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The fabrication of low-cost carbon materials and high-performance sodium- and magnesium-ion batteries comprising hierarchical porous electrodes and superior electrolytes is necessary for complementing Li-ion energy storage. In this work, nongraphitic high-surface porous carbons (NGHSPCs) exhibited an unprecedented formation of

Variants of SARS-CoV-2 continue to emerge, posing great challenges in outbreak prevention and control. It is important to understand in advance the impact of possible variants of concern (VOCs) on infectivity and antigenicity. Here, we constructed one or more of the 15 high-frequency naturally occurring amino acid changes in the receptor-binding domain (RBD) of Alpha, Beta, and Gamma variants. A single mutant of A520S, V367F, and S494P in the above three VOCs enhanced infectivity in ACE2-overexpressing 293T cells of different species, LLC-MK2 and Vero cells. Aggregation of multiple RBD mutations significantly reduces the infectivity of the possible three VOCs. Regarding neutralization, it is noteworthy that E484K, N501Y, K417N, and N439K predispose to monoclonal antibodies (mAbs) protection failure in the 15 high-frequency mutations. Most importantly, almost all possible VOCs (single RBD mutation or aggregation of multiple mutations) showed no more than a fourfold decrease in neutralizing activity with convalescent sera, vaccine sera, and immune sera of guinea pigs with different immunogens, and no significant antigenic drift was formed. In conclusion, our pseudovirus results could reduce the concern that the aggregation of multiple high-frequency mutations in the RBD of the spike protein of the three VOCs would lead to severe antigenic drift, and this would provide value for vaccine development strategies.

Highly reversible oxygen redox chemistry of Li2RuO3 enabled by a stabilizing electrode–electrolyte interphase with sulfide solid electrolyte.

Properties of interphases formed between the cathode and the sulfide solid electrolyte and interfacial failure mechanisms.

The emergence of Omicron/BA.1 has brought new challenges to fight against SARS-CoV-2. A large number of mutations in the Spike protein suggest that its susceptibility to immune protection elicited by the existing COVID-19 infection and vaccines may be altered. In this study, we constructed the pseudotyped SARS-CoV-2 variant Omicron. The sensitivity of 28 serum samples from COVID-19 convalescent patients infected with SARS-CoV-2 original strain was tested against pseudotyped Omicron as well as the other variants of concern (VOCs, Alpha, Beta, Gamma, Delta) and variants of interest (VOIs, Lambda, Mu). Our results indicated that the mean neutralization ED50 of these sera against Omicron decreased to 66, which is about 8.4-folds compared to the D614G reference strain (ED50 = 556), whereas the neutralization activity of other VOC and VOI pseudotyped viruses decreased only about 1.2–4.5-folds. The finding from our in vitro assay suggest that Omicron variant may lead to more significant escape from immune protection elicited by previous SARS-CoV-2 infection and perhaps even by existing COVID-19 vaccines.

Severe acute respiratory syndrome coronavirus 2 variants have continued to emerge in diverse geographic locations with a temporal distribution. The Lambda variant containing multiple mutations in the spike protein, has thus far appeared mainly in South America. The variant harbours two mutations in the receptor binding domain, L452Q and F490S, which may change its infectivity and antigenicity to neutralizing antibodies. In this study, we constructed 10 pseudoviruses to study the Lambda variant and each individual amino acid mutation's effect on viral function, and used eight cell lines to study variant infectivity. In total, 12 monoclonal antibodies, 14 convalescent sera, and 23 immunized sera induced by mRNA vaccines, inactivated vaccine, and adenovirus type 5 vector vaccine were used to study the antigenicity of the Lambda variant. We found that compared with the D614G reference strain, Lambda demonstrated enhanced infectivity of Calu-3 and LLC-MK2 cells by 3.3-fold and 1.6-fold, respectively. Notably, the sensitivity of the Lambda variant to 5 of 12 neutralizing monoclonal antibodies, 9G11, AM180, R126, X593, and AbG3, was substantially diminished. Furthermore, convalescent- and vaccine-immunized sera showed on average 1.3–2.5-fold lower neutralizing titres against the Lambda variant. Single mutation analysis revealed that this reduction in neutralization was caused by L452Q and F490S mutations. Collectively, the reduced neutralization ability of the Lambda variant suggests that the efficacy of monoclonal antibodies and vaccines may be compromised during the current pandemic.

