Synergistic regulation at physiological, transcriptional and metabolic levels in tomato plants subjected to a combination of salt and heat stress.

With global warming and climate change, abiotic stresses often simultaneously occur. Combined salt and heat stress was a common phenomenon that was severe, particularly in arid/semi-arid lands. We aimed to reveal the systematic responsive mechanisms of tomato genotypes with different salt/heat susceptibilities to combined salt and heat stress. Morphological and physiological responses of salt-tolerant/sensitive and heat-tolerant/sensitive tomatoes at control, heat, salt and combined stress were investigated. Based on leaf Fv /Fm and H2 O2 content, samples from tolerant genotype at the four treatments for 36 h were taken for transcriptomics and metabolomics. We found that plant height, dry weight and net photosynthetic rate decreased while leaf Na+ concentration increased in all four genotypes under salt and combined stress than control. Changes in physiological indicators such as photosynthetic parameters and defence enzyme activities in tomato under combined stress were regulated by the expression of relevant genes and the accumulation of key metabolites. We screened five key pathways in tomato responding to a combination of salt and heat stress, such as oxidative phosphorylation (map00190). Synergistic regulation at morphological, physiological, transcriptional and metabolic levels in tomato plants was induced by combined stress. Heat stress was considered as a dominant stressor for tomato plants under the current combined stress. The oxidative phosphorylation pathway played a key role in tomato in response to combined stress, where tapped key genes (e.g. alternative oxidase, Aox1a) need further functional analysis. Our study will provide a valuable resource important for studying stress combination and improving tomato tolerance.

ROS-mediated waterlogging memory, induced by priming, mitigates photosynthesis inhibition in tomato under waterlogging stress.

With global climate change, the frequency and intensity of waterlogging events are increasing due to frequent and heavy precipitation. Little is known however about the response of plants to repeated waterlogging stress events. The aim is to clarify physiological regulation mechanisms of tomato plants under repeated waterlogging stress, and whether Trichoderma harzianum can alleviate waterlogging injury. We identified two genotypes of tomato, 'MIX-002' and 'LA4440', as waterlogging tolerant and sensitive genotypes, respectively, based on plant biomass accumulation. The two tomato genotypes were subjected to a waterlogging priming treatment for 2 days (excess water for 1 cm above substrate surface) followed by a recovery stage for 2 days, and then a second waterlogging stress for 5 days (excess water for 1 cm above substrate surface) followed by a second recovery stage for 3 days. Leaf physiological, plant growth parameters, and the expression of five key genes were investigated. We found that the two genotypes responded differently to waterlogging priming and stress in terms of photosynthesis, reactive oxygen species (ROS), and osmotic regulatory mechanisms. Waterlogging stress significantly increased H2O2 content of 'MIX-002', while that of 'LA4440' had no significant change. Under waterlogging stress, photosynthesis of the two genotypes treated with waterlogging priming returned to the control level. However, Trichoderma harzianum treatment during the second recovery stage did not show positive mitigative effects. The plants of 'LA4440' with priming showed lower peroxidase (POD) activity and proline content but higher H2O2 content than that without priming under waterlogging stress. Under waterlogging stress with priming as compared to without priming, SODCC2 was downregulated in two tomatoes, and AGR2 and X92888 were upregulated in 'MIX-002' but downregulated in 'LA4440'. Overall, the two tomato genotypes exhibited distinct photosynthetic, ROS and osmotic regulatory mechanisms responding to the waterlogging stress. Waterlogging priming can induce stress memory by adjusting stomatal conductance, sustaining ROS homeostasis, regulating osmotic regulatory substances and key gene expressions mediated by H2O2, and thus alleviate the damage on tomato photosynthesis when waterlogging reoccurred.

First report of Diaporthe sojae causing stem canker on blueberry in China.

