Mitigating Concentration Polarization through Acid-Base Interaction Effects for Long-Cycling Lithium Metal Anodes.

Lithium (Li) metal has attracted great attention as a promising high-capacity anode material for next-generation high-energy-density rechargeable batteries. Nonuniform Li+ transport and uneven Li plating/stripping behavior are two key factors that deteriorate the electrochemical performance. In this work, we propose an interphase acid-base interaction effect that could regulate Li plating/stripping behavior and stabilize the Li metal anode. ZSM-5, a class of zeolites with ordered nanochannels and abundant acid sites, was employed as a functional interface layer to facilitate Li+ transport and mitigate the cell concentration polarization. As a demonstration, a pouch cell with a high-areal-capacity LiNi0.95Co0.02Mn0.03O2 cathode (3.7 mAh cm-2) and a ZSM-5 modified thin lithium anode (50 µm) delivered impressive electrochemical performance, showing 92% capacity retention in 100 cycles (375.7 mAh). This work reveals the effect of acid-base interaction on regulating lithium plating/stripping behaviors, which could be extended to developing other high-performance alkali metal anodes.

Manipulating Redox Kinetics of Sulfur Species Using Mott-Schottky Electrocatalysts for Advanced Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries suffer from sluggish sulfur redox reactions under high-sulfur-loading and lean-electrolyte conditions. Herein, a typical Co@NC heterostructure composed of Co nanoparticles and a semiconductive N-doped carbon matrix is designed as a model Mott-Schottky catalyst to exert the electrocatalytic effect on sulfur electrochemistry. Theoretical and experimental results reveal the redistribution of charge and a built-in electric field at the Co@NC heterointerface, which are critical to lowering the energy barrier of polysulfide reduction and Li2S oxidation in the discharge and charge process, respectively. With Co@NC Mott-Schottky catalysts, the Li-S batteries display an ultrahigh capacity retention of 92.1% and a system-level gravimetric energy density of 307.8 Wh kg-1 under high S loading (10.73 mg cm-2) and lean electrolyte (E/S = 5.9 µL mgsulfur-1) conditions. The proposed Mott-Schottky heterostructure not only deepens the understanding of the electrocatalytic effect in Li-S chemistry but also inspires a rational catalyst design for advanced high-energy-density batteries.

A Replacement Reaction Enabled Interdigitated Metal/Solid Electrolyte Architecture for Battery Cycling at 20 mA cm-2 and 20 mAh cm-2.

Metal anodes represent as a prime choice for the coming generation rechargeable batteries with high energy density. However, daunting challenges including electrode volume variation and inevitable side reactions preclude them from becoming a viable technology. Here, a facile replacement reaction was employed to fabricate a three-dimensional (3D) interdigitated metal/solid electrolyte composite electrode, which not only provides a stable host structure for buffering the volume change within the composite but also prevents side reactions by avoiding the direct contact between active metal and liquid electrolyte. As a proof-of-concept demonstration, a 3D interdigitated zinc (Zn) metal/solid electrolyte architecture was fabricated via a galvanic replacement reaction between Zn metal foil and indium (In) chloride solution followed by electrochemical activation, featuring the interdigitation between metallic Zn and amorphous indium hydroxide sulfate (IHS) with high Zn2+ conductivity (56.9 ± 1.8 mS cm-1), large Zn2+ transference number (0.55), and high electronic resistivity [(2.08 ± 0.01) × 103 Ω cm]. The as-designed Zn/IHS electrode sustained stable electrochemical Zn plating/stripping over 700 cycles with a record-low overpotential of 8 mV at 1 mA cm-2 and 0.5 mAh cm-2. More impressively, it displayed cycle-stable performance with low overpotential of 10 mV under ultrahigh current density and areal capacity (20 mA cm-2, 20 mAh cm-2), which outperformed all the reported Zn metal electrodes in mild aqueous electrolyte. The fabrication of interdigitated metal/solid electrolyte was generalized to other metal pairs, including Zn/Sn and Zn/Co, which provide inspiration for next-generation Zn metal batteries with high energy density and reversibility.