Rechargeable magnesium batteries (RMB) are one of the utmost promising post-lithium energy storage technologies due to their high theoretical energy density, affordable low cost, and inherent safety with moisture and air. Nonetheless, the research of RMB has been limited due to the low power and reversible energy densities of available cathode materials. Herein, we report a new Mg battery cathode of trigonal Na5V(PO4)2F2 (t­-NVPF) which performs 136 mA h g−1 reversible capacity realizing multi-electron storage through the V4+/V3+ and V5+/V4+ redox couples. After the first reversible cycle MgNa3V(PO4)2F2 is formed. The geometry optimization and energy calculations on the systems MgxNa3V(PO4)2F2 were carried within the density functional theory (DFT) demonstrating Mg insertion can fill the Na6, Na8, and Na9 sites, and evidenced a 1.5 V difference for the same redox couple comparing with the experimental results. Some facets of its crystal and local structure are determined by XRD, EPR, XPS, and 31P and 51V solid-state NMR spectroscopy. The cells cycled 2.5 – 0.2 V vs. Mg2+/Mg and at low current densities exhibited diminished polarization. The average cell potential is 1.4 V, entailing an energy density of 190 W h kg-1­ at the materials’ level. This piece of work provides an effective strategy for designing multi-electron storage for high-energy rechargeable Mg batteries, but more efforts are required to overcome high polarization during charge-discharge cycles which are commonly found in Mg batteries.

Ni-rich materials have received widespread attention as one of the mainstream cathodes in high-energy-density lithium-ion batteries for electric vehicles. However, Ni-rich cathodes suffer from severe surface reconstruction in a high delithiation state, constraining their rate capabilities and life span. Herein, a novel P2-type Na

The growth of sodium dendrites and the associated solid electrolyte interface (SEI) layer is a critical and fundamental issue influencing the safety and cycling lifespan of sodium batteries. In this work, we use in-situ 23Na magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) techniques, along with an innovative analytical approach, to provide space-resolved and quantitative insights into the formation and evolution of sodium metal microstructures (SMSs; that is, dendritic and mossy Na metal) during the deposition and stripping processes. Our results reveal that the growing SMSs give rise to a linear increase in the overpotential until a transition voltage of 0.15 V is reached, at which point violent electrochemical decomposition of the electrolyte is triggered, leading to the formation of mossy-type SMSs and rapid battery failure. In addition, we determined the existence of NaH in the SEI on sodium metal with ex-situ NMR results. The poor electronic conductivity of NaH is beneficial for the growth of a stable SEI on sodium metal. Magnetic resonance imaging and spectroscopy provide quantitative insights into the growth of sodium microstructures in batteries.

In this work, a new fluorophosphate cathode material Na5V(PO4)2F2 for sodium-ion batteries is synthesized by a facile synthetic strategy for the first time. X-ray diffraction analyses indicate that...

Description, Advanced spectroscopy methods quantitatively elucidate the failure process of lithium metal batteries., Practical use of lithium (Li) metal for high–energy density lithium metal batteries has been prevented by the continuous formation of Li dendrites, electrochemically isolated Li metal, and the irreversible formation of solid electrolyte interphases (SEIs). Differentiating and quantifying these inactive Li species are key to understand the failure mode. Here, using operando nuclear magnetic resonance (NMR) spectroscopy together with ex situ titration gas chromatography (TGC) and mass spectrometry titration (MST) techniques, we established a solid foundation for quantifying the evolution of dead Li metal and SEI separately. The existence of LiH is identified, which causes deviation in the quantification results of dead Li metal obtained by these three techniques. The formation of inactive Li under various operating conditions has been studied quantitatively, which revealed a general “two-stage” failure process for the Li metal. The combined techniques presented here establish a benchmark to unravel the complex failure mechanism of Li metal.

