NA Cells Research Articles

Simultaneous Regulation of Organic and Inorganic Components in Interphase by Fiber Separator for High-Stable Sodium Metal Batteries.

Uncontrollable side reactions at the metal interface have been identified as the root cause of the formation of a fragile solid electrolyte interphase, leading to irreversible sodium loss in sodium metal batteries. Here, we proposed an interface engineering strategy that employed a carboxyl functionalized cellulose separator to provide strong dipole moments and induce the cleavage of P-F bond to construct a solid electrolyte interphase (SEI) rich in NaF. In addition, we employed nuclear magnetic resonance technology confirmed that the separator with strong dipole moments prevented the reduction of organic solvents by attracting electrons, thereby inhibiting the formation of organic oligomers. SEI with high NaF content and few oligomers is smooth and robust, obviously decreasing the interface impedance of the Na anode. The symmetric Na||Na cells, equipped with the functionalized separator, efficiently operated for 1400 hours with a stable 72 mV overpotential at 0.25 mA cm-2, exhibiting low energy barrier and fast ion transport kinetics. The Na||Na3V2(PO4)3 cell also showed stable cycling performance, with the capacity remaining at 94.83 % of the initial capacity after 1000 cycles at 1C. The proposed separator could control the formation and composition of SEI, paving the way for the development of long-life sodium metal batteries.

A robust 3D nanostructured composite polymer electrolyte with novel dual-ion channels toward solid-state sodium metal batteries

The high energy density and low cost of sodium metal batteries enable them to be the rising star of next-generation batteries. However, the growth of sodium dendrites and the high activity of sodium metal may lead to significant safety risks for liquid sodium metal batteries. Composite polymer electrolytes (CPEs), which combine the advantages of inorganic solid-state electrolyte and solid-state polymer electrolytes, have become a promising candidate to replace liquid electrolytes. In this study, a novel Na-beta-Al2O3/polyacrylonitrile (PAN) CPE with a 3D network nanostructure (NAP) has been synthesized by electrospinning method. NAP membrane provides synergistic dual-ion channels for the migration of sodium ions, exhibiting ionic conductivity of 7.22 × 10−4 S cm−1, a sodium-ion transport number of 0.73, and an electrochemical stabilization window as high as 4.92 V. Compared with pure PAN, NAP presents enhanced mechanical strength, superior electrochemical properties and interfacial stability. NAP-based sodium symmetric cell achieves stable plating and stripping for 800 h. At room temperature, the capacity retention ratios of NAP-based Na3V2(PO4)3//Na cell are 92.02% (0.2 C, 200 cycles) and 73.10% (0.5 C, 1000 cycles), respectively. The capacity retention is 72.49% after 250 cycles at 0.5 C and a high temperature of 60 °C. X-ray photoelectron spectroscopy spectra indicate that solid electrolyte interphase formed in NAP-based battery contains higher NaF component, R–(CO)O–Na content and interfacially favorable organic components, which are beneficial to accelerate the sodium-ion transfer at the interface. This work provides new insights into the construction of 3D nanostructured CPEs with fast ion transport for solid-state sodium metal batteries.

Unlocking the Multi-Redox (Nb5+/Nb4+/Nb3+) Reactions in Nasicon- Nb2(PO4)3 Anode for Li- and Na-Ion Batteries