Blueberry (Vaccinium corymbosum) plants are popular all over the world due to their high nutritional value and health benefits. In October 2020, blueberry stems (cv. O'Neal) displaying reddish brown necrotic lesions were observed from a blueberry field in Anqing (Anhui, China), with the incidence of approximately 90%. The affected plants were somewhat stunted that had smaller fruit, and in severe cases, partial or whole plant died. We randomly selected three sampling sites to collect stems with the symptoms. Samples at the margin between diseased and healthy tissues were taken out, cut into 5 mm pieces in length，and then mixed them together. Twenty small samples were surface-sterilized, and plated onto potato dextrose agar (PDA). The plates were incubated at 25°C in the dark until fungal colonies were observed. After subculturing single hyphal tips, 9 out of 12 fungal isolates with similar morphologies were obtained. The representative isolate, LMKY12 was selected for further identification. The colonies on PDA showed white, fluffy aerial mycelia with 7.9  0.2 mm (n=5) diameter after inoculation in darkness at 25°C for one week. The colony darkens in color with age, yellowish pigmentation in reverse were observed. After 15 days of incubation, dark brown, irregular hard particles (fruiting bodies in sexual stage) accumulated on the surface of the colonies. Asci were 8-spored, sessile, club-like, hyaline, and 35-46 x 6-9 µm (n=30) in size. The ascospores were oval or spindle shaped, two-celled, constricted at division, and containing four guttulates with larger guttules at centre and smaller one at ends, measured 9-11 x 2-4 um (n=50). No sporulation observed on blueberry stems after inoculated 30 days. In order to induce the production of conidiophores, mycelial plugs were placed on blueberry leaves and cultured in darkness at 25°C. There are two types of conidia observed after 20 days of inoculation. Alpha conidia were aseptate, hyaline, smooth, ovate to ellipsoidal, often biguttulate, measured 5.33-7.26 x 1.65-2.53 µm (n=50). Beta conidia were hyaline, linear, measured 12.60-17.91 x 0.81-1.38 µm (n=30). The morphological characteristics matched the previous description of D. sojae (Udayanga et al. 2015; Guo et al. 2020). To confirm the identification, the mycelial genomic DNA of LMKY12 was extracted as a template. The rDNA internal transcribed spacer (ITS), translation elongation factor 1-α gene (TEF1-α), and calmodulin (CAL) were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R, and CAL-228F/CAL-737R (Carbone and Kohn 1999), respectively. BLAST analysis revealed that the ITS (ON545758), CAL (OP886852), and TEF1-α (OP886853) sequences were 100% (527/527 base pairs), 99.21% (504/508 base pairs), and 99.41% (336/338 base pairs) similar to the strain FAU636 of D. sojae (KJ590718, KJ612115, KJ590761), respectively. Phylogenetic analysis based on concatenated sequences of ITS, TEF1-α, and CAL using MEGA 7.0 by maximum likelihood attributed the isolate LMKY12 to the D. sojae clade. Pathogenicity tests were performed on blueberry cv. O'Neal using detached stems (n=8) in laboratory, one-year-old potted plants (n=4) in greenhouse. Inoculations were done by placing mycelial plugs (7 mm in diameter) taken from a 7-day-old PDA culture on wounded stems. Inoculations with uncolonized agar plugs served as negative controls. Reddish dark brown lesions similar to the symptoms were observed on all inoculated stems 7 days after inoculation. No symptoms developed on control stems. Reisolations were successfully made from all the inoculated stems, and the pathogen was confirmed by the presence of pycnidia, alpha conidia and beta conidia. To our knowledge, this is the first report of D. sojae causing blueberry stem canker in China.

Effect of a co-fermentation system with high-GABA-yielding strains on soymilk properties: microbiological, physicochemical, and aromatic characterisations.

Biosynthesis is the safest method for preparing GABA; however, there are not enough GABA-producing strains to provide an effective resource. The purpose of this study was to determine the feasibility of using Lactobacillus fermentum SMN10-3(A) and Lactococcus lactis SMN15-6(B) to study the effects of strain complex pairing on the GABA formation, flavour, and metabolic pathways of fermented soymilk. It was found that group A2B1 had the highest acid production rate, GABA yield (1.76 ± 0.01 mg/mL), and flavour compound content. A total of 55 differential metabolites were produced after fermentation, of which 28 dominated by hexanal were significantly downregulated and 26 dominated by alcohols were significantly upregulated. The significant metabolic pathways involved were d-alanine, taurine and hypotaurine, and selenocompound metabolism. Finally, the components contributing to the aroma of fermented soymilk were identified, which included 2-pentylfuran and 2-butyl-2-octenal. These results provide a theoretical basis for future research on GABA-rich fermented foods.

Impact of granular inclusions on the phase behavior of colloidal gels.

Colloidal gels formed from small attractive particles are commonly used in formulations to keep larger components in suspension. Despite extensive work characterising unfilled gels, little is known about how the larger inclusions alter the phase behavior and microstructure of the colloidal system. Here we use numerical simulations to examine how larger 'granular' particles can alter the gel transition phase boundaries. We find two distinct regimes depending on both the filler size and native gel structure: a 'passive' regime where the filler fits into already-present voids, giving little change in the transition, and an 'active' regime where the filler no longer fits in these voids and instead perturbs the native structure. In this second regime the phase boundary is controlled by an effective colloidal volume fraction given by the available free volume.