Emerging SARS-CoV-2 variants are the most serious problem for COVID-19 prophylaxis and treatment. To determine whether the SARS-CoV-2 vaccine strain should be updated following variant emergence like seasonal flu vaccine, the changed degree on antigenicity of SARS-CoV-2 variants and H3N2 flu vaccine strains was compared. The neutralization activities of Alpha, Beta and Gamma variants’ spike protein-immunized sera were analysed against the eight current epidemic variants and 20 possible variants combining the top 10 prevalent RBD mutations based on the Delta variant, which were constructed using pseudotyped viruses. Meanwhile, the neutralization activities of convalescent sera and current inactivated and recombinant protein vaccine-elicited sera were also examined against all possible Delta variants. Eight HA protein-expressing DNAs elicited-animal sera were also tested against eight pseudotyped viruses of H3N2 flu vaccine strains from 2011–2019. Our results indicate that the antigenicity changes of possible Delta variants were mostly within four folds, whereas the antigenicity changes among different H3N2 vaccine strains were approximately 10–100-fold. Structural analysis of the antigenic characterization of the SARS-CoV-2 and H3N2 mutations supports the neutralization results. This study indicates that the antigenicity changes of the current SARS-CoV-2 may not be sufficient to require replacement of the current vaccine strain.

The SARS-CoV-2 virus has had a major impact on global human health. During the spread of SARS-CoV-2, weakened host immunity and the use of vaccines with low efficacy may result in the development of more virulent strains or strains with resistance to existing vaccines and antibodies. The prevalence of SARS-CoV-2 mutant strains differs among regions, and this variation may affect the effectiveness of vaccines. In this study, an epidemiological investigation of SARS-CoV-2 in Portugal was performed, and the VSV-ΔG-G* pseudovirus system was used to construct 12 S protein epidemic mutants, D614G, A222V+D614G, B.1.1.7, S477N+D614G, P1162R+D614G+A222V, D839Y+D614G, L176F+D614G, B.1.1.7+L216F, B.1.1.7+M740V, B.1.258, B.1.258+L1063F, and B.1.258+N751Y.The mutant pseudoviruses were used to infect four susceptible cell lines (i.e., Huh7, hACE2-293T, Vero, and LLC-MK2) and 14 cell lines overexpressing ACE2 from different species. Mutant strains did not show increased infectivity or cross-species transmission. Neutralization activity was evaluated using the newly constructed pseudoviruses, mouse serum, and 11 monoclonal antibodies. The neutralizing activity in immunized mouse serum was not significantly reduced for the mutant strains. Additionally, mutant strains in Portugal showed escape from 9 of 11 monoclonal antibodies. Neutralization resistance was mainly caused by the S477N, N439K, and N501Y mutations in the Spike receptor binding domain. These findings emphasize the importance of SARS-CoV-2 mutation tracking in different regions for epidemic prevention and control.

As one of the key electrode materials for alkaline-ion rechargeable batteries, lithium- and sodium-ion containing oxide-based materials play an important role in determining the energy density, cyclic stability, and rate capability of the batteries. However, their performance has yet to meet society's demands for fast-growing portable electronics, or as power battery for electric vehicles (EVs) and storage battery for smart grids. Advanced characterization techniques are very powerful tools for understanding the complex structural evolutions and their correlation with the electrochemical performance of cathode materials in rechargeable batteries. Specially, solid-state nuclear magnetic resonance (ssNMR) spectroscopy plays a crucial role in systematically understanding the local structural evolutions, structure–property relationship, and decay mechanism of electrode materials. In this chapter, we highlight the ssNMR applications in the oxide-based cathodes for both lithium and sodium ions batteries. Specifically, we discuss structural features and electrochemical properties of various typical layered oxides materials at the beginning of each sub-section, followed by addressing the unique advantages of ssNMR using specific examples.

Oxide-type solid state electrolytes are considered to be a promising solid state electrolyte in all solid state batteries due to their relatively high ionic conductivity, wide potential window, and excellent thermal stability. However, many issues associated with their practical applications in all solid state batteries have yet to be solved, and their underlying mechanisms have not been fully understood. Thus, advanced techniques are called on to analyse these issues. Solid state nuclear magnetic resonance (ssNMR), with its ability to probe local structure, to track ionic motion in different length/time scales, to study lithium/sodium dendrites, and to investigate interfacial issues, has unique advantages in characterizing such oxide-type solid state batteries. In this chapter, we first summarize the state-of-the art applications of ssNMR in the oxide-type solid state batteries mainly including garnet-type and NASICON-type. After that, we also present some perspectives on the employment of ssNMR in oxide-type solid state batteries.