NASICON (Natrium Super-Ionic CONductor) type materials are known for their high structural, and thermal stability and superior sodium ion mobility which make this framework an efficient electrode material for Na-ion batteries.1 In recent times NASICON-type compounds have been widely explored as Li- and Na-ion cathodes and solid-state electrolytes but are largely ignored as anodes due to their lower capacities and higher intercalation voltages, which reduce the overall energy densities of Li- and Na-ion batteries (LIBs and SIBs). NASICON structure has a general molecular formula of NaxMM′(PO4)3, where two MO6 octahedra corners are shared with three PO4 tetrahedra along the c-direction resulting in the “lantern units” and each lantern unit joins six other lantern units, generating a large interstitial space that can accommodate up to four alkali cations per formula unit.2 In the NASICON family usually all members contain Na/Li ions in terms of synthesis and electrochemical/chemical oxidation routes must be employed to remove the Na from the parent compound.Herein, for the first time we will present a comprehensive study on the structural and electrochemical properties of the empty NASICON-type (contains no Li or Na ions in its pristine state) mixed valance Nb2(PO4)3 and its potential application as an anode in LIBs and SIBs. Due to the multi-redox activity of Nb, it is possible to attain high insertion capacity (~ 150 mAh g-1 for SIBs and ~ 170 for LIBs) and relatively lower voltages (1.8 V vs. Li+/Li0 and 1.4 V vs. Na+/Na0) compared to Ti or V-based NASICON anodes.3,4 Our in-situ XRD measurements revealed multiple-phase transformations during Li and Na intercalation with the formation of short-range ordered Li3Nb2(PO4)3 and triclinic (P-1)-Na3Nb2(PO4)3 at the end of discharge. The distinct electrochemical Li and Na intercalation behavior of the Nb2(PO4)3 anode can be ascribed to the relative differences in size, filling of crystallographic sites, and chemical characters of Li and Na ions. Our density functional theory calculations are also in agreement with the in-situ XRD measurements in predicting a stable Na3Nb2(PO4)3 composition in the Na-Nb2(PO4)3 pseudo-binary system. X-ray absorption spectroscopy confirms the participation of multi-redox Nb5+/Nb4+/Nb3+ couples. Although the micron-sized anode showed moderate storage capacities (~106 and 84 mAh g-1 for Li and Na cells, respectively) at 1C rate after 200 cycles, further optimization of electrode and electrolytes is expected to produce better performance. In the future, pairing Nb2(PO4)3 anode with suitable cathodes can enable high-energy density batteries.5

A weakly coordinating-intervention strategy for modulating Na+ solvation sheathes and constructing robust interphase in sodium-metal batteries

Constructing powerful anode/cathode interphases by modulate ion solvation structure is the principle of electrolyte design. However, the methodological and theoretical design principles of electrolyte/solvation structure and their effect on electrochemical performance are still vague. Here, we propose a cationic weakly coordinating-intervention strategy for modulating the Na+ solvation sheathes and constructing robust anode/cathode interphases in sodium-metal batteries. Unlike the local highly concentrated electrolytes, 1,2-difluorobenzene can weakly coordinate with Na+ thus transforming the solvation structure into Na+-anion-incorporated structures and strengthening anode/cathode interphases formation by combining with salt decomposition. Furthermore, the correlations between the electrode interface properties and solvation structure are revealed, which can be tuned by the weakly coordination. Ultimately, the modulated electrolyte achieves 97.5% Coulombic efficiency for 600 cycles in Na‖Cu cells at 1 mA cm−2 and a beneficial lifetime (2500 h) in Na‖Na cells. Meanwhile, Na‖PB cells have achieved long-term operation at 4.8 V, along with operation at wide temperatures.

Recent Progress in Developing High-Performance Anode Materials for Next-Generation Sodium-Ion Batteries

Rechargeable lithium-ion batteries (LIBs) have attracted great attention due to their large-scale energy storage applications such as electric vehicles (EVs) and grid-scale energy storage systems (ESSs). The ongoing transition towards EVs has accelerated ever-increasing demand for LIBs that causes the shortage of lithium metal resources and their expensive price. Therefore, great efforts have been made to exploit an alternative system that replaces the conventional LIBs. While sodium-ion batteries (SIBs) can be the most evident alternatives to LIBs based on the natural abundance and low cost of sodium resources, the major scientific challenges reside in developing the new anode materials due to the poor performance of conventional LIB anodes in Na cells, such as graphite and silicon. This article reviews the potential of SIBs as promising alternatives to LIBs and recent progress in developing high-performance anode materials for SIBs. The strengths and drawbacks of recently developed anode materials have been discussed, including graphite, hard carbon, silicon, phosphorus, and other transition metal compounds such as oxides, phosphides, and sulfides.