Variation and Correlation Analysis of Flavour and Bacterial Diversity of Low-Salt Hotpot Sauce during Storage.

Culinary circles have experienced a recent trend towards low-salt hotpot sauces. Here, changes in the physicochemical quality, flavour, and bacterial diversity of hotpot sauces with different salt concentrations were studied during storage. The results indicated that the peroxide and acid values of hotpot sauce increased gradually and that the quality began to deteriorate with storage. A storage temperature of 4 °C and salt concentration above 4.4% significantly reduced spoilage. The salt concentration had no significant effect on the flavour but extended storage resulted in significant differences in flavour reflected in the changes of sweet, sour, bitter, umami, aftertaste-A, abundance, organic sulphide, and alkanes. Significant differences were found in the bacterial composition between samples stored at different temperatures. Norank-f-o-Chloroplast was the main bacterium in the samples stored at low temperatures, which was beneficial for preservation. Bacillus was detected in 4.1% NaCl samples stored at 25 °C, directly promoting sauce spoilage and an unpleasant flavour. This bacterium signalled the spoilage of low-salt hotpot sauce stored at room temperature.

Phylogeny and functional characterization of the cinnamyl alcohol dehydrogenase gene family in Phryma leptostachya.

Phryma leptostachya has attracted increasing attention because it is rich in furofuran lignans with a wide range of biological activities. Biosynthesis of furofuran lignans begins with the dimerization of coniferyl alcohol, one of the monolignol. Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step of monolignol biosynthesis, reducing cinnamyl aldehydes to cinnamyl alcohol. As it is in the terminal position of monolignol biosynthesis, its type and activity can cause significant changes in the total amount and composition of lignans. Herein, combined with bioinformatics analysis and in vitro enzyme assays, we clarified that CAD in P. leptostachya belonged to a multigene family, and identified nearly the entire CAD gene family. Our in-depth characterization about the functions and structures of two major CAD isoforms, PlCAD2 and PlCAD3, showed that PlCAD2 exhibited the highest catalytic activity, and coniferyl aldehyde was its preferred substrate, followed by PlCAD3, and sinapyl aldehyde was its preferred substrate. Considering the accumulation patterns of furofuran lignans and expression patterns of PlCADs, we speculated that PlCAD2 was the predominant CAD isoform responsible for furofuran lignans biosynthesis in P. leptostachya. Moreover, these CADs found here can also provide effective biological parts for lignans and lignins biosynthesis.

Multi-model train state estimation based on multi-sensor parallel fusion filtering.

Accurately determining a train's state is essential for passenger safety, operation efficiency, and maintenance. However, the actual operation state of a train is composed of a variety of modes and is disturbed by several known or unknown factors, for which an accurate estimator is required. Hence, in this paper, a train multi-mode model considering the actual operation environment is established, and a train state estimation method based on multi-sensor parallel fusion filter is proposed. In the parallel fusion filter, the current mode of train is determined by the proposed sliding window error and voting mechanism, and the global filter are constituted by the local filters, which are fused by linear-weighted summation. The simulation results demonstrate the effectiveness of our method in estimating the train's state. It is worth noting that even if monitoring data are missing or are abnormal, the state estimation accuracy of the proposed technique still meets the requirements of a real system, and the effectiveness and robustness of the method can be verified.

All-dielectric thin films based on single silicon materials for angle-insensitive structural colors.

Here we demonstrate a red structural color of a multilayer structure made of all silicon-based materials. By using amorphous silicon (a-Si) and silicon dioxide (SiO2) with a large difference in the refractive index, high reflection efficiency can be achieved with only a few layers. The anti-reflection unit composed of top silicon monoxide (SiO) and SiO2 layers can significantly reduce the reflection intensity of the non-target wavelengths to ensure that the device has good color saturation. The selective absorption of SiO and a-Si layers can further improve the color saturation. By reasonably controlling the thickness of the highly absorbing materials, the device has good angular insensitivity at an incident angle of 0°-60°. Furthermore, the angle-insensitive blue and yellow structural colors are also realized based on the all silicon design idea. This scheme is simple in structure and capable of efficient mass production. This method has enormous potential for diverse applications in display, colorful decoration, anti-counterfeiting, and so forth.