SARS-CoV-2 has caused the COVID-19 pandemic. Recently, B.1.617 variants have been transmitted rapidly in India. The transmissibility, pathogenicity, and neutralization characteristics of these variants have received considerable interest. In this study, 22 pseudotyped viruses were constructed for B.1.617 variants and their corresponding single amino acid mutations. B.1.617 variants did not exhibit significant enhanced infectivity in human cells, but mutations T478K and E484Q in the receptor binding domain led to enhanced infectivity in mouse ACE2-overexpressing cells. Furin activities were slightly increased against B.1.617 variants and cell–cell fusion after infection of B.1.617 variants was enhanced. Furthermore, B.1.617 variants escaped neutralization by several mAbs, mainly because of mutations L452R, T478K, and E484Q in the receptor binding domain. The neutralization activities of sera from convalescent patients, inactivated vaccine-immunized volunteers, adenovirus vaccine-immunized volunteers, and SARS-CoV-2 immunized animals against pseudotyped B.1.617 variants were reduced by approximately twofold, compared with the D614G variant.

Na3VCr(PO4)3 has attracted great attention due to its high energy density and stable structure. The substitution of vanadium with chromium led to an increase in the redox potential from 3.4 to 4.2 V (vs. Na+/Na). In this work, the electrochemical performance of Na3VCr(PO4)3 (NVCP) in Mg cells is successfully investigated. Reversible multielectron Mg2+/Na+ extraction/insertion is observed. Upon charging, NVCP exhibits two plateaus at 1.75 V and 2.3 V vs. Mg2+/Mg0 achieving a maximum reversible capacity of 85 mA h g−1 (a 1.45 electron reaction) enabling oxidation to VV as determined by 51V NMR and XPS, and accompanied by extraction of sodium from Na2 sites according to 23Na NMR. During the subsequent cycles Mg2+/Na+ ions react at 2.3 and 1.7 V, and an additional peak of Mg2+ at 1.2 V is observed. Alternatively, electrochemical cells were also assembled with activated carbon in a 0.1 M Mg(TFSI)2 electrolyte, leading to similar profiles and capacity even at higher current density. Finally, the chemical desodiation of NVCP using I2, Cl2 and NO2BF4 is performed to avoid mobile sodium ions. XRD, XPS and 51V NMR confirmed the contraction of the cell and the oxidation to VIV and VV. Iodine was not capable of full sodium extraction. Despite this fact, the ability of this sample to retain 65 mA h g−1 during a few cycles evidences the reversibility of magnesium insertion. The use of stronger oxidants such as Cl2 or NO2BF4 allowed the increase of the initial OCV and resulted in a plateau at 4 V. The chemical desodiation was also accompanied by an enhanced capacity decrease which could be correlated with the structural degradation.

Enhancing the electrochemical performance of batteries, including the lifespan, energy, and power densities, is an everlasting quest for the rechargeable battery community. However, the dynamic and coupled (electro)chemical processes that occur in the electrode materials as well as at the electrode/electrolyte interfaces complicate the investigation of their working and decay mechanisms. Herein, the recent developments and applications of solid-state nuclear magnetic resonance (ssNMR) and magnetic resonance imaging (MRI) techniques in Li/Na batteries are reviewed. Several typical cases including the applications of NMR spectroscopy for the investigation of the pristine structure and the dynamic structural evolution of materials are first emphasized. The NMR applications in analyzing the solid electrolyte interfaces (SEI) on the electrode are further concluded, involving the identification of SEI components and investigation of ionic motion through the interfaces. Beyond, the new development of in situ NMR and MRI techniques are highlighted, including their advantages, challenges, applications and the design principle of in situ cell. In the end, a prospect about how to use ssNMR in battery research from the perspectives of materials, interface, and in situ NMR, aiming at obtaining deeper insight of batteries with the assistance of ssNMR is represented.

