A comparative analysis of alternative splicing patterns in Atlantic salmon (Salmo salar) in response to Moritella viscosa and sea lice (Lepeophtheirus salmonis) infection.

Moritella viscosa (M. viscosa) and sea lice (Lepeophtheirus salmonis) are severe pathogens that primarily infect the skin of Atlantic salmon (Salmo salar), which cause significant economic losses in the farming industry. However, the pathogenesis and molecular mechanisms underlying the host's immune defence at the post-transcriptional level remain unclear. Alternative splicing (AS) is an evolutionarily conserved post-transcriptional mechanism that can greatly increase the richness of the transcriptome and proteome. In this study, transcriptomic data derived from skin tissues of Atlantic salmon after M. viscosa and sea lice infections were used to examine the AS profiles and their differential expression patterns. In total, we identified 33,044 AS events (involving 13,718 genes) in the control (CON) group, 35,147 AS events (involving 14,340 genes) in the M. viscosa infection (MV) group, and 30,364 AS events (involving 13,142 genes) in the sea lice infection (LC) group, respectively. Among the five types of AS identified in our study (i.e., SE, A5SS, A3SS, MXE, and RI), SE was the most prevalent type in all three groups (i.e., CON, MV, and LC groups). Decreased percent-spliced-in (PSI) levels were observed in SE events under both MV- and LC-infected conditions, suggesting that MV or LC infection elevated exon-skipping isoforms and promoted the selection of shorter transcripts in numerous DAS genes. In addition, most of the differential AS genes were found to be associated with pathways related to mRNA regulation, epithelial or muscle development, and immune response. These findings provide novel insights into the role of AS in host-pathogen interactions and represent the first comparative analysis of AS in response to bacterial and parasitic infections in fish.

Chromosome level genome assembly and transcriptome analysis of E11 cells infected by tilapia lake virus.

The E11 cell line, derived from striped snakehead fish (Channa striata), possesses a distinctive feature: it is persistently infected with a C-type retrovirus. Notably, it exhibits high permissiveness to piscine nodavirus and the emerging tilapia lake virus (TiLV). Despite its popularity in TiLV research, the absence of genome assembly for the E11 cell line and Channa striata has constrained research on host-virus interactions. This study aimed to fill this gap by sequencing, assembling, and annotating the E11 cell line genome. Our efforts yielded a 600.5 Mb genome including 24 chromosomes with a BUSCO score of 98.8%. In addition, the complete proviral DNA sequence of snakehead retrovirus (SnRV) was identified in the E11 cell genome. Comparative genomic analysis between the E11 cell line and another snakehead species Channa argus revealed the loss of many immune-related gene families in the E11 cell genome, indicating a compromised immune response. We also conducted transcriptome analysis of mock- and TiLV-infected E11 cells, unveiling new perspectives on virus-virus and host-virus interactions. The TiLV infection suppressed the high expression of SnRV in E11 cells, and activated some other endogenous retroviruses. The protein-coding gene comparison revealed a pronounced up-regulation of genes involved in immune response, alongside a down-regulation of genes associated with specific metabolic processes. In summary, the genome assembly and annotation of the E11 cell line provide valuable resources to understand the SnRV and facilitate further studies on nodavirus and TiLV. The RNA-seq profiles shed light on the cellular mechanisms employed by fish cells in response to viral challenges, potentially guiding the development of therapeutic strategies against TiLV in aquaculture. This study also provides the first insights into the viral transcriptome profiles of endogenous SnRV and evading TiLV, enhancing our understanding of host-virus interactions in fish.

Diagnostic performance evaluation of urine HIV-1 antibody rapid test kits in a real-life routine care setting in China.

