Sustained Release-Driven Interface Engineering Enables Fast Charging Lithium Metal Batteries.

LiNO3 has attracted intensive attention as a promising electrolyte additive to regulate Li deposition behavior as it can form favorable Li3N, LiNxOy species to improve the interfacial stability. However, the inferior solubility in carbonate-based electrolyte restricts its application in high-voltage Li metal batteries. Herein, an artificial composite layer (referred to as PML) composed of LiNO3 and PMMA is rationally designed on Li surface. The PML layer serves as a reservoir for LiNO3 release gradually to the electrolyte during cycling, guaranteeing the stability of SEI layer for uniform Li deposition. The PMMA matrix not only links the nitrogen-containing species for uniform ionic conductivity but also can be coordinated with Li for rapid Li ions migration, resulting in homogenous Li-ion flux and dendrite-free morphology. As a result, stable and dendrite-free plating/stripping behaviors of Li metal anodes are achieved even at an ultrahigh current density of 20 mA cm-2 (>570 h) and large areal capacity of 10 mAh cm-2 (>1200 h). Moreover, the Li||LiFePO4 full cell using PML-Li anode undergoes stable cycling for 2000 cycles with high-capacity retention of 94.8%. This facile strategy will widen the potential application of LiNO3 in carbonate-based electrolyte for practical LMBs.

Modulating Surface Architecture and Electronic Conductivity of Li-rich Manganese-Based Cathode.

Li-rich manganese-based cathode (LRMC) has attracted intense attention to developing advanced lithium-ion batteries with high energy density. However, LRMC is still plagued by poor cyclic stability, undesired rate capacity, and irreversible oxygen release. To address these issues, herein, a feasible polyvinylidene fluoride (PVDF)-assisted interface modification strategy is proposed for modulating the surface architecture and electronic conductivity of LRMC by intruding the F-doped carbon coating, spinel structure, and oxygen vacancy on the LRMC, which can greatly enhance the cyclic stability and rate capacity, and restrain the oxygen release for LRMC. As a result, the modified material delivers satisfactory cyclic performance with a capacity retention of 90.22% after 200 cycles at 1 C, an enhanced rate capacity of 153.58 mAh g-1 at 5 C and 126.32 mAh g-1 at 10 C, and an elevated initial Coulombic efficiency of 85.63%. Moreover, the thermal stability, electronic conductivity, and structure stability of LRMC are also significantly improved by the PVDF-assisted interface modification strategy. Therefore, the strategy of simultaneously modulating the surface architecture and the electronic conductivity of LRMC provides a valuable idea to improve the comprehensive electrochemical performance of LRMC, which offers a promising reference for designing LRMC with high electrochemical performance.

Enabling Rapid and Stable Sodium Storage via a P2-Type Layered Cathode with High-Voltage Zero-Phase Transition Behavior.

Currently, a major target in the development of Na-ion batteries is the concurrent attainment of high-rate capacity and long cycling stability. Herein, an advanced Na-ion battery with high-rate capability and long cycle stability based on Li/Ti co-doped P2-type Na0.67Mn0.67Ni0.33O2, a host material with high-voltage zero-phase transition behavior and fast Na+ migration/conductivity during dynamic de-embedding process, is constructed. Experimental results and theoretical calculations reveal that the two-element doping strategy promotes a mutually reinforcing effect, which greatly facilitates the transfer capability of Na+. The cation Ti4+ doping is a dominant high voltage, significantly elevating the operation voltage to 4.4 V. Meanwhile, doping Li+ shows the function in charge transfer, improving the rate performance and prolonging cycling lifespan. Consequently, the designed P2-Na0.75Mn0.54Ni0.27Li0.14Ti0.05O2 cathode material exhibits discharge capacities of 129, 104, and 85 mAh g- 1 under high voltage of 4.4 V at 1, 10, and 20 C, respectively. More importantly, the full-cell delivers a high initial capacity of 198 mAh g-1 at 0.1 C (17.3 mA g-1) and a capacity retention of 73% at 5 C (865 mA g-1) after 1000 cycles, which is seldom witnessed in previous reports, emphasizing their potential applications in advanced energy storage.

Concentration-Gradient Structural LiFe0.5Mn0.5PO4/C Prepared via Co-precipitation Reaction for Advanced Lithium-Ion Batteries.