Metal/LiF/Li2O Nanocomposite for Battery Cathode Prelithiation: Trade-off between Capacity and Stability.

Lithium-ion batteries (LIBs) are currently dominating the portable electronics market and supplying power for electric vehicles and grid-level storage. However, lithium loss in the formation cycle at the anode side reduces the energy density of state-of-the-art LIBs with carbon anode materials. This situation will be even more severe for future LIBs using high-capacity Si-based anode materials. In this study, a transition metal-based nanocomposite with built-in lithium source was synthesized, featuring Fe nanodomains with a size of ∼5 nm uniformly dispersed in a hybrid Li2O and LiF matrix with intimate contact between them. The Fe/LiF/Li2O nanocomposite released a high Li-ion capacity of 550 mA h/g based on a multielectron inverse conversion reaction during the first-cycle charge process and exhibited better ambient stability than the counterpart with a pure Li2O matrix and also a lower lithium-extraction voltage and faster reaction kinetics than the counterpart with a pure LiF matrix. Serving as an additive to various cathodes (e.g., LiCoO2, LiFePO4, and LiNi1-x-yCoxMnyO2), the Fe/LiF/Li2O nanocomposite showed excellent lithium compensation effect. Using 4.8 wt % Fe/LiF/Li2O additive based on the total mass of the electrodes, a LiNi0.8Co0.1Mn0.1O2|SiO-graphite full cell with a high cathode mass loading of 20 mg/cm2 exhibited a high reversible capacity of 2.9 mA h/cm2 at 0.5 C after 100 cycles which is a 15% increase in comparison to the counterpart without the prelithiation additive. After the Fe/LiF/Li2O nanocomposite was immersed into the electrolyte and rested for 72 h, the content of iron metal in the electrolyte was negligible, indicating that this prelithiation additive was stable in the electrolyte and would not cause any side reactions, such as the shuttle of iron ions during cycling. The high "donor" Li-ion capacity, good ambient stability, and its compatibility with existing cathode materials and battery fabrication processes make the Fe/LiF/Li2O nanocomposite a promising cathode prelithiation additive to offset the initial lithium loss and improve the energy density of LIBs.

Stable interphase chemistry of textured Zn anode for rechargeable aqueous batteries.

Despite the advances of aqueous zinc (Zn) batteries as sustainable energy storage systems, their practical application remains challenging due to the issues of spontaneous corrosion and dendritic deposits at the Zn metal anode. In this work, conformal growth of zinc hydroxide sulfate (ZHS) with dominating (001) facet was realized on (002) plane-dominated Zn metal foil fabricated through a facile thermal annealing process. The ZHS possessed high Zn2+ conductivity (16.9 mS cm-1) and low electronic conductivity (1.28 × 104 Ω cm), and acted as a heterogeneous and robust solid electrolyte interface (SEI) layer on metallic Zn electrode, which regulated the electrochemical Zn plating behavior and suppressed side reactions simultaneously. Moreover, low self-diffusion barrier along the (002) plane promoted the 2D diffusion and horizontal electrochemical plating of metallic Zn for (002)-textured Zn electrode. Consequently, the as-achieved Zn electrode exhibited remarkable cycling stability over 7000 cycles at 2 mA cm-2 and 0.5 mAh cm-2 with a low overpotential of 25 mV in symmetric cells. Pairing with a MnO2 cathode, the as-achieved Zn electrode achieved stable cell cycling with 92.7% capacity retention after 1000 cycles at 10 C with a remarkable average Coulombic efficiency of 99.9%.

Addressing the Low Solubility of a Solid Electrolyte Interphase Stabilizer in an Electrolyte by Composite Battery Anode Design.