Fault Diagnosis of Brake Train Based on Multi-Sensor Data Fusion.

In this paper, a fault diagnosis method is proposed based on multi-sensor fusion information for a single fault and composite fault of train braking systems. Firstly, the single mass model of the train brake is established based on operating environment. Then, the pre-allocation and linear-weighted summation criterion are proposed to fuse the monitoring data. Finally, based on the improved expectation maximization, the braking modes and braking parameters are identified, and the braking faults are diagnosed in real time. The simulation results show that the braking parameters of systems can be effectively identified, and the braking faults can be diagnosed accurately based on the identification results. Even if the monitoring data are missing or abnormal, compared with the maximum fusion, the accuracies of parameter identifications and fault diagnoses can still meet the needs of the actual systems, and the effectiveness and robustness of the method can be verified.

Transcriptome analysis of Plantago major as a phytoremediator to identify some genes related to cypermethrin detoxification.

Cypermethrin (CYP) is a toxic manmade chemical compound belonging to pyrethroid insecticides contaminating the environment. Plantago major (PM) has numerous excellent advantages like high biomass yield and great stress tolerance, which make it able to increase the efficacy of phytoremediation. So far, no study has directly or indirectly made a transcriptome analysis (RNA-seq) of PM under CYP stress. The aim of this study is to identify the genes in PM related to CYP detoxification (10 µg mL-1) and compared with control. In this study, BGISEQ-500 high-throughput sequencing technology independently developed by BGI was used to sequence the transcriptome of P. major. Six libraries were constructed including (CK_1, CK_2, and CK_3) and (CYP_1, CYP_2, and CYP_3) were sequenced for transcripts involved in CYP detoxification. Our data showed that de novo assembly generated 138,806 unigenes with an average length of 1129 bp. Analyzing the annotation results of the KEGG database between the samples revealed 37,177 differentially expressed genes (DEGs), 18,062 down- and 19,115 upregulated under CYP treatment compared with control. A set of 107 genes of cytochrome P450 (Cyt P450), 43 genes of glutathione S-transferases (GST), 25 genes of glycosyltransferases (GTs), 113 genes from ABC transporters, 21 genes from multidrug and toxin efflux (MATE), 11 genes from oligopeptide transporter (OPT), and 3 genes of metallothioneins (MT) were upregulated notably. By using quantitative real-time PCR (qRT-PCR), the results of gene expression for 12 randomly selected DEGs were confirmed, showing the different patterns of response to CYP in PM tissues. Furthermore, the enzyme activity of Cyt P450 and GST in PM under CYP stress was significantly increased in roots and leaves than in control. This study introduces a clue to understand the metabolic pathways of plants used in phytoremediation by identifying the highly expressed genes related to phytoremediation which would be utilized to enhance pesticide detoxification and reduce pollution problem.

Determination of Dynamic Interfacial Tension during the Generation of Tiny Droplets in the Liquid-Liquid Jetting Flow Regime.

Liquid-liquid dispersion coupled with droplet formation and mass transfer of surfactants is one of the most typical phenomena in many chemical processes. As in every aspect of this process, the interfacial tension variation caused by the unsaturated adsorption of surfactants on the droplet surface plays an important role. This article focuses on microdroplet formation and the dynamic interfacial behavior of surfactants in the jetting regime. In a capillary embedded step T-junction device, controllable preparation of monodisperse droplets is achieved, and a correlation for predicting droplet sizes is established. A method for measuring the dynamic interfacial tension is provided. Mass transfer coefficients are then calculated for Tween 20 during the droplet formation process by a semiempirical correlation. The results indicate that dynamic interfacial tensions are lower than those obtained when the surfactant is adsorbed to equilibrium. Based on the tip-streaming phenomenon, mass transfer coefficients for Tween 20 can reach up to ∼10-3 m/s, higher than those obtained in coaxial microfluidic devices. All the preliminary results shed light on the nature of droplet formation and will be of significance for application in industrial apparatuses.

An electrochemical sensor for ifosfamide, acetaminophen, domperidone, and sumatriptan based on self-assembled MXene/MWCNT/chitosan nanocomposite thin film.

