MnFe Prussian Blue Analogue Open Cages for Sodium-Ion Batteries: Simultaneous Evolution of Structure, Morphology, and Energy Storage Properties.

Prussian blue analogues (PBAs) exhibiting hollow morphologies have garnered considerable attention owing to their remarkable electrochemical properties. In this study, a one-pot strategy is proposed for the synthesis of MnFe PBA open cages. The materials are subsequently employed as cathode electrode in sodium-ion batteries (SIBs). The simultaneous evolution of structure, morphology, and performance during the synthesis process is investigated. The findings reveal substantial structural modifications as the reaction time is prolonged. The manganese content in the samples diminishes considerably, while the potassium content experiences an increase. This compositional variation is accompanied by a significant change in the spin state of the transition metal ions. These structural transformations trigger the occurrence of the Kirkendall effect and Oswald ripening, culminating in a profound alteration of the morphology of MnFe PBA. Moreover, the shifts in spin states give rise to distinct changes in their charge-discharge profiles and redox potentials. Furthermore, an exploration of the formation conditions of the samples and their variations before and after cycling is conducted. This study offers valuable insights into the intricate relationship between the structure, morphology, and electrochemical performance of MnFe PBA, paving the way for further optimizations in this promising class of materials for energy storage applications.

Weakly Solvating Ether-Based Electrolyte Constructing Anion-Derived Solid Electrolyte Interface in Graphite Anode toward High-Stable Potassium-Ion Batteries.

Low-cost graphite has emerged as the most promising anode material for potassium-ion batteries (PIBs). Constructing the inorganic-rich solid electrolyte interface (SEI) on the surface of graphite anode is crucial for achieving superior electrochemical performance of PIBs. However, the compositions of SEI formed by conventional strongly solvating electrolytes are mainly organic, leading to the SEI structure being thick and causing the co-intercalation behavior of ions with the solvent. Herein, a weakly solvating electrolyte is applied to weaken the cation-solvent interaction and alter the cation solvation sheath structures, conducing to the inorganic composition derived from anions also participating in the formation of SEI, together with forming a uniformly shaped SEI with superior mechanical properties, and thus improving the overall performance of PIBs. The electrolyte solvation structure rich in aggregated ion pairs (AGGs) (69%) enables remarkable potassium-ion intercalation behavior at the graphite anode (reversible capacity of 269 mAh g-1) and highly stable plating/stripping of potassium metal anode (96.5%). As a practical device application, the assembled potassium-ion full-battery (PTCDA//Graphite) displays superior cycle stability. The optimizing strategy of cation solvation sheath structures offers a promising approach for developing high-performance electrolytes and beyond.

Molecular Engineering Chemical Pre-lithiation Reagent with Low Redox Potential for Graphite Anode Enables High Coulombic Efficiency.

Graphite (Gr) is a low-cost and high-stability anode for lithium-ion batteries (LIBs). However, Gr anode exhibits an obstinate drawback of low initial Coulombic efficiency (ICE), owing to the active lithium loss for the solid electrolyte interphase (SEI) layer. Herein, a straightforward and effective chemical pre-lithiation strategy is proposed to compensate for the lithium loss. A molecular engineering phenanthrene-based lithium-arene complex (Ph-based LAC) reagent is designed by density functional theory (DFT) calculations. The engineering Ph-based reagent enhances the stability of the π-electron system and the electron-donating capacity, resulting in a reduced redox potential to facilitate lithium transfer. The electrochemical distinct of the Ph-based reagent is illustrated, the prelithiation process in a low Li-insertion platform, and the lithiation degree is controllable with the dipping time (ICE = 102%, 3 min). Notably, a denser and homogeneous SEI layer has pre-formed to enhance the Li+ transport and interface stability. Moreover, the lithium-ion full batteries assemble with LiFePO4 and NCM811 cathode, which exhibits high ICE (96.5% and 90.3%) and energy density (310 and 333 Wh kg-1). These findings present a facile and controllable pre-lithiation strategy to compensate for the lithium of LIBs, providing new valuable insights into the design and optimization of battery manufacture.