Metallic sodium (Na) has been regarded as one of the most attractive anodes for Na-based rechargeable batteries due to its high specific capacity, low working potential, and high natural abundance. However, several important issues hinder the practical application of the metallic Na anode, including its high reactivity with electrolytes, uncontrolled dendrite growth, and poor processability. Metal nitrates are common electrolyte additives used to stabilize the solid electrolyte interphase (SEI) on Na anodes, though they typically suffer from poor solubility in electrolyte solvents. To address these issues, a Na/NaNO3 composite foil electrode was fabricated through a mechanical kneading approach, which featured uniform embedment of NaNO3 in a metallic Na matrix. During the battery cycling, NaNO3 was reduced by metallic Na sustainably, which addressed the issue of low solubility of an SEI stabilizer. Due to the supplemental effect of NaNO3, a stable SEI with NaNxOy and Na3N species was produced, which allowed fast ion transport. As a result, stable electrochemical performance for 600 h was achieved for Na/NaNO3||Na/NaNO3 symmetric cells at a current density of 0.5 mA cm-2 and an areal capacity of 0.5 mAh cm-2. A Na/NaNO3||Na3V2(PO4)2O2F cell with active metallic Na of ∼5 mAh cm-2 at the anode showed stable cycling for 180 cycles. In contrast, a Na||Na3V2(PO4)2O2F cell only displayed less than 80 cycles under the same conditions. Moreover, the processability of the Na/NaNO3 composite foil was also significantly improved due to the introduction of NaNO3, in contrast to the soft and sticky pure metallic Na. Mechanical kneading of soft alkali metals and their corresponding nitrates provides a new strategy for the utilization of anode stabilizers (besides direct addition into electrolytes) to improve their electrochemical performance.

Aquatic microbial community is partially functionally redundant: Insights from an in situ reciprocal transplant experiment.

Microbial communities are considered to be functionally redundant, but few studies have tested this hypothesis empirically. In this study, we performed an in situ reciprocal transplant experiment on the surface and bottom waters of two lakes (Tsuei-Feng (T) and Yuan-Yang (Y)) with disparate trophic states and tracked changes in their microbial community composition and functions for 6 weeks using high-throughput sequencing and functional approaches. T lake's surface (Ts) and bottom (Tb) water active bacterial community (16S rRNA gene-transcript) was dominated by Actinobacteria, Bacteroidia, and Cyanobacteria, whereas Y lake's surface (Ys) and bottom (Yb) water had Gammaproteobacteria, Alphaproteobacteria, and Bacteroidia as the dominant classes. The community composition was resistant to changes in environmental conditions following the reciprocal transplant, but their functions tended to become similar to the incubating lakes' functional profiles. A significant linear positive relationship was observed between the microbial community and functional attributes (surface: R2 = 0.5065, p < 0.0001; bottom: R2 = 0.4592, p < 0.0001), though with varying scales of similarity (1-Bray Curtis distance), suggesting partial functional redundancy. Also, the entropy-based L-divergence measure identified high divergence in community composition (surface: 1.21 ± 0.54; bottom: 1.17 ± 0.51), and relatively low divergence in functional attributes (surface: 0.04 ± 0.01; bottom: 0.04 ± 0.01) in the two lakes' surface and bottom waters, providing further support for the presence of partial functional redundancy. This study enriches our understanding of community functional relationships and establishes the presence of partial functional redundancy in freshwater ecosystems.

Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode.

To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. We demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30 mA cm-2 and 5 mAh cm-2 with a very low overpotential of 20 mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6 C (6.6 mA cm-2), a 1.0 mAh cm-2 LiNi0.6Co0.2Mn0.2O2 electrode maintains a substantial 74% of its capacity by pairing with such anode.

A Lithium Metal Anode Surviving Battery Cycling Above 200 °C.