Immunogenicity evaluation of a bivalent vaccine based on a recombinant rabies virus expressing gB protein of FHV-1 in mice and cats

Feline viral rhinotracheitis (FVR) is caused by the feline herpesvirus-1 (FHV-1), which commonly results in upper respiratory symptoms, and can result in death in the kittens and weak cats. Rabies is an infectious disease with zoonotic characteristics highly relevant to public health and also poses a serious threat to cats. Vaccines are the most effective method to control the spread of both FHV-1 and RABV and have the advantage that they produce long-term specific immune responses. In this study, we constructed a bivalent vaccine against FHV-1 and rabies virus (RABV) simultaneously. The vaccine was constructed by cloning FHV-1 gB into a RABV based vector, and the recombinant RABV (SRV9-FHV-gB) expressing the FHV-1 gB protein was rescued. The growth characteristics of SRV9-FHV-gB were analyzed on NA and BSR cells. To assess the immunogenicity of the vaccine, mice and cats were immunized with SRV9-FHV-gB supplemented with Gel02 adjuvant.The SRV9-FHV-gB exhibited the same growth characteristics as the parent virus SRV9 in both BSR cells and NA cells. The safety of SRV9-FHV-gB was evaluated using 5-day-old and 14-day-old suckling mice. The results showed that mice infected with the SRV9-FHV-gB survived for longer than those in the SRV9 group. Mice immunized with inactivated SRV9-FHV-gB produced high titers of specific antibodies against FHV-1 and neutralizing antibodies against RABV. Cats that received three immunizations with SRV9-FHV-gB also produced neutralizing antibodies against both FHV-1 and RABV. This study represents the first time that a bivalent vaccine targeting FHV-1 and RABV has been constructed, laying the foundations and providing inspiration for the development of other multivalent vaccines.

Weakly Polar Ether‐Aided Ionic Liquid Electrolyte Enables High‐Performance Sodium Metal Batteries over Wide Temperature Range

AbstractSodium (Na) metal batteries (SMBs) have attracted many attentions because of high specific capacity and low redox potential. However, SMBs encounter several crucial challenges including Na dendrites growth, severe interfacial side reactions and safe issues from liquid organic electrolyte. In this study, a non‐flammable 1,2‐bis (1,1,2,2‐tetrafluoroethoxy) ethane (TFEE) aided ionic liquid (IL) electrolyte (TILE) is reported with sodium bis(trifluoromethylsulfonyl)imide (NaTFSI) salt and N‐methyl‐N‐propylpyrrolidinium bis(fluorosulfonyl)imide ([Py13][FSI]) IL solvent. The IL solvent contains plentiful organic cations and anions, which helps to provide a cationic shielding effect by [Py13]+ cations and regulate the Na+ solvation structure with more FSI− and TFSI− anions. The unique solvation structure of Na+ facilitates a stable inorganic‐rich solid electrolyte interphase (SEI), effectively inhibiting unstable Na deposition and suppressing side reactions between the electrolyte and Na‐metal in SMBs. Therefore, the Na3V2(PO4)3 (NVP)||Na cells with TILE can deliver good rate capability and superior cycling performance with capacity retention of 95.5% and Coulombic efficiency of ≈99.9% after 2000 cycles at 5C rate and 25 °C. The high‐voltage NaNi0.33Fe0.33Mn0.33O2(NFM)||Na cells with TILE can also deliver good cycling performance with capacity retention of 92% after 150 cycles in the voltage range of 2.0–4.1 V at 0.5C rate and 25 °C.

Low-temperature synthesis in the dittmarite–sodium acetate trihydrate system: electrochemical activity of M3+/M2+ redox couples in AMPO4 (A = Na, Li; M = Mn, Mn/Fe)

Phase-pure NaMPO4 (M = Mn, Mn/Fe; isotypic to triphylite) and Li(Mn/Fe)PO4 were isolated as a result of the low- temperature reaction between NH4MPO4·H2O (M = Mn, Mn/Fe) and AcONa·3H2O or AcOLi, respectively. Electrochemical tests in half-cells revealed that Na-based compounds exhibit poor electrochemical activity vs. metallic Na, while the similarly synthesized Li counterpart demonstrates decent cycling in Na cells. The synthetic features, crystal structures and properties of related members of the olivine family are discussed.