In Situ Defect Engineering in Carbon by Atomic Self-Activation to Boost the Accessible Low-Voltage Insertion for Advanced Potassium-Ion Full-Cells.

Enhancing the low-potential capacity of anode materials is significant in boosting the operating voltage of full-cells and constructing high energy-density energy storage devices. Graphitic carbons exhibit outstanding low-potential potassium storage performance, but show a low K+ diffusion kinetics. Herein, in situ defect engineering in graphitic nanocarbon is achieved by an atomic self-activation strategy to boost the accessible low-voltage insertion. Graphitic carbon layers grow on nanoscale-nickel to form the graphitic nanosphere with short-range ordered microcrystalline due to nickel graphitization catalyst. Meanwhile, the widely distributed K+ in the precursor induces the activation of surrounding carbon atoms to in situ generate carbon vacancies as channels. The graphite microcrystals with defect channels realize reversible K+ intercalation at low-potential and accessible ion diffusion kinetics, contributing to high reversible capacity (209 mAh g-1 at 0.05 A g-1 under 0.8 V) and rate capacity (103.2 mAh g-1 at 1 A g-1). The full-cell with Prussian blue cathode and graphitic nanocarbon anode maintains an obvious working platform at ca. 3.0 V. This work provides a strategy for the in situ design of carbon anode materials and gives insights into the potassium storage mechanism at low-potential for high-performance full-cells.

A cubic perovskite fluoride anode with the surface conversion reactions dominated mechanism for advanced lithium-ion batteries.

Perovskite fluorides are attractive anode materials for lithium-ion batteries (LIBs) because of their three-dimensional diffusion channels and robust structures, which are advantageous for the rapid transmission of lithium ions. Unfortunately, the wide band gap results in poor electronic conductivity, which limits their further development and application. Herein, the cubic perovskite iron fluoride (KFeF3, KFF) nanocrystals (∼100 nm) are synthesized by a one-step solvothermal strategy. Thanks to the good electrical conductivity of carbon nanotubes (CNTs), the overall electrochemical performance of composite anode material (KFF-CNTs) has been significantly improved. In particular, the KFF-CNTs deliver a high specific capacity (363.8 mAh g-1), good rate performance (131.6 mAh g-1at 3.2 A g-1), and superior cycle stability (500 cycles). Note that the surface conversion reactions play a dominant role in the electrochemical process of KFF-CNTs, together with the stable octahedral perovskite structure and nanoscale particle sizes achieving high ion diffusion coefficients. Furthermore, the specific lithium storage mechanism of KFF has been explored by the distribution of relaxation times technology. This work opens up a new way for developing cubic perovskite fluorides as high-capacity and robust anode materials for LIBs.

Spatial distribution patterns across multiple microbial taxonomic groups.

Even in the vertical dimension, soil bacterial communities are spatially distributed in a distance-decay relationship (DDR). However, whether this pattern is universal among all soil microbial taxonomic groups, and how body size influences this distribution, remains elusive. Our study consisted of obtaining 140 soil samples from two adjacent ecosystems in the Yellow River Delta (YRD), both nontidal and tidal, and measuring the DDR between topsoil and subsoil for bacteria, archaea, fungi and protists (rhizaria). Our results showed that the entire community generally fitted the DDR patterns (P < 0.001), this was also true at the kingdom level (P < 0.001, with the exception of the fungal community), and for most individual phyla (47/75) in both ecosystems and with soil depth. Meanwhile, these results presented a general trend that the community turnover rate of nontidal soils was higher than tidal soils (P < 0.05), and that the rate of topsoil was also higher than that of subsoil (P < 0.05). Additionally, microbial spatial turnover rates displayed a negative relationship with body sizes in nontidal topsoil (R2 = 0.29, P = 0.009), suggesting that the smaller the body size of microorganisms, the stronger the spatial limitation was in this environment. However, in tidal soils, the body size effect was negligible, probably owing to the water's fluidity. Moreover, community assembly was judged to be deterministic, and heterogeneous selection played a dominant role in the different environments. Specifically, the spatial distance was much more influential, while the soil salinity in these ecosystems was the major environmental factor in selecting the distributions of microbial communities. Overall, this study revealed that microbial community compositions at different taxonomic levels followed relatively consistent distribution patterns and mechanisms in this coastal area.