Lithium (Li) metal electrode cannot endure elevated temperature (e.g., >200 °C) with the regular battery configuration due to its low melting point (180.5 °C) and high reactivity, which restricts its application in high-temperature Li metal batteries for energy storage and causes safety concerns for regular ambient-temperature Li metal batteries. Herein, this work reports a Li5 B4 /Li composite featuring a 3D Li5 B4 fibrillar framework filled with metallic Li, which maintains its initial structure at 325 °C in Ar atmosphere without leakage of the liquid Li. The capillary force caused by the porous structure of the Li4 B5 fibrillar framework, together with its lithiophilic surface, restricts the leakage of liquid metallic Li and enables good thermal tolerance of the Li5 B4 /Li composite. Thus, it can be facilely operated for rechargeable high-temperature Li metal batteries. Li5 B4 /Li electrodes are coupled with a garnet-type ceramic electrolyte (Li6.5 La3 Zr0.5 Ta1.5 O12 ) to fabricate symmetric cells, which exhibit stable Li stripping/plating behaviors with low overpotential of ≈6 mV at 200 °C using a regular sandwich-type cell configuration. This work affords new insights into realizing a stable Li metal anode for high-temperature Li metal batteries with a simple battery configuration and high safety, which is different from traditional molten-salt Li metal batteries using a pristine metallic Li anode.

Enhanced Chemical Immobilization and Catalytic Conversion of Polysulfide Intermediates Using Metallic Mo Nanoclusters for High-Performance Li-S Batteries.

Rechargeable lithium-sulfur batteries have attracted tremendous scientific attention owing to their high energy density. However, their practical application is greatly hindered by the notorious shuttling of soluble lithium polysulfide (LPS) intermediates with sluggish redox reactions and uncontrolled precipitation behavior. Herein, we report a semiliquid cathode composed of an active LPS solution/carbon nanofiber (CNF) composite layer, capped with a carbon nanotube (CNT) thin film decorated with metallic Mo nanoclusters that regulate the electrochemical redox reactions of LPS. The trace amount (0.05 mg cm-2) of metallic Mo on the CNT film provides sufficient capturing centers for the chemical immobilization of LPS. Together with physical blocking of LPS by the compact CNT film, free diffusion of LPS is significantly restrained and the self-discharge behavior of the Li-S cell is thus effectively suppressed. Importantly, the metallic Mo nanoclusters enable fast catalytic conversion of LPS and regular deposition of lithium sulfide. As a result, the engineered cathode exhibits a high active sulfur utilization (1401 mAh g-1 at 0.1 C), stable cycling (500 cycles at 1 C with 0.06% decay per cycle), high rate performance (694 mAh g-1 at 5 C), and low self-discharge rate (3% after 72 h of rest). Moreover, a high reversible areal capacity of 4.75 mAh cm-2 is maintained after 100 cycles at 0.2 C for a cathode with a high sulfur loading of 7.64 mg cm-2. This work provides significant insight into the structural and materials design of an advanced sulfur-based cathode that effectively regulates the electrochemical reactions of sulfur species in high-energy Li-S batteries.

Prevalence of enteroviruses in hot spring recreation areas of Taiwan.

Enteroviruses can be introduced into the water environment as a result of human activity. Contaminations within hot tubs, spas and public baths are also possible. We investigated the distribution of enteroviruses at six hot spring recreation areas throughout Taiwan. Spring water was collected from 34 sites and enteroviruses were detected in 13 (38.2%). The most frequently detected was coxsackievirus A2, followed by echovirus 11. Enterovirus 71 (EV 71) and porcine enterovirus 9 were detected once. Water quality indicators were not statistically associated with the occurrence of enteroviruses, although the enterovirus-positive samples were positive for a greater number of microbiological indicators and showed a link to pH and water temperature. The results confirm the ubiquity of enteroviruses in Taiwan spring recreation areas. Coxsackievirus A2, echovirus 11 and EV 71, the enteroviruses responsible for disease outbreaks identified at these sites, should be considered a potential public health threat in spring recreation areas of Taiwan.

Seasonal Distribution and Genotyping of Antibiotic Resistant Strains of ListeriaInnocua Isolated from A River Basin Categorized by ERIC-PCR.