K x Mn[Mn(CN)6] as a High Capacity Positive Electrode Material for Potassium Batteries

Recently, Na-ion and K-ion batteries have attracted attention as next-generation secondary batteries.1 Prussian blue analogues (PBAs) are promising cathode materials for these batteries. In 2014, it was reported that Na x Mn[Mn(CN)6] exhibited higher capacity in Na cells than the theoretical capacity based on Mn2+/3+ redox, which could be attributed to the reduction of Mn in [Mn(CN)6] to monovalence.2 Thus, PBA with Mn at the C-coordination site exhibits unique properties, but there is no report of high capacity in K cells. In this study, K x Mn[Mn(CN)6] (KMnHCM) was synthesized, and K+ ion extraction/insertion properties were evaluated. KMnHCM was synthesized by the solution precipitation method.3 The solution was sufficiently deoxygenated by bubbling nitrogen gas, and synthesis was performed under N2 atmosphere. The obtained samples were washed three times with deionized water under N2 atmosphere, and then dried at 150 °C under vacuum. The active material was mixed with conductive carbon (KB) and binder (PVdF) at a weight ratio of 7:2:1 in a glove box under an Ar atmosphere. Galvanostatic charge-discharge tests were conducted in a two-compartment three-electrode cell using a composite electrode coated on an Al foil as the working electrode, an activated carbon counter electrode, and an Ag+/Ag reference electrode. Figure 1(a) shows the X-ray diffraction (SXRD) patterns and Rietveld refinement results of the synthesized sample. The diffraction patterns of KMnHCM can be attributed to the monoclinic structure with space group P21/n and are almost identical to that previously reported. SXRD patterns were successfully fitted with the satisfied R values, and the composition of KMnHCM was estimated to be K1.87Mn[Mn(CN)6]0.96·0.29H2O. Figure 1(b) shows the charge-discharge curves of KMnHCM. The electrode showed an initial charge capacity of 163 mAh g-1 and an initial discharge capacity of 220 mAh g-1, corresponding to respective ~2.0 and 2.76 potassium extraction and insertion, respectively, from/into K x Mn[Mn(CN)6]. The discharge capacity exceeds the theoretical capacity of 160 mAh g-1 based on the Mn2+/3+ redox of K1.87Mn[Mn(CN)6]0.96·0.29H2O. Furthermore, the additional plateau was observed at the low voltage of around 1.5 and 1.7 V in the discharge and charge curves, respectively. The extremely high capacity and the third plateau at low voltage are similar to Na x Mn[Mn(CN)6] in Na cells.2 Thus, the third plateau would be attributed to the reversible redox of [MnII(CN)6]4-⇄[MnI(CN)6]5-. In the talk, we will further discuss the charge-discharge mechanisms, including redox behavior and structural changes of KMnHCM during charge/discharge.

P'2-Na2/3[Mn1-X Sc x ]O2 Electrode in Sodium-Batteries

In recent years, Na-ion batteries (SIB) are expected to be an alternative to Li-ion batteries. One of the cathode materials for SIB is transition metal layered oxides Na x TMO2 (TM = transition metal). In order to improve their capacity, efforts have been made to utilize the redox process(es) of not only TM ions but also oxide ions (oxygen redox). In addition, partial replacement of TMs with electrochemically inactive elements has been investigated to enhance cycle stability. Our group reported P2-type Na x MnMeO2 (Me = Li, Mg) exhibit higher capacity than existing materials via using additional redox of oxide ions (1, 2). Another example delivering high capacity reported in our group is P’2-type Na2/3MnO2, where the average oxidation states of Mn is about +3.37 and a co-operative Jahn-Teller distortion (CJTD) of Mn3+ (t2g 3-eg 1) is shown (3). In this study, we synthesized P’2-Na2/3Mn1-x Sc x O2 and studied the effect of Sc substitution on the electrochemical properties of P’2-Na2/3MnO2. P’2-Na2/3Mn1-x Sc x O2 (x = 0, 0.08, 0.11) samples were synthesized using Na2CO3, Mn2O3, and Sc2O3 as starting materials, based on the synthesis method of the non-doped P’2-Na2/3MnO2 as we previously reported (3). For galvanostatic cycling tests, a working electrode consisted of active materials, acetylene black, and PVdF in 80:10:10 wt.% on Al foil. Na metal was used as a counter electrode, and an electrolyte used was 1.0 mol dm-3 NaPF6 PC solution. XRD patterns of P’2-Na2/3Mn1-x Sc x O2 are shown in Fig. 1 (a). Major diffraction peaks can be indexed as orthorhombic Na2/3MnO2 with space group of Cmcm, confirming P’2-type layered oxides. Note that non-substituted Na2/3MnO2 shows a superstructure peak at 23.9º in 2θ attributed to in-plane superstructure (3). At x = 0.11, impurity of Sc2O3 is observed, indicating that Sc is substituted for Mn up to about 8% in P’2-Na2/3MnO2. Sc3+ ions which has a large ionic radius than Mn3+ ions and no Jahn-Teller distortion, resulted in the enlarged lattice constant a (Figure 1 (a), inset) and the reduced lattice distortion (4). Fig. 1 (b) shows the discharge capacity and the coulombic efficiency of P’2-Na2/3Mn1-x Sc x O2 Electrode in Na cell. The capacity retention after 50 cycles for the non-substituted x = 0 (non-sub) and Sc-substituted x = 0.08 (Sc-sub) in the voltage range of 1.5 – 4.4 V was 66.4% and 85.4%, respectively. In-situ XRD data can support better cycling life. The Sc-sub exhibited better rate characteristics than the non-sub, indicating that there is an optimal amount of Sc to improve the electrochemical properties. Looking at the initial charge/discharge curves at different cutoff voltages (Fig. 1 (c)), setting the upper cutoff voltage beyond 3.47 V, causes a significant polarization due to the phase transition from P’2 to OP4. From the cycle stability tests at different upper cutoff voltages (Fig. 1 (d)), the upper cutoff limit of 4.0 V demonstrates notable capacity fade than that of 4.4 V. One possible reasons should be changing the surface chemistry of electrode by applying higher voltage than 4.0 V. We will further discuss the effects of Sc substitution and charge/discharge voltage range on the electrochemical properties.References Yabuuchi, S. Komaba, et al., J. Mater. Chem., 2, 16851 (2014).Yabuuchi, S. Komaba, et al., Adv Energy Mater., 4, 1301453 (2014).Kumakura, S. Komaba, et al., Angew. Chem. Int. Ed., 55, 12760 (2016).S. Kumakura, S. Komaba, et al., Chem Mater., 29, 8958 (2017). Figure 1