we revive the application of operando NMR technique in the study of LMBs. The combination of AFBs and operando NMR completely avoid the interference of lithium metal anode on the analysis of electrochemistry related Li metal, and thus observe the deposition and dissolution processes of lithium metal during cycling in real-time. Combining with the practical battery configuration and the novel data-processing method, we can operando monitor the evolution of capacity loss caused by the dead Li metal and SEI during the whole cycling process

A new compound Na3V3(PO4)4 is successfully synthesized for sodium ion batteries using a sol–gel method. Composition analysis through ICP-OES confirms the stoichiometry of Na3V3(PO4)4. Structural analysis based on XRD reveals that the new material crystallizes in a monoclinic system with a C2/c space group. The new compound exhibits a layered structure containing 3D Na+ ion channels allowing excellent cycling and rate performance. Even at a high current rate of 3C (1C = 45 mA/g), it still delivers 82% of the theoretical capacity. Meanwhile, 92% of its capacity is retained after 100 electrochemical cycles. The voltage profiles of Na3V3(PO4)4 show that it can reversibly uptake nearly one Na+ ion with a 3.9 V voltage plateau, which is the highest value among Na-containing V-based orthophosphates ever reported.

Mn-based layered oxides as one of the most promising and cost-effective cathode candidates for sodium-ion batteries still face great challenge to achieve high capacity with long cycle life under high-rate current simultaneously. In this work, we propose an effective strategy by a combination of liquid N2 quenching and aliovalent doping to get new layered cathode materials. As evidenced by in-situ synchrotron X-ray diffraction, time-of-flight powder neutron diffraction and solid-state 23Na nuclear magnetic resonance techniques, the proposed synthesis methods allow tuning the transition metal ions vacancies and enhance Mn4+/Mn3+ redox center of P2-type Mn-based materials. Our results demonstrate that such an optimized structure significantly enhances the deliverable capacity, Na+ mobility and electronic conductivity of the materials. Furthermore, the effects of aliovalent doping elements and different cooling approaches on the long-range structure, local environment and electrochemical performance are comprehensively studied by comparing a wide range of doped Na0.67MxMn1-xO2 (M = Li, Mg, Al, Fe) materials. The optimized Na0.67Al0.1Fe0.05Mn0.85O2 material exhibits a remarkably high initial capacity of 202 mAh g−1 among ever reported P2-type layered oxides within 2–4 V, a stable capacity retention of 81% after 600 cycles and outstanding rate capability of the specific capacity up to 122 mAh g−1 at 1200 mA g−1.

Realization of multi-electron reactions per transition metal is an effective strategy to increase the energy density of cathode materials, and comprehensively understanding of their underlying mechanism is necessary to further improve the electrochemical performance of the sodium-ion batteries. Here, we investigate and realize multi-electron reactions in NaVOPO4, which could deliver very high specific capacity. In addition, we explore its electrochemical mechanism in great detail by a series of advanced techniques, including XANES, in situ SXRD, 23Na, 31P, and 51V solid state NMR. The results demonstrate that V3−δ/V4+/V5+ redox couples can be realized in NaVOPO4, and a biphasic transition followed by a monophasic reaction process occurred during discharge process. Finally, the causes of battery failure are analyzed and corresponding strategies to improve electrochemical performance of NaVOPO4 are discussed.

Na3V(PO4)2 was reported recently as a novel cathode material with high theoretical energy density for Sodium-ion batteries (SIBs). However, whether V3+/V4+/V5+ multielectron reactions can be realized during the charging process is still an open question. In this work, Na3V(PO4)2 is synthesized by using a solid-state method. Its atomic composition and crystal structure are verified by X-ray diffraction (XRD) and neutron diffraction (ND) joint refinement. The electrochemical performance of Na3V(PO4)2 is evaluated in two different voltage windows, namely 2.5&ndash, 3.8 and 2.5&ndash, 4.3 V. 51V solid-state NMR (ssNMR) results disclose the presence of V5+ in Na2&minus, xV(PO4)2 when charging Na3V(PO4)2 to 4.3 V, confirming Na3V(PO4)2 is a potential high energy density cathode through realization of V3+/V4+/V5+ multielectron reactions.