Listeria innocua retains many conserved homologous domains with Listeria monocytogenes, which is a food-borne and water-borne diarrhea-causing bacterium. Studies of antimicrobial resistance in L. innocua showed that this microbe is more prone to acquire resistance than other bacteria in the genus Listeria. However, little is known about the seasonal population distribution and antimicrobial resistance patterns of L. innocua in natural water environments. The aims of the study were: (1) to investigate the occurrence of L. innocua isolates in a subtropical watershed and reconstruct the population structure and (2) to analyze the antibacterial resistance patterns of the identified L. innocua isolates according to ERIC type. A total of 288 water samples was collected from the Puzi River basin (23°28' N, 120°13' E) between March 2014 and March 2015, and 36 L. innocua isolates were recovered from 15 positive water samples. With regard to seasonal variation, L. innocua was only detected in the spring and summer. Eighteen enterobacterial repetitive intergenic consensus (ERIC)-PCR types were identified, and two genogroups with four subgroups were reconstructed in a minimum spanning tree. Isolates from different sampling areas that were located near each other were genetically different. All L. innocua isolates (including 41.7% of the multidrug-resistant (MDR) isolates) were resistant to oxacillin and showed high minimum inhibitory concentrations of tetracycline. These findings demonstrate the seasonal variations and differing geographical distributions of L. innocua in this subtropical water environment, as well as the existence of strong population structures and MDR and antimicrobial resistance patterns. Phylogenetic analysis based on ERIC-type showed that the Cluster A isolates were resistant to more antibiotics, and two types, ERIC8 and ERIC15 were multidrug resistant. The more commonly detected types, such as ERIC1 and ERIC12, were also more likely to be resistant to two or more antibiotics. Close monitoring of drug resistance in environmental L. innocua is warranted due to its potential for transferring antimicrobial resistance determinants to pathogenic Listeria.

Bacterial Community in Water and Air of Two Sub-Alpine Lakes in Taiwan.

Very few studies have attempted to profile the microbial communities in the air above freshwater bodies, such as lakes, even though freshwater sources are an important part of aquatic ecosystems and airborne bacteria are the most dispersible microorganisms on earth. In the present study, we investigated microbial communities in the waters of two high mountain sub-alpine montane lakes-located 21 km apart and with disparate trophic characteristics-and the air above them. Although bacteria in the lakes had locational differences, their community compositions remained constant over time. However, airborne bacterial communities were diverse and displayed spatial and temporal variance. Proteobacteria, Actinobacteria, Bacteroidetes, and Cyanobacteria were dominant in both lakes, with different relative abundances between lakes, and Parcubacteria (OD1) was dominant in air samples for all sampling times, except two. We also identified certain shared taxa between lake water and the air above it. The results obtained on these communities in the present study provide putative candidates to study how airborne communities shape lake water bacterial compositions and vice versa.

Genetic diversity of epidemic enterovirus 71 strains recovered from clinical and environmental samples in Taiwan.

Most enteroviruses excreted in human feces and urine are present in environmental water. In order to clarify the infection route of enterovirus, the detection of viruses in both clinical and environmental samples may contribute to understanding the mode of transmission of strains responsible for human infection. Thus, 21 epidemic enterovirus 71 strains from environmental water or stool samples were collected from HFMD children during 2005. Enterovirus genomic RNA was first amplified directly from clinical and environmental samples and then characterized by DNA sequencing and phylogenetic analysis. Results showed that these clinical strains share similar sequence identity (86.4-86.8%) to prototype BrCr based on the 5'-nontranslated region (NTR). However, environmental strains, except HME 77, share similar sequence identity (86.2-87.2%) to prototype BrCr. HME 77 showed higher sequence identity (90.1%). Results from phylogenetic analysis revealed that five environmental isolates were clustered as genogroup 3, which was closely related to a Taiwan outbreak in 1998 (AY055133). HME 77 was more closely related to a China epidemic isolate (AY895144), which belonged to genogroup 4. In contrast, all strains from clinical samples tested belonged to genogroup 3, which clustered with AY055133. In conclusion, there are two major epidemic clones (genogroups 3 and 4) prevalent in Taiwan since 2004 either in water or clinical patients.

Evaluation of enterovirus recovery in surface water by different adsorption and elution procedures.