Nitrogen/Oxygen Co-Doped Hierarchically Porous Carbon for High-Performance Potassium Storage.

Although the insertion of potassium ions into graphite has been proven to be realistic, the electrochemical performance of potassium-ion batteries (PIBs) is not yet satisfactory. Therefore, more effort is required to improve the specific capabilities and achieve a long cycling life. The mild carbonization process in molten salt (NaCl-KCl) is used to synthesize nitrogen/oxygen co-doped hierarchically porous carbon (NOPC) for PIBs by using cyanobacteria as the carbon source. This exhibits highly reversible capacities and ultra-long cycling stability, retaining a capacity of 266 mA h g-1 at 50 mA g-1 (100 cycles) and presents a capacity of 104.3 mA h g-1 at 1000 mA g-1 (1000 cycles). Kinetics analysis reveals that the potassium ion (K+ ) storage of NOPC is controlled by a capacitive process, which plays a crucial role in the excellent rate performance and superior reversible ability. The high proportion of capacitive behavior can be ascribed to the hierarchically porous structure and improved conductivity resulting from nitrogen and oxygen doping. Furthermore, density functional theory (DFT) calculations theoretically validate the enhanced potassium storage effect of the as-obtained NOPC. More importantly, the route to NOPC from cyanobacteria in molten salt provides a green approach to the synthesis of porous carbon materials.

Porous CoC2O4/Graphene Oxide Nanocomposite for Advanced Potassium-Ion Storage.

Potassium-ion batteries (PIBs), as one of the alternatives to lithium-ion batteries (LIBs), have attracted considerable attention on account of the affluence and low-cost of potassium. Moreover, CoC2O4 and graphene oxide (GO) have been used very well in lithium-ion batteries. Hence, the hybrid CoC2O4/GO was investigated as a new anode material for PIBs. The hybrid CoC2O4/GO was synthesized by a facile and cheap method combined with supersonic dispersion. Electrochemical measurements reveal that the hybrid CoC2O4/GO delivered an excellent cycling stability of 166 mAh g-1 at 50 mA g-1 and a superior rate capability even at 1 A g-1. These results demonstrate although the cycle ability was insufficient for practical applications, transition-metal oxalates composites can still bring new hope to the development of PIBs.

Phosphorus Particles Embedded in Reduced Graphene Oxide Matrix to Enhance Capacity and Rate Capability for Capacitive Potassium-Ion Storage.

Early studies indicate that graphite is feasible as the negative electrode of a potassium-ion battery, but its electrochemical performance still cannot meet the demands of applications. More efforts should be focused on increasing the specific capacity and improving the rate capability in the meantime. Thus, stainless-steel autoclave technology has been utilized to prepare phosphorus nanoparticles encapsulated in reduced graphene oxide matrix as the electrode materials for a potassium-ion battery. As a result, the composite matrix affords high reversible capacities of 354 and 253 mA h g-1 at 100 and 500 mA g-1 , respectively. The superior electrochemical performance is mainly because the composite matrix possesses better electronic conductivity and a robust structure, which can promote the electron-transfer performance of the electrode. Furthermore, phosphorus particles can contribute to the high capacity through an alloying mechanism. In addition, the silklike, ultrathin, film composite with a high surface area is conducive to capacitive potassium-ion storage, which plays a more important role in rate performance and a high current density capability.

One-Pot Hydrothermal Synthesis of FeMoO4 Nanocubes as an Anode Material for Lithium-Ion Batteries with Excellent Electrochemical Performance.

Metal molybdates nanostructures hold great promise as high-performance electrode materials for next-generation lithium-ion batteries. In this work, the facial design and synthesis of monodisperse FeMoO4 nanocubes with the edge lengths of about 100 nm have been successfully prepared and present as a novel anode material for highly efficient and reversible lithium storage. Well-defined single-crystalline FeMoO4 with high uniformity are first obtained as nanosheets and then self-aggregated into nanocubes. The morphology of the product is largely controlled by the experimental parameters, such as the reaction temperature and time, the ratio of reactant, the solution viscosity, etc. The molybdate nanostructure would effectively promote the insertion of lithium ions and withstand volume variation upon prolonged charge/discharge cycling. As a result, the FeMoO4 nanocubes exhibit high reversible capacities of 926 mAh g(-1) after 80 cycles at a current density of 100 mA g(-1) and remarkable rate performance, which indicate that the FeMoO4 nanocubes are promising materials for high-power lithium-ion battery applications.