Enhancing Structural of P2-Type Layered Cathode Material for Sodium-Ion Batteries through Cu Substitution

Oxygen-redox-based layered cathode materials for Sodium-ion batteries (SIBs) have been recognized as a promising alternative to Lithium-ion batteries (LIBs) due to high energy density and additional capacity in the high voltage. However, their irreversible oxygen-redox activity during cycling leads to structural distortion and capacity fading. Herein, we introduce a layered P2-Na0.75[Li0.15Cu0.15Mn0.7]O2 cathode material, in which Cu substitution improves electro-conductivity and cyclability. Na0.75[Li0.15Cu0.15Mn0.7]O2 delivers a reversible capacity of 170 mAh g-1 at 0.1C in Na cell. Operando-XRD measurement display the material maintain the P2 structure even upon full Na+ extraction and insertion. Furthermore, magnetic susceptibility provide further information Cu2+/Cu3+, Mn3+/Mn4+, and O2-/(O2)n- ion distribution in Na0.75[Li0.15Cu0.15Mn0.7]O2. This research highlight the effect of Li and Cu doping in P2-type layered materials and the contribution of oxygen redox to additional capacity in high voltages, suggesting the potential for future development of cathode materials for Na-ion batteries with oxygen redox.

Construction of an ultra-stable mixed conductive layer to stabilize the solid-state electrolyte/Na interface by in-situ interface chemistry

The quest for high energy density, essentially safe, and cost-effective energy storing systems is powering the evolution of solid-state sodium metal batteries (SSSMBs). However, insufficient Na/solid-state electrolyte (SSE) interface contact leads to the formation of sodium dendrites, causing premature cell failure and safety issues that limit their practical application. Here, a novel ultra-stable mixed conductive layer (MCL) composed of Na15Sn4 and NaF is introduced at the Na|Na3Zr2Si2PO12 (NZSP) interface through in-situ interface chemistry. Such an MCL not only enables the transformation of the NZSP surface from sodiophobic to sodiophilic to achieve intimate contact with Na but also homogenizes the Na+ flux without dendritic sodium. Benefiting from the construction of the multifunctional interface, a high critical current density (CCD) of 1.3 mA cm−2 and an exceptionally long cycle life of 6000 h at 0.3 mA cm−2 are achieved for the Na|SnF2@NZSP|Na cell at room temperature (RT). Furthermore, the Na|SnF2@NZSP|Na3V2(PO4)3 full cell shows excellent cycling performance (91 % of maintained capacity for over 500 cycles at 1 C) and rate capability (101.4 mAh/g at 5 C) at RT. This work presents a validated method for the coordinated regulation of interfacial transfer kinetics and inhibition of sodium dendrite growth.

