are not satisfactory because of the low conductivity of sulfur and extremely dissolving of lithium polysulfide (LPS) in ether-based electrolyte. [8] Adopting the structural carbon materials with abundant pores (e.g., carbon spheres, [9][10][11][12] carbon nanotubes, [13][14][15] graphene [16,17] ) and some metal-based compounds (such as cobalt, [6,18,19] nickel, [21][22][23][24] manganese, [25][26][27][28] iron [29][30][31][32][33][34][35][36][37] ) embedded in carbon host can remarkably improve the electrochemical performance of Li-S batteries. Recently, the researchers have demonstrated that configuring the interlayer between the separator and sulfur cathode is an effective way to alleviate the "shuttle effect" in Li-S redox system. [38][39][40][41][42] To avoid the heavy and large volume of the free-standing interlayer, people have begun to modify the separator with functional materials, such as structural carbon materials [43][44][45][46][47][48] and metal-based compounds. [49,50] As the typical earthabundant, low-cost, and environmentally friendly materials, iron-based compounds have already been widely researched in Li-S batteries. [51][52][53][54] For a long time, the researchers mainly ascribed the enhanced performance of Li-S batteries to strong absorbability of sulfur host materials to LPS (Li 2 S x , x = 1, 2, 4, 6, 8). However, according to the previous researches, [7,20] the binding energy of polar metal-based compounds toward LPS may not the decisive factor; relatively speaking, the catalyst effect of host materials toward LPS plays a leading role in improving the performance of Li-S batteries. Therefore, to better help researchers screen out modified materials suitable for sulfur cathode, it is particularly important to find a "descriptor" that can measure the catalytic ability of sulfur modified materials.Considering these factors, a series of iron-based particles (Fe 3 C@Fe 3 O 4 , Fe 3 O 4 , FeS, and Fe 3 N) embedded in the 3D graphitic carbon material were synthesized as the modified materials for battery separator via a facile two-step method. Among these Fe-based functional materials, the yolk-shell Fe 3 C@Fe 3 O 4 exhibits the best catalytical ability toward LPS in Li-S batteries. By analyzing electronic energy and structure, it has been discovered how the p and d band's center affects the electrochemical performance of Li-S batteries. Not only that, through the ab initio molecular dynamics (AIMD) simulations, it is also observed the dynamic changes of LPS clusters (Li 2 S 6 ) Lithium-sulfur batteries have ultra-high energy density and are considered to be one of the most promising energy storage systems among all battery systems. However, due to various thorny problems, their commercial production has not yet been realized. The current experimental research normally lacks a systematic investigation into the conversion mechanism of the sulfur cathode from the electronic structure level. Actually, there is still a lack of powerful theoretical guidance for the design of high-performance Li-S b...

Chemical reactions at ultracold temperature provide an ideal platform to study chemical reactivity at the fundamental level, and to understand how chemical reactions are governed by quantum mechanics [1][2][3][4].Recent years have witnessed the remarkable progress in studying ultracold chemistry with ultracold molecules [5][6][7][8][9][10][11][12][13][14][15].However, these works were limited to exothermic reactions.The direct observation of state-to-state ultracold endothermic reaction remains elusive. Here we report on the investigation of endothermic and nearly thermoneutral atom-exchange reactions in an ultracold atom-dimer mixture. By developing an indirect reactant-preparation method based on a molecular bound-bound transition, we are able to directly observe a universal endothermic reaction with tunable energy threshold and study the state-to-state reaction dynamics. The reaction rate coefficients show a strikingly threshold phenomenon. The influence of the reverse reaction on the reaction dynamics is observed for the endothermic and nearly thermoneutral reactions. We carry out zerorange quantum mechanical scattering calculations to obtain the reaction rate coefficients, and the three-body parameter is determined by comparison with the experiments. The observed endothermic and nearly thermoneutral reaction may be employed to implement collisional Sisyphus cooling of molecules [16], study the chemical reactions in degenerate quantum gases [17,18] and conduct quantum simulation of Kondo effect with ultracold atoms [19,20].

In this study, we isolated and characterized bacterial strains from ancient (Neogene) permafrost sediment that was permanently frozen for 3.5 million years. The sampling site was located at Mammoth Mountain in the Aldan river valley in Central Yakutia in Eastern Siberia. Analysis of phospolipid fatty acids (PLFA) demonstrated the dominance of bacteria over fungi; the analysis of fatty acids specific for Gram-positive and Gram-negative bacteria revealed an approximately twofold higher amount of Gram-negative bacteria compared to Gram-positive bacteria. Direct microbial counts after natural permafrost enrichment showed the presence of (4.7 ± 1.5) × 108 cells g−1 sediment dry mass. Viable heterotrophic bacteria were found at 0 °C, 10 °C and 25 °C, but not at 37 °C. Spore-forming bacteria were not detected. Numbers of viable fungi were low and were only detected at 0 °C and 10 °C. Selected culturable bacterial isolates were identified as representatives of Arthrobacter phenanthrenivorans, Subtercola frigoramans and Glaciimonas immobilis. Representatives of each of these species were characterized with regard to their growth temperature range, their ability to grow on different media, to produce enzymes, to grow in the presence of NaCl, antibiotics, and heavy metals, and to degrade hydrocarbons. All strains could grow at −5 °C; the upper temperature limit for growth in liquid culture was 25 °C or 30 °C. Sensitivity to rich media, antibiotics, heavy metals, and salt increased when temperature decreased (20 °C > 10 °C > 1 °C). In spite of the ligninolytic activity of some strains, no biodegradation activity was detected.