One-step solid state reaction to synthesis of hexagonal BN crystals with rod-like morphology.

Hexagonal BN crystals have been synthesized from a facile one-step solid state reaction route by sodium tetraphenylborate, hydrazine, zinc powder and sulphur powder as the reactants. The SEM and TEM results showed the BN crystals had the morphology of one-dimensional rod-like shape and with diameters in the range of 100-200 nm and lengths up to several micrometers. Compared with the other reported methods, this route has greatly reduced the reaction temperature. In addition, the growth mechanism of the BN nanorods was discussed in detail. Meanwhile, thermal gravimetric analysis results indicated that the as-prepared BN nanorods have the excellent thermal stability and anti-oxidation properties.

Durable Ru Nanocrystal with HfO2 Modification for Acidic Overall Water Splitting.

Durable and efficient bi-functional catalyst, that is capable of both oxygen evolution reaction and hydrogen evolution reaction under acidic condition, are highly desired for the commercialization of proton exchange membrane water electrolysis. Herein, we report a robust L-Ru/HfO2 heterostructure constructed via confining crystalline Ru nanodomains by HfO2 matrix. When assembled with a proton exchange membrane, the bi-functional L-Ru/HfO2 catalyst-based electrolyzer presents a voltage of 1.57 and 1.67 V to reach 100 and 300 mA cm-2 current density, prevailing most of previously reported Ru-based materials as well as commercial Pt/C||RuO2 electrolyzer. It is revealed that the synergistic effect of HfO2 modification and small crystalline domain formation significantly alleviates the over-oxidation of Ru. More importantly, this synergistic effect facilitates a dual-site oxide path during the oxygen evolution procedure via optimization of the binding configurations of oxygenated adsorbates. As a result, the Ru active sites maintain the metallic state along with reduced energy barrier for the rate-determining step (*O→*OOH). Both of water adsorption and dissociation (Volmer step) are strengthened, while a moderate hydrogen binding is achieved to accelerate the hydrogen desorption procedure (Tafel step). Consequently, the activity and stability of acidic overall water splitting are simultaneously enhanced.

The Microbiome Protocols eBook initiative: Building a bridge to microbiome research.

The Microbiome Protocols eBook (MPB) serves as a crucial bridge, filling gaps in microbiome protocols for both wet experiments and data analysis. The first edition, launched in 2020, featured 152 meticulously curated protocols, garnering widespread acclaim. We now extend a sincere invitation to researchers to participate in the upcoming 2nd version of MPB, contributing their valuable protocols to advance microbiome research.

Iodine assisted low temperature synthesis of 3C-SiC nanostructures and their formation process.

3C-SiC nanostructures have been synthesized from Si, maltose or glucose and Mg at 120 degrees C in the presence of I2. The as-obtained products are the mixtures of wire-like and tower-shaped SiC nanostructures. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) images show that wire-like nanostructures are formed by the leaning-type packing of triangular nanosheets with the average diameter of 60 nm and tower-shaped nanostructures are formed by the level-type packing of nanosheets with the average diameter of 750 nm and thickness of about 40 nm. The effects of iodine, reaction time and temperature on the morphologies of the final products were also discussed.

Ether-based electrolytes enable the application of nitrogen and sulfur co-doped 3D graphene frameworks as anodes in high-performance sodium-ion batteries.