(Invited) Confirmation of Na-O-Li Configuration for P2-Type Cathode Materials

Oxygen-redox-based cathode materials for sodium-ion batteries (SIBs) have attracted considerable attention in recent years owing to their possibility of delivering additional capacity in the high-voltage region. However, they still suffer from not only fast capacity fading but also poor rate capability. Herein, we introduce P2-Na0.75[Li0.15Ni0.15Mn0.7]O2, an oxygen-redox-based layered oxide cathode material for SIBs. The effect of Ni doping on the electrochemical performance was investigated by comparison with Ni-free P2-Na0.67[Li0.22Mn0.78]O2. The Na0.75[Li0.15Ni0.15Mn0.7]O2 delivered a specific capacity of ~160 mAh g-1 in the voltage region of 1.5–4.6 V at 0.1C in Na cells. Combined experiments (galvanostatic cycling, neutron powder diffraction (NPD), X-ray absorption spectroscopy (XANES), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (7Li NMR)) and theoretical studies (density functional theory, DFT calculations) confirmed that Ni substitution not only increases the operating voltage and decreases voltage hysteresis but also improves the cycling stability by reducing Li migration from transition metal (TM) to Na layers. This research demonstrates the effect of Li and Ni co-doping in P2-type layered materials and suggests a new strategy of using Mn-rich cathode materials via oxygen redox with optimization of doping elements for SIBs.

In-situ constructing efficient gel polymer electrolyte with fluoride-rich interface enabling high-capacity, long-cycling sodium metal batteries

Sodium metal batteries (SMBs) are considered feasible candidate for large-scale energy systems. However, complicated reactions between the electrode and electrolyte in liquid electrolyte system lead to poor performance and significant safety issues. Therefore, constructing stable electrode-electrolyte interface is necessary to enhance the comprehensive performance of cells. Utilizing gel polymer electrolytes (GPEs) by in-situ polymerization and moderate additive can effectively address these problems. Herein, a series of fluoroethylene carbonate (FEC) modified GPEs have been successfully prepared by one-step in-situ polymerization, in which trimethylolpropane trimethyl acrylate (TMPTMA) and 1,6-hexanediol diacrylate (HDDA) were used as polymer monomers. As a result, the as-optimized electrolyte, THDP-FEC-2%, exhibited high ionic conductivity (3.77 × 10−3 S cm−1) at 25 °C, high Na+ migration number (0.41), and broad electrochemical window (4.6 V). Encouragingly, the NVP|THDP-FEC-2%|Na cell even exhibited ultra-long cycling stability at high rate (95.31% capacity retention at 5C after 1000 cycles). Such excellent electrochemical performances are attributed to the successful establishment of uniform and dense NaF-rich solid electrolyte interface protection layer. This work is expected to offer interface soft protection layer tuned strategy to construct the ideal interface for high-performance SMBs.

High-throughput sequencing-based Detection of Japanese encephalitis virus and its effect on micro ribonucleic acid

it was to explore the mechanism of Japanese encephalitis virus (JEV) and micro ribonucleic acid (miRNA) under high-throughput sequencing. 20 experimental mice, with good growth status and no disease infection, were selected. The cells used in the experiment included mouse microglial cell line (BV2), mouse neuroblastoma cell line (NA), and mouse brain endothelial cell line (bEnd.3). JEV titration was performed with JEV-infected cells, ribonucleic acid (RNA) in the cells was extracted, and finally the miRNA high-throughput sequencing data was analyzed. Agarose gel electrophoresis showed that the 28S and 18S electrophoresis bands were bright. Among the miRNAs detected in mouse brain tissues, 2986 were down-regulated and 1251 were up-regulated. Among miRNAs detected in NA cells, 4238 the decreasing expression and 2356 were expressed increasingly. In reducing miRNA expression, 1 multiplicity of infection (MOI) of P3 strain infection was more significant than 0.1 MOI. 10 miRNAs with significantly decreasing expression were miR-466d-3p, miR-381–3p, miR-540–3p, miR-466a-3p, miR-467a-3p, miR-574–5p, miR-199a-5p, miR-467a-5p, miR-674–5p, and miR-376b-3p. These were all obviously down-regulated in JEV-infected BV2, NA, and bEnd.3 neurons. High-throughput sequencing of JEV-infected mouse brain tissues and mouse neuronal cells found that JEV infection led to down-regulation of overall miRNA expression in host cells.