OBJECTIVES: To evaluate the diagnostic performance of urine HIV antibody rapid test kits in screening diverse populations and to analyse subjects' willingness regarding reagent types, purchase channels, acceptable prices, and self-testing. DESIGNS: Diagnostic accuracy studies PARTICIPANTS: A total of 2606 valid and eligible samples were collected in the study, including 202 samples from female sex workers (FSWs), 304 persons with injection drug use (IDU), 1000 pregnant women (PW), 100 subjects undergoing voluntary HIV counselling and testing (VCT) and 1000 students in higher education schools or colleges (STUs). Subjects should simultaneously meet the following inclusion criteria: (1) being at least 18 years old and in full civil capacity, (2) signing an informed consent form and (3) providing truthful identifying information to ensure that the subjects and their samples are unique. RESULTS: The sensitivity, specificity and area under the curve (AUC) of the urine HIV-1 antibody rapid test kits were 92.16%, 99.92% and 0.960 (95% CI: 0.952 to 0.968, p<0.001), respectively, among 2606 samples collected during on-site screenings. The kits showed good diagnostic performance in persons with IDU (AUC, 1.000; 95% CI, 1.000 to 1.000, p<0.001), PW (AUC, 0.999; 95% CI, 0.999 to 1.000, p<0.001) and FSWs (AUC, 1.000; 95% CI, 1.000 to 1.000, p<0.001). The AUC of the urine reagent kits in subjects undergoing VCT was 0.941 (95% CI: 0.876 to 0.978, p<0.001). The 'acceptable price' had the greatest influence on STUs (Pi=1.000) and PW (Pi=1.000), the 'purchase channel' had the greatest influence on subjects undergoing VCT (Pi=1.000) and persons with IDU (Pi=1.000) and the 'reagent types' had the greatest influence on FSWs (Pi=1.000). CONCLUSIONS: The rapid urine test kits showed good diagnostic validity in practical applications, despite a few cases involving misdiagnosis and underdiagnosis.

Gut dysbiosis induced by florfenicol increases susceptibility to Aeromonas hydrophila infection in Zebrafish Danio rerio after the recommended withdrawal period.

OBJECTIVE: Florfenicol (FFC) is a broad-spectrum antibiotic approved by the U.S. Food and Drug Administration to treat both systemic and external bacterial infections in food fish. The objective of this study was to evaluate the effect of FFC-medicated feed on the gut microbiota of Zebrafish Danio danio to determine (1) if the therapeutic dose of FFC-medicated feed induces dysbiosis and (2) if fish with altered gut microbiota were more susceptible to subsequent infection by the common opportunistic fish pathogen Aeromonas hydrophila. METHODS: Zebrafish that were treated with regular and FFC-medicated feeds were artificially challenged with A. hydrophila at the end of the recommended 15-day antibiotic withdrawal period. The gut microbiota of the Zebrafish at different stages was analyzed using 16S ribosomal RNA gene sequencing. RESULT: Our results found that FFC-medicated feed induced disruption of the gut microbiota. Dysbiosis was observed in all treated groups, with a significant increase in bacterial diversity, and was characterized by a remarkable bloom of Proteobacteria and a drastic decline of Mycoplasma and Cetobacterium in treated animals but without noticeable clinical signs or mortalities. In addition, the increase of Proteobacteria was not significantly reduced after the recommended 15-day withdrawal period, and the Zebrafish treated with FFC-medicated feed exhibited a significantly higher mortality rate when they were subsequently challenged with A. hydrophila compared to the control (regular feed) groups. Interestingly, the most dramatic changes in the gut microbiome composition occurred at the transition time between the late stage of the medicated treatment and the beginning of the withdrawal period instead of the time during the Aeromonas infection. CONCLUSION: The administration of FFC-medicated feed at the recommended dose induced gut dysbiosis in Zebrafish, and fish did not recover to the baseline after the recommended withdrawal period. Our findings suggest that the use of antibiotics in fish elicits a response similar to those previously described in mammals and possibly makes the host more susceptible to subsequent infections of opportunistic pathogens. This study using a controlled model system suggests that antibiotics in aquaculture may have long-term effects on the general well-being of the fish.

Transcriptome analysis revealed immune responses in the kidney of Atlantic salmon (Salmo salar) co-infected with sea lice (Lepeophtheirus salmonis) and infectious salmon anemia virus.

Sea lice (Lepeophtheirus salmonis) and infectious salmon anemia virus (ISAv) are two of the most important pathogens in Atlantic salmon (Salmo salar) farming and typically cause substantial economic losses to the industry. However, the immune interactions between hosts and these pathogens are still unclear, especially in the scenario of co-infection. In this study, we artificially infected Atlantic salmon with sea lice and ISAv, and investigated the gene expression patterns of Atlantic salmon head kidneys in response to both lice only and co-infection with lice and ISAv by transcriptomic analysis. The challenge experiment indicated that co-infection resulted in a cumulative mortality rate of 47.8 %, while no mortality was observed in the lice alone infection. We identified 240 differentially expressed genes (DEGs) under the lice alone infection, of which 185 were down-regulated and 55 were up-regulated, while a total of 994 DEGs were identified in the co-infection, of which 206 were down-regulated and 788 were significantly up-regulated. The pathway enrichment analysis revealed that single-infection significantly suppressed the innate immune system (e.g., the complement system), whereas co-infection induced a strong immune response, leading to the activation of immune-related signaling pathways such as Toll-like receptors and NOD-like receptors pathways, as well as significant upregulation of genes related to the activation of interferon and MH class I protein complex. Our results provide the first global transcriptomic study of gene expression in the Atlantic salmon head kidney in response to co-infection with sea lice and ISAv, and provided the baseline knowledge for understanding the immune responses during co-infection.