The development of graphitic carbon materials as anodes of sodium-ion batteries (SIBs) is greatly restricted by their inherent low specific capacity. Herein, nitrogen and sulfur co-doped 3D graphene frameworks (NSGFs) were successfully synthesized via a simple and facile one-step hydrothermal method and exhibited high Na storage capacity in ether-based electrolytes. A systematic comparison was made between NSGFs, undoped graphene frameworks (GFs) and nitrogen-doped graphene frameworks (NGFs). It is demonstrated that the high specific capacity of NSGFs can be attributed to the free diffusion of Na ions within the graphene layer and reversible reaction between -C-Sx-C- covalent chains and Na ions thanks to the large interplanar distance and the dominant -C-Sx-C- covalent chains in NSGFs. NSGF anodes, therefore, exhibit a high initial coulombic efficiency (ICE) (92.8%) and a remarkable specific capacity of 834.0 mA h g-1 at 0.1 A g-1. Kinetic analysis verified that the synergetic effect of N/S co-doping not only largely enhanced the Na ion diffusion rate but also reduced the electrochemical impedance of NSGFs. Postmortem techniques, such as SEM, ex situ XPS, HTEM and ex situ Raman spectroscopy, all demonstrated the extremely physicochemically stable structure of the 3D graphene matrix and ultrathin inorganic-rich solid electrolyte interphase (SEI) films formed on the surface of NSGFs. Yet it is worth noting that the Na storage performance and mechanism are exclusive to ether-based electrolytes and would be inhibited in their carbonate ester-based counterparts. In addition, the corrosion of copper foils under the synergetic effect of S atoms and ether-based electrolytes was reported for the first time. Interestingly, by-products derived from this corrosion could provide additional Na storage capacity. This work sheds light on the mechanism of improving the electrochemical performance of carbon-based anodes by heteroatom doping in SIBs and provides a new insight for designing high-performance anodes of SIBs.

Early inoculation of an endophyte alters the assembly of bacterial communities across rice plant growth stages.

The core endophytes of plants are regarded as promising resources in future agroecosystems. How they affect the assembly of rice-related bacterial communities after early inoculation remains unclear. Here, we examined bacterial communities across 148 samples, including bulk and rhizosphere soils, sterilized roots, stems, and seeds at the seedling, tillering, booting, and maturity stages. Tissue cultured rice seedlings were inoculated with Xathomonas sacchari JR3-14, a core endophytic bacterium of rice seeds, before transplanting. The results revealed that α-diversity indices were significantly enhanced in the root and stem endosphere at the seedling stage. ß-diversity was altered at most plant developmental stages, except for the root and stem at the booting stage. Network complexity consequently increased in the root and stem across rice growth stages, other than the stem endosphere at the booting stage. Four abundant beneficial bacterial taxa, Bacillus, Azospira, Azospirillum, and Arthrobacter, were co-enriched during the early growth stage. Infer Community Assembly Mechanisms by Phylogenetic-bin-based null model analysis revealed a higher relative contribution of drift and other eco-evolutionary processes mainly in root compartments across all growth stages, but the opposite pattern was observed in stem compartments. IMPORTANCE Endophytic bacteria are regarded as promising environmentally friendly resources to promote plant growth and plant health. Some of microbes from the seed are able to be carried over to next generation, and contribute to the plant's ability to adapt to new environments. However, the effects of early inoculation with core microbes on the assembly of the plant microbiome are still unclear. In our study, we demonstrate that early inoculation of the rice seed core endophytic bacterium Xanthomonas sacchari could alter community diversity, enhance complexity degree of network structure at most the growth stages, and enrich beneficial bacteria at the seedling stage of rice. We further analyzed the evolutionary processes caused by the early inoculation. Our results highlight the new possibilities for research and application of sustainable agriculture by considering the contribution of seed endophytes in crop production and breeding.

Biochemical fulvic acid derived amorphous carbon modified microcrystalline graphite as low-cost anode for potassium-ion storage.

Graphite anode has great potential toward potassium ion storage for abundant reserves, yet it suffers from the large volume expansion and slow diffusion rate. Herein, the low-cost biochemical fulvic acid-derived amorphous carbon (BFAC) is employed to modify the natural microcrystalline graphite (BFAC@MG) by a simple mixed carbonization strategy. The BFAC smooths the split layer and folds on the surface of microcrystalline graphite and builds the heteroatom-doped composite structure, which effectively alleviates the volume expansion caused by K+ electrochemical de-intercalation processes, together with improving electrochemical reaction kinetics. As expected, the optimized BFAC@MG-0.5 exhibits superior potassium-ion storage performance, which delivers a high reversible capacity (623.8 mAh g-1), excellent rate performance (147.8 mAh g-1 at 2 A g-1), and remarkable cycling stability (100.8 mAh g-1 after 1200 cycles). As a practical device application, the potassium-ion capacitors are assembled using the BFAC@MG-0.5 anode and commercial activated carbon cathode, which exhibits a maximum energy density of 126.48 Wh kg-1 and superior cycle stability. Significantly, this work demonstrates the potential of microcrystalline graphite as the host anode material for potassium-ion storage.