Evidence of Zintl Intermediate Phase and Its Impacts on Li and Na Storage Performance of Pb-Based Alloying Anodes

Anode materials based on conversion and alloying reactions are promising to achieve high energy density of advanced sodium-ion batteries (SIBs). While the chemical similarities between sodium and lithium as alkali elements make the benchmarking strategy practical in developing new high-performance anodes, simply borrowing the anode material from one system to the other does not always guarantee success unless it is based on sound understanding of both Li- and Na-reaction mechanisms. In this work, we report the Na storage performance of a Pb-based anode and its fundamental reaction dynamics. In contrast to its excellent electrochemical performances in Li cells (reversible ∼600 mAh/g), the newly developed Pb@PbO–C nanocomposite anode has limited electrochemical Na reaction properties showing moderate capacity and rate performances (∼300 mAh/g at 20 mA/g). Synchrotron-based X-ray diffraction and absorption spectroscopy studies reveal the fundamental differences in the Na and Li reaction mechanism of the Pb-based anode. Unlike Li reaction, the unique Na reaction mechanism involves the formation of a highly ionic NaPb Zintl phase, which comprises tetrahedral Pb4 clusters, as an intermediate phase. The strong covalent character of the Pb4 Zintl clusters adversely affects the electronic conductivity and thus limits the electrochemical performance of the Pb-based anode in Na cells. These findings provide new insights applicable to developing high-performance alloying anode materials.

Metal–Organic Framework Enabling Poly(Vinylidene Fluoride)‐Based Polymer Electrolyte for Dendrite‐Free and Long‐Lifespan Sodium Metal Batteries

Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and, more importantly, cause internal short circuit and lead to thermal runaway and fire. Therefore, sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries (SMBs). Herein, a design concept for the incorporation of metal–organic framework (MOF) in polymer matrix (polyvinylidene fluoride‐hexafluoropropylene) is practiced to prepare a novel gel polymer electrolyte (PH@MOF polymer‐based electrolyte [GPE]) and thus to achieve high‐performance SMBs. The addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na+ but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction. A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm−2 with areal capacity of 5 mA h cm−2 is achieved by symmetric cells based on the resulted GPE while the Na3V2O2(PO4)2F@rGO (NVOPF)|PH@MOF|Na cell also displays impressive specific cycling capacity (113.3 mA h g−1 at 1 C) and rate capability with considerable capacity retention.

Effect of SiO2 microstructure on ionic transport behavior of self-healing composite electrolytes for sodium metal batteries

Batteries matched with flexible intelligent electronic devices are required in the future to supply dense and reliable power security. In addition to energy storage performance, functionalized design of batteries with good mechanical properties and self-healing ability is critical to the development of flexible intelligent electronic devices. The polymer with quadruple hydrogen bonds can give materials the ability to repair mechanical damage and restore the original mechanical properties. The incorporation of inorganic fillers into polymer electrolytes can improve the electrochemical properties and stability of the electrolytes. Optimization of the geometry of inorganic materials could further improve the electrical conductivity of composite electrolytes. In this work, a flexible self-healing polymer electrolyte (Poly (ethylene glycol)-co-ureidopyrimidinone), PEG-UPy) was synthesized. Three different microstructures of SiO2 fillers (solid, mesoporous, and hollow mesoporous) with UPy modified were designed to improve the sodium ion transport performance of the PEG-UPy self-healing polymer electrolyte for sodium ion batteries. The PEG-UPy electrolyte filled with hollow mesoporous SiO2 (PEG-UPy@hSiO2) exhibits an excellent electrochemical performance due to its unique structure among the samples. The PEG-UPy@hSiO2 electrolyte shows the highest ionic conductivity, sodium ion transference number, and appropriate self-healing property. The discharge capacity of NVP/PEG-UPy@hSiO2-NaTFSI (HCPE)/Na cell could reach 110.5 mAh g−1 at 0.1C and the capacity retention rate could reach more than 77.6% after 200 cycles at 60 °C.