Ammonia nitrogen stress damages the intestinal mucosal barrier of yellow catfish (Pelteobagrus fulvidraco) and induces intestinal inflammation.

Nitrogen from ammonia is one of the most common pollutants toxics to aquatic species in aquatic environment. The intestinal mucosa is one of the key mucosal defenses of aquatic species, and the accumulation of ammonia nitrogen in water environment will cause irreversible damage to intestinal function. In this study, histology, immunohistochemistry, ultrastructural pathology, enzyme activity analysis and qRT-PCR were performed to reveal the toxic effect of ammonia nitrogen stress on the intestine of Pelteobagrus fulvidraco. According to histological findings, ammonia nitrogen stress caused structural damage to the intestine and reduced the number of mucous cells. Enzyme activity analysis revealed that the activity of bactericidal substances (Lysozyme, alkaline phosphatase, and ACP) had decreased. The ultrastructure revealed sparse and shortened microvilli as well as badly degraded tight junctions. Immunohistochemistry for ZO-1 demonstrated an impaired intestinal mucosal barrier. Furthermore, qRT-PCR revealed that tight junction related genes (ZO-1, Occludin, Claudin-1) were downregulated, while the pore-forming protein Claudin-2 was upregulated. Furthermore, as ammonia nitrogen concentration grew, so did the positive signal of Zap-70 (T/NK cell) and the expression of inflammation-related genes (TNF, IL-1ß, IL-8, IL-10). In light of the above findings, we conclude that ammonia nitrogen stress damages intestinal mucosal barrier of Pelteobagrus fulvidraco and induces intestinal inflammation.

Near Full-Length Genomic Characterization of Two Novel HIV Type 1 Second-Generation Recombinant Forms (CRF01_AE/CRF07_BC) from Guangxi, China.

CRF01_AE and CRF07_BC are the two predominant HIV-1 subtypes currently circulating in China. We identified here a novel CCR5-tropic HIV-1 second-generation recombinant form virus found in two individuals, (GX19017 and GX19032), which were isolated from two HIV-1-positive people in Guangxi, southwest China. Phylogenic analyses indicated that these two sequences were all composed of two well-established circulating recombinant forms (CRFs) CRF07_BC and CRF01_AE, with four recombinant breakpoints observed in the pol, vpu/env, and env gene regions, respectively. The recombinant CRF01_AE region was clustered with the previously described CRF01_AE subcluster 2 lineage, which was characterized by the susceptibility to phenotypic transfer. The genome structure is significantly different from other previously reported CRFs and unique recombination forms. The emergence of a series of novel recombinant strains is indicative of the burgeoning complexity of the HIV-1 epidemic among the sexually transmitted population. Meanwhile, it may furnish significant insights into the dynamics and intricacy of the HIV-1 epidemic in China.

Reducing volume expansion in micro silicon anodes via aramid nanofibers for stable lithium-ion batteries.

The aramid nanofibers form networks on micro silicon particles (ANF-SMPs) by cryofixation and acid-induced protonation, whose zongzi-like wrapping structure reduces volume expansion during (de)lithiation. The obtained ANF-SMP electrode achieves a high capacity retention of 90.7% after 100 cycles at 0.5C, which maps a promising future for anodes with a long lifespan.

Glutamate levels in the ventromedial prefrontal cortex and resting-state functional connectivity within reward circuits in alcohol-dependent patients.