EasyAmplicon: An easy-to-use, open-source, reproducible, and community-based pipeline for amplicon data analysis in microbiome research.

It is difficult for beginners to learn and use amplicon analysis software because there are so many software tools to choose from, and all of them need multiple steps of operation. Herein, we provide a cross-platform, open-source, and community-supported analysis pipeline EasyAmplicon. EasyAmplicon has most of the modules needed for an amplicon analysis, including data quality control, merging of paired-end reads, dereplication, clustering or denoising, chimera detection, generation of feature tables, taxonomic diversity analysis, compositional analysis, biomarker discovery, and publication-quality visualization. EasyAmplicon includes more than 30 cross-platform modules and R packages commonly used in the field. All steps of the pipeline are integrated into RStudio, which reduces learning costs, keeps the flexibility of the analysis process, and facilitates personalized analysis. The pipeline is maintained and updated by the authors and editors of WeChat official account "Meta-genome." Our team will regularly release the latest tutorials both in Chinese and English, read the feedback from users, and provide help to them in the WeChat account and GitHub. The pipeline can be deployed on various platforms, and the installation time is less than half an hour. On an ordinary laptop, the whole analysis process for dozens of samples can be completed within 3 h. The pipeline is available at GitHub (https://github.com/YongxinLiu/EasyAmplicon) and Gitee (https://gitee.com/YongxinLiu/EasyAmplicon).

Branched mesoporous Mn3O4 nanorods: facile synthesis and catalysis in the degradation of methylene blue.

Branched MnOOH nanorods with diameters in the range of 50-150 nm and lengths of up to tens of micrometers were prepared by using potassium permanganate (KMnO(4)) and PEG 400 (PEG=polyethylene glycol) as starting materials through a simple hydrothermal process at 160 °C. After annealing at 300 °C under a N(2) atmosphere for 5 h, MnOOH nanorods became gradually dehydrated and transformed into mesoporous Mn(3)O(4) nanorods with a slight size-shrinking. The as-obtained mesoporous Mn(3)O(4) nanorods had an average surface area of 32.88 m(2) g(-1) and a mean pore size of 3.7 nm. Through tuning the experimental parameters, such as the annealing atmosphere and temperature, ß-MnO(2), Mn(2)O(3), Mn(3)O(4), MnO, and Mn(5)O(8) were selectively produced. Among these structures, mesoporous Mn(3)O(4) nanorods were efficient for the catalytic degradation of methylene blue (MB) in the presence of H(2)O(2) at 80 °C.

MnCO3 microstructures assembled with nanoparticles: shape-controlled synthesis and their application for Li-ion batteries.

MnCO3 ellipsoids and twinborn spheres have been synthesized by a hydrothermal process and a room temperature synthesis approach, respectively. The structures and morphologies of the products are investigated by X-ray powder diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). XRD patterns indicate the MnCO3 ellipsoids display higher crystallinity than twinborn spheres. SEM images show that both the MnCO3 ellipsoids and twinborn spheres have a similar size of about 1 microm and consist of nanoscale primary particles. Brunauer-Emmett-Teller (BET) surface areas of MnCO3 ellipsoids and twinborn spheres are 33.93 and 59.35 m2/g, respectively. Furthermore, the lithium storage properties of these MnCO3 samples with distinct morphologies have been investigated. When used as anode materials in lithium-ion batteries, MnCO3 ellipsoids and twinborn spheres exhibit the initial discharge capacities of 1375 and 1650 mAh/g, respectively. After charged/discharged for 50 cycles at a current density of 500 mA/g, the remaining discharge capacities for MnCO3 ellipsoids and twinborn spheres are 663 and 305 mAh/g, respectively.