Stable Formulations for the Lithium and Sodium Metal Interfaces in Alkali Metal-Oxygen Batteries

The high reactivity of both positive and negative interfacial regions in metal-oxygen (M-O2) batteries leads to a variety of parasitic degradation reactions that reduce reversibility on charge/discharge and can lead to rapid cell failure. To reversibly access the high theoretical specific energies these chemistries promise (3456 and 1602 Wh·kg-1 for Li-O2 and Na-O2, respectively), reducing charging overpotentials and the design of new electrode and electrolyte materials with improved stabilities are key targets. Considering the M|electrolyte interface, where decomposition reactions and dendrite formation generates severe safety concerns as well as reduced cycling stabilities, surface protection of the alkali metal anode by pre-treatment techniques or additive formulation has been among the more successful methodologies.1 In this work, we present a formulation strategy targeting enhanced cycling stabilities of the metal anode in M-O2 cells. Initially demonstrated in the Li-O2 chemistry, we report on an in-depth investigation into the electrochemical performance and the spectroscopic and diffusional properties of ternary ionic liquid (IL)-molecular solvent blend electrolytes.2 By introduction of the IL and exploring a wide formulation range (Figure 1a), we attain significant enhancements in the stability of practically-relevant electrolyte materials that otherwise fail rapidly at alkali metal anodes (Figure 1b), achieving the highest Coulombic efficiencies for Li plating/stripping in this solvent. The optimized formulations consequently displayed enhanced performances in Li-O2 full cells and ex situ characterization of Li surfaces also revealed the suppression of dendrite formation and important changes in the solid electrolyte interphase as a result of modulating solvent reactivity. Using Raman spectroscopy and diffusional analyses, we relate this closely to the local solvation environments involving the reactive solvent component in optimized formulations and, therefore, elucidate critical solvent/Li-salt ratios for improved stability.By understanding key shifts in Raman spectra relating to solvation effects in concentrated Li formulations, and how this modulates cycling performances, we further demonstrate the applicability of this relationship and formulation strategy to the Na-O2 battery chemistry. Therein, the Na metal interface is comparably more reactive and, therefore, presents greater stability challenges, with decomposition reactions in non-optimized formulations more rapidly causing plating and stripping at the anode to fail. However, we demonstrate the plating/stripping of Na (Figure 1c) and cycle lifetime in Na-O2 cells can be hugely improved by applying the above strategy and understandings of critical solvation interactions to equivalent formulations based on Na-salts. Y. Yu, G. Huang, J.-Z. Wang, K. Li, J.-L. Ma, and X.-B. Zhang, Adv. Mater. (Weinheim, Ger.), 32 (38), 2004157 (2020). A. R. Neale, R. Sharpe, S. R. Yeandel, C.-H. Yen, K. V. Luzyanin, P. Goddard, E. A. Petrucco, and L. J. Hardwick, Adv. Funct. Mater., 31 (27), 2010627 (2021). Figure 1. (a) Ternary plot highlighting the changes in stability of Li/Na metal anode cycling as a function of the studied formulation ranges and example voltage profiles of symmetric (b) Li|Li cells and (c) Na|Na cells with non-optimized (navy/purple) and optimized (orange) electrolyte formulations. Figure 1

High-Voltage, Highly Reversible Sodium Batteries Enabled by Fluorine-Rich Electrode/Electrolyte Interphases.

High energy density and long-term cycling stability are crucial factors for the commercialization of sodium batteries in large scale. In this regard, cathode materials that can operate at high voltage have attracted great interest owing to their high energy density. However, traditional electrolytes cannot be used in high-voltage sodium batteries due to their limited oxidative stability. Therefore, there is a great challenge to develop appropriate electrolytes for high-voltage cathode materials. Herein, a diluted fluoroethylene carbonate (FEC)-based electrolyte (1 m NaPF6 in FEC/DMC = 2/8 by volume) is designed for Na4 Co3 (PO4 )2 P2 O7 (NCPP) cathode with a high operation voltage of 4.7V to achieve superior electrochemical performance with a capacity retention of 90.10% after 500 cycles at 0.5C and capacity retention of 89.99% after 1000 cycles at 1C. The excellent electrochemical performance of the NCPP||Na cells can be attributed to the formation of inorganic and robust NaF-rich cathode electrolyte interphase and F-rich solid electrolyte interface on high voltage NCPP cathode and Na metal anode, respectively. This work points out a very promising strategy to develop high-voltage sodium batteries toward practical applications.