New multi-walled carbon nanotubes supported on Ti3C2-MXene and chitosan (chit) composite film-based electrochemical sensor for ifosfamide (IFO), acetaminophen (ACOP), domperidone (DOM), and sumatriptan (SUM) have been developed. Ti3C2-MXene was synthesized by a fluoride method. Structural and chemical characterizations suggested the successful preparation of Ti3C2-MXene with clearly seen layered morphology, defined 0 0 2 diffraction peak at 7.5° and complete absence of 1 0 4 plane at 39°. The electrochemical performance of the sensor was investigated by cyclic voltammetry and adsorptive stripping differential pulse voltammetry. The Ti3C2/MWCNT/Chit modified glassy carbon electrode exhibits enhanced electrocatalytic activities toward the oxidation of target analytes. Excellent conductivity, large surface area, and high catalytic properties of the Ti3C2-MXene showed synergistic effects with MWCNTs and helped in achieving low detection limits of targets with high selectivity and reproducibility. The assay allows determination of IFO, ACOP, DOM, and SUM in the concentration ranges 0.0011-1.0, 0.0042-7.1, 0.0046-7.3, and 0.0033-61 µM with low detection limits of 0.00031, 0.00028, 0.00034, and 0.00042 µM, respectively. The sensor was successfully applied for voltammetric screening of target analytes in urine and blood serum samples with recoveries > 95.21%. Schematic illustration of the synthesis of self-assembled MXene/MWCNT/chitosan nanocomposite is given and its application to the voltammetric determination of ifosfamide, acetaminophen, domperidone, and sumatriptan described. Graphical abstract.

An unexpected N-dependence in the viscosity reduction in all-polymer nanocomposite.

Adding small nanoparticles (NPs) into polymer melt can lead to a non-Einstein-like decrease in viscosity. However, the underlying mechanism remains a long-standing unsolved puzzle. Here, for an all-polymer nanocomposite formed by linear polystyrene (PS) chains and PS single-chain nanoparticles (SCNPs), we perform large-scale molecular dynamics simulations and experimental rheology measurements. We show that with a fixed (small) loading of the SCNP, viscosity reduction (VR) effect can be largely amplified with an increase in matrix chain length [Formula: see text], and that the system with longer polymer chains will have a larger VR. We demonstrate that such [Formula: see text]-dependent VR can be attributed to the friction reduction experienced by polymer segment blobs which have similar size and interact directly with these SCNPs. A theoretical model is proposed based on the tube model. We demonstrate that it can well describe the friction reduction experienced by melt polymers and the VR effect in these composite systems.

NanoPOP: Solution-Processable Fluorescent Porous Organic Polymer for Highly Sensitive, Selective, and Fast Naked Eye Detection of Mercury.

Fluorescence-based detection is one of the most efficient and cost-effective methods for detecting hazardous, aqueous Hg2+. We designed a fluorescent porous organic polymer (TPA-POP-TSC), with a "fluorophore" backbone and a thiosemicarbazide "receptor" for Hg2+-targeted sensing. Nanometer-sized TPA-POP-TSC spheres (nanoPOP) were synthesized under mini-emulsion conditions and showed excellent solution processability and dispersity in aqueous solution. The nanoPOP sensor exhibits exceptional sensitivity (Ksv = 1.01 × 106 M-1) and outstanding selectivity for Hg2+ over other ions with rapid response and full recyclability. Furthermore, the nanoPOP material can be easily coated onto a paper substrate to afford naked eye-based Hg2+-detecting test strips that are convenient, inexpensive, fast, highly sensitive, and reusable. Our design takes advantage of the efficient and selective capture of Hg2+ by thiosemicarbazides (binding energy = -29.84 kJ mol-1), which facilitates electron transfer from fluorophore to bound receptor, quenching the sensor's fluorescence.

Insecticidal Activity of Four Lignans Isolated from Phryma leptostachya.

A new lignan (T4) and three known lignans (T1, T2, and T3) were isolated from the methanol extract of the roots of Phryma leptostachya using bioassay-guided method, and their structures were identified as phrymarolin I (T1), II (T2), haedoxan A (T3), and methyl 4-((6a-acetoxy-4-(6-methoxybenzo[d][1,3]dioxol-5-yl)tetrahydro-1H,3H-furo[3,4-c]furan-1-yl)oxy)-1-hydroxy-2,2-dimethoxy-5-oxocyclopent-3-ene-1-carboxylate (T4) byNMR and ESI-MS spectral data. Bioassay results revealed that haedoxan A exhibited remarkably high insecticidal activity against Mythimna separata with a stomach toxicity LC50 value of 17.06 mg/L and a topical toxicity LC50 value of 1123.14 mg/L at 24 h, respectively. Phrymarolin I and compound T4 also showed some stomach toxicity against M. separata with KD50 values of 3450.21 mg/L at 4 h and 2807.10 mg/L at 8 h, respectively. In addition, phrymarolin I and haedoxan A exhibited some stomach toxicity against Plutella xylostella with an LC50 value of 1432.05 and 857.28 mg/L at 48 h, respectively. In conclusion, this study demonstrated that lignans from P. leptostachya are promising as a novel class of insecticides or insecticide lead compounds for developing botanical pesticides.