The performance of six concentration method combinations and two quantitative analysis techniques were evaluated in terms of enterovirus recovery efficiencies by adjusting the pH and salt concentration of water samples. Of the six concentration method combinations, adsorption on nitrocellulose membranes followed by an acid rinse elution consistently gave the highest recovery efficiencies. In theory, an electropositive membrane should be the most appropriate technique for adsorption of electronegative viruses in pure water. However, it displayed the greatest loss in natural waters. For adsorption and elution procedures, both the electronegative membrane, accompanied by an acid rinse step, and the electropositive membrane, accompanied by a glycine rinse step, provided higher recovery efficiencies. MPN-RT-PCR, a statistically quantitative analysis method, performed more efficiently, in economic terms, but had a similar enterovirus recovery trend to real-time RT-PCR, which is the authoritative quantitative analysis method for nucleic acid.

Molecular characteristics of clinical methicillin-resistant Staphylococcus pseudintermedius harboring arginine catabolic mobile element (ACME) from dogs and cats.

This study aimed to investigate the presence of arginine catabolic mobile element (ACME) and its associated molecular characteristics in methicillin-resistant Staphylococcus pseudintermedius (MRSP). Among the 72 S. pseudintermedius recovered from various infection sites of dogs and cats, 52 (72.2%) were MRSP. ACME-arcA was detected commonly (69.2%) in these MRSP isolates, and was more frequently detected in those from the skin than from other body sites (P=0.047). There was a wide genetic diversity among the ACME-arcA-positive MRSP isolates, which comprised three SCCmec types (II-III, III and V) and 15 dru types with two predominant clusters (9a and 11a). Most MRSP isolates were multidrug-resistant. Since S. pseudintermedius could serve as a reservoir of ACME, further research on this putative virulence factor is recommended.

Legionella prevalence in hot spring recreation areas of Taiwan.

Legionella is a bacterium ubiquitous to aquatic environments. Within the genus a few species are recognized as opportunistic potential human pathogens, especially the species Legionella pneumophila, which causes pneumonia legionellosis. Outbreaks of legionellosis are frequently reported by hotel guests and hospital patients, and are spread through inhaled aerosols of contaminated institutional water systems. Contaminations in hot tubs, spas and public baths are also possible. As a result, in this study, we investigated the distribution of Legionella at seven hot spring recreational areas throughout Taiwan. We gathered data on factors potentially associated with the pathogen's distribution, including environment, facility operation, and physical and microbiological water quality parameters. Spring water was collected from 91 sites and Legionella was detected in 21 (23%). The most frequently detected was L. pneumophila, followed by uncultured Legionella species, Legionella-like amoebal pathogen. Five species, L. bozemanii, L. dumoffi, L. feelei, L. lyticum and L. oakridgenesis, were all detected once. Legionella species were found in water temperatures ranging from 22 to 50 degrees C. Optimal pH appeared to be between 5.0 and 9.0. The prevalence of Legionella also coincided with the prevalence of indicator microorganisms. Legionella detection was not proportional to the frequency of cleaning. Results of this survey confirm the ubiquity of Legionella in Taiwan spring recreation areas. L. pneumophila, the organism responsible for the majority of legionellosis outbreaks, should be considered a potential public health threat in spa areas of Taiwan.

Using the flow cytometry to quantify the Giardia cysts and Cryptosporidium oocysts in water samples.

The flow cytometry (FC) has been used to detect Giardia cysts and Cryptosporidium oocysts quantitatively and instantaneously in this study. The experimental results showed that FC is potential to become a more precise method for the detection of Giardia and Cryptosporidium in water. This study also evaluated the staining efficiencies for three commercial antibodies. After staining Cryptosporidium oocysts with direct immunofluorescent antibodies in water samples, two populations were detected in the scatter-plots (FL1 versus SSC) of the FC. The Cryptosporidium oocysts and Giardia cysts are significantly separated from other particles while stained with direct immunofluorescent antibodies produced by Meridian Diagnostics and Waterborne Inc.