Great progress has been made in understanding the neural mechanisms associated with alcohol-dependent (AD) patients. However, the interactions within the reward circuits of the patients need further exploration. Glutamatergic projections from the prefrontal cortex to some brain regions are present in the reward circuit. However, little is known about the potential implications of glutamate levels in the prefrontal cortex on abnormal interactions within reward circuits in AD patients. To determine the potential roles of reward circuits in drinking, we investigated differences in resting-state functional connectivity (RSFC) and multivariate Granger causality analysis between 20 AD patients and 20 healthy controls (HC). The neuroimaging findings were then correlated with clinical variables (alcohol use disorder identification test). The ventromedial prefrontal cortex (VmPFC) is believed to play a critical role in addiction disorders, and glutamatergic projections from the prefrontal cortex to several regions of the brain are present in reward circuits. Proton magnetic resonance spectroscopy was also performed to assess the difference in glutamate levels in VmPFC between AD patients and HC. The results showed that the strength of functional connectivity in the reward circuit was generally attenuated in AD patients, and the reciprocal enhancement of activity between the right insula, left thalamus and VmPFC was found to be significantly greater in AD patients. It is worth noting that although glutamate levels in the VmPFC did not show significant differences between the two groups, the level of glutamate in the VmPFC was significantly correlated with RSFC. We hope that the current findings will help us to develop new intervention models based on the important role of the VmPFC in AD.

Microplastics in aquatic environments: A comprehensive review of toxicity, removal, and remediation strategies.

The occurrence of microplastics (MPs) in aquatic environments has been a global concern because they are toxic and persistent and may serve as a vector for many legacies and emerging pollutants. MPs are discharged to aquatic environments from different sources, especially from wastewater plants (WWPs), causing severe impacts on aquatic organisms. This study mainly aims to review the Toxicity of MPs along with plastic additives in aquatic organisms at various trophic compartments and available remediation methods/strategies for MPs in aquatic environments. Occurrences of oxidative stress, neurotoxicity, and alterations in enzyme activity, growth, and feeding performance were identical in fish due to MPs toxicity. On the other hand, growth inhibition and ROS formation were observed in most of the microalgae species. In zooplankton, potential impacts were acceleration of premature molting, growth retardation, mortality increase, feeding behaviour, lipid accumulation, and decreased reproduction activity. MPs togather with additive contaminants could also exert some toxicological impacts on polychaete, including neurotoxicity, destabilization of the cytoskeleton, reduced feeding rate, growth, survivability and burrowing ability, weight loss, and high rate of mRNA transcription. Among different chemical and biological treatments for MPs, high removal rates have been reported for coagulation and filtration (>86.5 %), electrocoagulation (>90 %), advanced oxidation process (AOPs) (30 % to 95 %), primary sedimentation/Grit chamber (16.5 % to 58.84 %), adsorption removal technique (>95 %), magnetic filtration (78 % to 93 %), oil film extraction (>95 %), and density separation (95 % to 100 %). However, desirable extraction methods are required for large-scale research in MPs removal from aquatic environments.

Vanadium-Tailored Silicon Composite with Furthered Ion Diffusion Behaviors for Longevity Lithium-Ion Storage.

As one of the promising anode materials, silicon has attracted much attention due to its high theoretical specific capacity (∼3579 mAh g-1) and suitable lithium alloying voltage (0.1-0.4 V). Nevertheless, the enormous volume expansion (∼300%) in the process of lithium alloying has a great negative effect on its cyclic stability, which seriously restricts the large-scale industrial preparation of silicon anodes. Herein, we design a facile synthesis strategy combining vanadium doping and carbon coating to prepare a silicon-based composite (V-Si@C). The prepared V-Si@C composite does not merely show improved conductivity but also improved electrochemical kinetics, attributed to the enlarged lattice spacing by V doping. Additionally, the superiority of this doping strategy accompanied by microstructure change is embodied in the relieved volume changes during the repeated charging/discharging process. Notably, the initial capacity of the advanced V-Si@C electrode is 904 mAh g-1 (1 A g-1) and still holds at 1216 mAh g-1 even after 600 cycles, showing superior electrochemical performance. This study offers an alternative direction for the large-scale preparation of high-performance silicon-based anodes.

Biosynthesis of Isonitrile Lipopeptide Metallophores from Pathogenic Mycobacteria.

Isonitrile lipopeptides (INLPs) are known to be related to the virulence of pathogenic mycobacteria by mediating metal transport, but their biosynthesis remains obscure. In this work, we use in vitro biochemical assays, site-directed mutagenesis, chemical synthesis, and spectroscopy techniques to scrutinize the activity of core enzymes required for INLP biosynthesis in mycobacteria. Compared to environmental Streptomyces, pathogenic Mycobacterium employ a similar chemical logic and enzymatic machinery in INLP biosynthesis, differing mainly in the fatty-acyl chain length, which is controlled by multiple enzymes in the pathway. Our in-depth study on the non-heme iron(II) and α-ketoglutarate-dependent dioxygenase for isonitrile generation, including Rv0097 from Mycobacterium tuberculosis (Mtb), demonstrates that it recognizes a free-standing small molecule substrate, different from the recent hypothesis that a carrier protein is required for Rv0097 in Mtb. A key residue in Rv0097 is further identified to dictate the varied fatty-acyl chain length specificity between Streptomyces and Mycobacterium.