The intrinsically low electronic conductivity and slow ion diffusion kinetics limit further development of olivine LiFexMn1-xPO4 cathode materials. In this paper, with the aim of improving the performance of such materials and alleviating the Jahn-Taller effect of Mn3+ ion, a bimetallic oxalate precursor with gradient distribution of elemental concentration followed with an efficient process is applied to synthesize LiFe0.5Mn0.5PO4 nanocomposite. The results shown that with certain structural modulation of the precursor, the discharge capacity of synthesized LiFe0.5Mn0.5PO4 increased from 149 mAh g-1 to 156 mAh g-1 at 0.1 C, the cycling capacity was also remarkably improved. the Fe0.5Mn0.5C2O4 ⋅ 2H2O-1 precursor with gradient distribution of elemental concentration effectively restricts the reaction between electrode material and electrolyte, thereby alleviates the dissolution of Mn3+ ion, reduces the decay of capacity and improves the stability of the material.

A novel ACE inhibitory peptide from Pelodiscus sinensis Wiegmann meat water-soluble protein hydrolysate.

Pelodiscus sinensis meat is a nutritional food and tonic with angiotensin-converting enzyme (ACE) inhibitory activities. To identify the bioactive substances responsible, several bioinformatics methods were integrated to enable a virtual screening for bioactive peptides in proteins identified within a water-soluble protein fraction of Pelodiscus sinensis meat by Shotgun proteomics. The peptides were generated from the identified proteins by in silico proteolysis using six proteases. A comparison of the numbers of proteins suitable for digestion with each enzyme and the iBAQ (intensity-based absolute quantification) values for these proteins revealed that bromelain and papain were the most suitable proteases for this sample. Next, the water solubility, toxicity, and ADMET (absorption/distribution/metabolism/excretion/toxicity) properties of these peptides were evaluated in silico. Finally, a novel ACE inhibitory peptide IEWEF with an IC50 value of 41.33 µM was identified. The activity of the synthesized peptide was verified in vitro, and it was shown to be a non-competitive ACE inhibitor. Molecular docking revealed that IEWEF could tightly bind to C-ACE, and N-ACE with energies less than 0 kJ mol-1, and the peptide IEWEF can form hydrogen bonds with C-ACE and N-ACE respectively. These results provide evidence that bioactive peptides in the water-soluble protein fraction account for (at least) some of the ACE inhibitory activities observed in Pelodiscus sinensis meat. Furthermore, our research provides a workflow for the efficient identification of novel ACE inhibitory peptides from complex protein mixtures.

Identification of Vitis vinifera MYB transcription factors and their response against grapevine berry inner necrosis virus.

BACKGROUND: The myeloblastosis (MYB) superfamily is the largest transcription factor family in plants that play diverse roles during stress responses. However, the biotic stress-responsive MYB transcription factors of the grapevine have not been systematically studied. In China, grapevine berries are often infected with the grapevine berry inner necrosis virus (GINV), which eventually reduces the nutritional quality and commodity value. RESULTS: The present study identified and characterized 265 VvMYB or VvMYB-related genes of the "Crimson seedless" grapevine. Based on DNA-binding domain analysis, these VvMYB proteins were classified into four subfamilies, including MYB-related, 2R-MYB, 3R-MYB, and 4R-MYB. Phylogenetic analysis divided the MYB transcription factors into 26 subgroups. Overexpression of VvMYB58 suppressed GINV abundance in the grapevine. Further qPCR indicated that among 41 randomly selected VvMYB genes, 12 were induced during GINV infection, while 28 were downregulated. These findings suggest that VvMYB genes actively regulate defense response in the grapevine. CONCLUSION: A deeper understanding of the MYB TFs engaged in GINV defense response will help devise better management strategies. The present study also provides a foundation for further research on the functions of the MYB transcription factors.

GLRaV-2 protein p24 suppresses host defenses by interaction with a RAV transcription factor from grapevine.

Grapevine leafroll-associated virus 2 (GLRaV-2) is a prevalent virus associated with grapevine leafroll disease, but the molecular mechanism underlying GLRaV-2 infection is largely unclear. Here, we report that 24-kDa protein (p24), an RNA-silencing suppressor (RSS) encoded by GLRaV-2, promotes GLRaV-2 accumulation via interaction with the B3 DNA-binding domain of grapevine (Vitis vinifera) RELATED TO ABSCISIC ACID INSENSITIVE3/VIVIPAROUS1 (VvRAV1), a transcription factor belonging to the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) superfamily. Salicylic acid-inducible VvRAV1 positively regulates the grapevine pathogenesis-related protein 1 (VvPR1) gene by directly binding its promoter, indicating that VvRAV1 may function in the regulation of host basal defense responses. p24 hijacks VvRAV1 to the cytoplasm and employs the protein to sequester 21-nt double-stranded siRNA together, thereby enhancing its own RSS activity. Moreover, p24 enters the nucleus via interaction with VvRAV1 and weakens the latter's binding affinity to the VvPR1 promoter, leading to decreased expression of VvPR1. Our results provide a mechanism by which a viral RSS interferes with both the antiviral RNA silencing and the AP2/ERF-mediated defense responses via the targeting of one specific host factor.