Design of a microfluidic device for the measurement of the elastic modulus of deformable particles.

A microfluidic technique recently proposed in the literature to measure the interfacial tension between a liquid droplet and an immiscible suspending liquid [Hudson et al., Appl. Phys. Lett., 2005, 87, 081905], [Cabral and Hudson, Lab Chip, 2006, 6, 427] is suitably adapted to the characterization of the elastic modulus of soft particles in a continuous-flow process. A microfluidic device consisting of a cylindrical pipe with a reduction in cross-section is designed, and the deformation and velocity of incompressible elastic particles suspended in a Newtonian liquid are tracked as they move along the centerline through the constriction. Kinematic and shape information is exploited to calculate the particle's elastic modulus by means of the theory of elastic particle deformation in extensional flow. The approach is validated for different orders of magnitude of the elastic capillary number through experiments and numerical simulations.

Induced-fit adsorption of diol-based porous organic polymers for tetracycline removal.

Adsorption is recognized as one of the most efficient approaches for antibiotics removal from water. Inspired by the enzyme-substrate interaction model, we proposed induced-fit adsorption (IFA) model, and rationally designed and fabricated diol-based porous organic polymers (POPs) as adsorbents for tetracycline (TC) removal. For 2,3-naphthalenediol-based POP (NTdiol-POP), the preferable geometry of diol-groups contributed to the high binding energy with TC species and flexible methylene linkages between neighboring rigid naphthalene rings gave rise to precisely matching between TC species and adsorbents, that is, the induced-fit conformation change. As a result, NTdiol-POP exhibited a high saturated adsorption capacity of 155.8 mg g-1. More importantly, NTdiol-POP exhibited excellent TC removal efficiencies in both concentrated solution (96% for 4 p.p.m) and trace level solution (97% for 250 p.p.b).

Protecting the Li-Metal Anode in a Li-O2 Battery by using Boric Acid as an SEI-Forming Additive.

The Li-O2 battery (LOB) is considered as a promising next-generation energy storage device because of its high theoretic specific energy. To make a practical rechargeable LOB, it is necessary to ensure the stability of the Li anode in an oxygen atmosphere, which is extremely challenging. In this work, an effective Li-anode protection strategy is reported by using boric acid (BA) as a solid electrolyte interface (SEI) forming additive. With the assistance of BA, a continuous and compact SEI film is formed on the Li-metal surface in an oxygen atmosphere, which can significantly reduce unwanted side reactions and suppress the growth of Li dendrites. Such an SEI film mainly consists of nanocrystalline lithium borates connected with amorphous borates, carbonates, fluorides, and some organic compounds. It is ionically conductive and mechanically stronger than conventional SEI layer in common Li-metal-based batteries. With these benefits, the cycle life of LOB is elongated more than sixfold.

Si@C Microsphere Composite with Multiple Buffer Structures for High-Performance Lithium-Ion Battery Anodes.

In this work, a Si@C microsphere composite with multiple buffer structures is prepared by hydrothermal treatment to solve the fatal drawbacks of serious pulverization and low electronic conductivity of Si anodes. By virtue of ferric citrate being the carefully chosen coating carbon source, the silicon nanoparticles with a SiOx layer are encapsulated by the homogeneous mesoporous carbon layer. The SiOx layer with appropriate toughness can primarily suppress the volume expansion of silicon. The plentiful mesopores in the carbon layer and the framework formed by carbon nanotubes with good mechanical strength can effectively buffer and accommodate the volume change of silicon, and greatly improve the infiltration of the electrolyte to the anode. Meanwhile, the mesoporous carbon and carbon nanotube network also enhance the conductivity of the composite. Therefore, the Si@C electrodes exhibit a high initial charge/discharge capacity of 2956/4197 mAh g-1 at a current density of 0.42 A g-1 , excellent rate capability, and outstanding cycle performance up to 800 cycles by virtue of the multiple buffer structures.