The IL17 signaling pathway: A potential signaling pathway mediating gill hyperplasia and inflammation under ammonia nitrogen stress was identified by multi-omics analysis.

Ammonia nitrogen is extremely toxic to aquatic animals, and is also the most common pollutant in the aquatic environment. In order to investigate the effect of high concentration of ambient ammonia nitrogen on fish gills, two groups, including a high ammonia group (T group: TAN = 2.5 mg/L, 10 % 96 h LC50) and a control group (Z group: total ammonia nitrogen (TAN) = 0 mg/L) were set up in this study. The effects of chronic ammonia stress on the gills of Pelteobagrus fulvidraco were investigated by histopathological, enzymatic, transcriptomic and proteomic analyses after 28 d of stress at different ammonia nitrogen concentrations. Histopathological observations revealed significant inflammatory cell infiltration, necrotic and abscission at the base of the gill filaments, and massive proliferation of cells at the base of the gill lamellae. Ammonia nitrogen stress led to increased reactive oxygen species (ROS) content and decreased catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) activities in gills, indicating significant oxidative stress in gills. And further transcriptomic analysis revealed that 807 differential expression genes (DEGs) were generated in the gills, of which 587 DEGs were up-regulated and 220 DEGs were down-regulated. In addition, proteomics analysis identified 1073 differential expression proteins (DEPs) in gills, including 983 up- and 90 down-regulated DEPs. Pathway enrichment analysis of the DEGs and DEPs revealed that multiple inflammation-related signaling pathways were activated in the gill, including the significantly enriched IL17 signaling pathway. This suggests that IL17 signaling pathway might have a significant impact during signaling transduction. Further analysis of network regulation by mapping DEGs and DEPs to KEGG pathway revealed that IL17 signaling pathway mediated inflammation and cell proliferation in gills under ammonia stress. The results of this study provided new insights into the response of fish gills to ammonia nitrogen stress, and the IL17 signaling pathway may be a potential therapeutic target for reducing ammonia nitrogen gill toxicity.

Unlocking Charge Transfer Limitations for Extreme Fast Charging of Li-Ion Batteries.

Extreme fast charging (XFC) of high-energy Li-ion batteries is a key enabler of electrified transportation. While previous studies mainly focused on improving Li ion mass transport in electrodes and electrolytes, the limitations of charge transfer across electrode-electrolyte interfaces remain underexplored. Herein we unravel how charge transfer kinetics dictates the fast rechargeability of Li-ion cells. Li ion transfer across the cathode-electrolyte interface is found to be rate-limiting during XFC, but the charge transfer energy barrier at both the cathode and anode have to be reduced simultaneously to prevent Li plating, which is achieved through electrolyte engineering. By unlocking charge transfer limitations, 184 Wh kg-1 pouch cells demonstrate stable XFC (10-min charge to 80 %) which is otherwise unachievable, and the lifetime of 245 Wh kg-1 21700 cells is quintupled during fast charging (25-min charge to 80 %).

Experimental demonstration of skyrmionic magnetic tunnel junction at room temperature.

Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last decade, while electrical detection compatible with semiconductor processes has not been achieved, and this is considered one of the most crucial gaps regarding the use of skyrmions in real applications. Here, we report the direct observation of nanoscale skyrmions in CoFeB/MgO-based magnetic tunnel junction devices at room temperature. High-resolution magnetic force microscopy imaging and tunneling magnetoresistance measurements are used to illustrate the electrical detection of skyrmions, which are stabilized under the cooperation of interfacial Dzyaloshinskii-Moriya interaction, perpendicular magnetic anisotropy, and dipolar stray field. This skyrmionic magnetic tunnel junction shows a stable nonlinear multilevel resistance thanks to its topological nature and tunable density of skyrmions under current pulse excitation. These features provide important perspectives for spintronics to realize high-density memory and neuromorphic computing.

Nitrogen Balance on Ni-N-C Promotor for High-Energy Lithium-Sulfur Pouch Cells.