Effect of the focused gap-plasmon mode on tip-enhanced Raman excitation and scattering.

As a powerful molecular detection approach, tip-enhanced Raman scattering (TERS) spectroscopy has the advantages of nanoscale spatial resolution, label-free detection and high enhancement factor, therefore has been widely used in fields of chemistry, materials and life sciences. A TERS system enhanced by the focused gap-plasmon mode composed of Surface Plasmon Polariton (SPP) focus and the metal probe has been reported, however, its underlying enhancement mechanism for Raman excitation and scattering remains to be deeply explored. Here, we focus on the different performances of optical focus and SPP focus in the TERS system, and verify that the cooperation of these two focuses can produce maximum enhancement in a local electromagnetic field. Further, the Purcell effect on sample scattering in such a system is studied for the enhancement of Raman scattering collection in the far field. Finally, the local field enhancement and the sample far-field scattering enhancement are combined to show a full view of the whole process of TERS enhancement. This research can be applied to optimize the excitation and collection of Raman signals in TERS systems, which is of great value for the research and development of TERS technology.

Unveiling the Role and Mechanism of Nb Doping and In Situ Carbon Coating on Improving Lithium-Ion Storage Characteristics of Rod-Like Morphology FeF3 ·0.33H2 O.

Given the inherent characteristics of transition metal fluorides and open tunnel-type frameworks, intercalation-conversion-type FeF3 ·0.33H2 O has attracted widespread attention as a promising lithium-ion battery cathode material with high operating voltage and high energy density. However, its low electronic conductivity and poor structural stability impede its practical application in high-rate capacity and long-lifetime batteries. Herein, rod-like Nb-substituted FeF3 ·0.33H2 O (Nb-FeF3 ·0.33H2 O@C) nanocrystals with a carbon coating derived from in situ carbonization in an ionic liquid are deliberately designed and prepared. Based on first-principles calculations and electrochemical analysis, it is shown that substitution of Nb into a proportion of Fe sites can dramatically reduce the total energy of the system and the bandgap, thus boosting the structural stability and electronic conductivity of FeF3 ·0.33H2 O. Simultaneously, the combination of a surface conductive carbon coating and assembly of the nanoparticles into a rod-like mesoporous architecture can produce an omni-directional ion/electron transmission network and a robust 3D composite structure. The Nb-FeF3 ·0.33H2 O@C composite with 3% Nb-doping displays high capacity (583.2 mAh g-1 at 0.2 C), good rate capacity (187.8 mAh g-1 at a high rate of 5.0 C), and excellent long-term cycle stability (160.4 mAh g-1 after 300 long cycles).

Exploring the physicochemical role of Pd dopant in promoting Li-ion diffusion dynamics and storage performance of NbS2 at the atomic scale.

The two-dimensional layered niobium disulfide (NbS2), as a kind of anode material for Li-ion batteries, has received great attention because of its excellent electronic conductivity and structural stability. However, its ionic conductivity is far from desirable. Herein, we have proposed an effective way to acquire the rapid promotion of its Li-ion diffusion dynamics from the palladium doping effect. By first-principle calculations, we firstly investigated quantitative relations among lattice constants, mechanical properties, and Pd-doped concentration (x) for Pd doped NbS2 (PdxNbS2). It is found that the interlayer spacing of PdxNbS2 undergoes dramatic expansion, which contributes to affording its large space for Li-ion storage. And Pd0.25NbS2 has the best ductility, exhibiting its excellent destruction-resistant properties. Among PdxNbS2 (x = 0, 0.083, 0.167, 0.250, 0.333, and 0.417), it is also proved that Pd0.25NbS2 is the easiest to be prepared with the introduction of NbPd3 as the raw material for the Pd-dopant and it also exhibits excellent thermal stability at room temperature (300 K). Most importantly, by analysis with the climbing-image nudged elastic band method (CI-NEB), it is revealed that Pd0.25NbS2 shows the lowest Li-ion diffusion energy barrier of 0.26 eV, which is also much lower than that of NbS2 (0.43 eV). This is attributed to the inductive effect of the Pd-dopant in its layered structure, trying to maintain the Li-S six-coordinated structure at the initial state when Li-ions transfer to the saddle point. Accordingly, it induces a small structural difference in coordinate structures between initial states and transition states. Moreover, Pd0.25NbS2 undergoes a less obvious oxidation and reduction reaction, maintaining its excellent structural stability during Li intercalation/deintercalation. Additionally, the theoretical average voltage of Pd0.25NbS2 (1.75 V for Li0.75Pd0.25NbS2vs. Li/Li+) is also much lower than that of NbS2 (2.41 V vs. Li/Li+), implying that it can provide a higher power density. Therefore, our theoretical results pave a distinctive way to develop an ultrahigh-rate and long-life anode material for Li-ion batteries.