The viability of lithium-sulfur (Li-S) batteries toward real implementation directly correlates with unlocking lithium polysulfide (LiPS) evolution reactions. Along this line, designing promotors with the function of synchronously relieving LiPS shuttle and promoting sulfur conversion is critical. Herein, the nitrogen evolution on hierarchical and atomistic Ni-N-C electrocatalyst, mainly pertaining to the essential subtraction, reservation and coordination of nitrogen atoms, is manipulated to attain favorable Li-S pouch cell performances. Such rational evolution behavior realizes the "nitrogen balance" in simultaneously regulating the Ni-N coordination environment, Ni single atom loading, abundant vacancy defects, active nitrogen and electron conductivity, and maximizing the electrocatalytic activity elevation of Ni-N-C system. With such merit, the cathode harvests favorable performances in a soft-packaged pouch cell prototype even under high sulfur mass loading and lean electrolyte usage. A specific energy density up to 405.1 Wh kg-1 is harvested by the 0.5-Ah-level pouch cell.

Operando Quantified Lithium Plating Determination Enabled by Dynamic Capacitance Measurement in Working Li-Ion Batteries.

The access to full performance of state-of-the-art Li-ion batteries (LIBs) is hindered by the mysterious lithium plating behavior. A rapid quantified lithium plating determination method compatible with actual working conditions is an urgent necessity for safe working LIBs. In this contribution, the relationship between electrical double layer (EDL) capacitance and electrochemical active surface area (ECSA) of graphite anodes during the Li-ion intercalation and Li plating processes is unveiled. We propose an operando lithium plating determination method based on the dynamic capacitance measurement (DCM) test. Reasonable selection of alternating current (AC) frequency protects the anodic responses from the interference of cathodic responses, which allows DCM to be applied in practical LIBs. The onset of lithium plating can be quantitatively traced, demonstrating the promise for real-time operando determination for lithium plating in a working battery.

Simultaneous Isolation and Identification of Largemouth Bass Virus and Rhabdovirus from Moribund Largemouth Bass (Micropterus salmoides).

Largemouth bass is an important commercially farmed fish in China, but the rapid expansion of its breeding has resulted in increased incidence of diseases caused by bacteria, viruses and parasites. In this study, moribund largemouth bass containing ulcer foci on body surfaces indicated the most likely pathogens were iridovirus and rhabdovirus members and this was confirmed using a combination of immunohistochemistry, cell culture, electron microscopy and conserved gene sequence analysis. We identified that these fish had been co-infected with these viruses. We observed bullet-shaped virions (100−140 nm long and 50−100 nm in diameter) along with hexagonal virions with 140 nm diameters in cell culture inoculated with tissue homogenates. The viruses were plaque purified and a comparison of the highly conserved regions of the genome of these viruses indicated that they are most similar to largemouth bass virus (LMBV) and hybrid snakehead rhabdovirus (HSHRV), respectively. Regression infection experiments indicated fish mortalities for LMBV-FS2021 and HSHRV-MS2021 were 86.7 and 11.1%, respectively. While co-infection resulted in 93.3% mortality that was significantly (p < 0.05) higher than the single infections even though the viral loads differed by >100-fold. Overall, we simultaneously isolated and identified LMBV and a HSHRV-like virus from diseased largemouth bass, and our results can provide novel ideas for the prevention and treatment of combined virus infection especially in largemouth bass.

Rational Design of Space-Confined Mn-Based Heterostructures with Synergistic Interfacial Charge Transport and Structural Integrity for Lithium Storage.

Manganese-based compounds are expected to become promising candidates for lithium-ion battery anodes by virtue of their high theoretical specific capacity and low conversion potential. However, their application is hindered by their inferior electrical conductivity and drastic volume variations. In this work, a unique heterostructure composed of MnO and MnS spatially confined in pyrolytic carbon microspheres (MnO@MnS/C) was synthesized through an integrated solvothermal method, calcination, and low-temperature vulcanization technology. In this architecture, heterostructured MnO@MnS nanoparticles (∼10 nm) are uniformly embedded into the carbonaceous microsphere matrix to maintain the structural stability of the composite. Benefiting from the combination of structural and compositional features, the MnO@MnS/C enables abundance in electrochemically active sites, alleviated volumetric variation, a rich conductive network, and enhanced lithium-ion diffusion kinetics, thus yielding remarkable rate capability (1235 mAh·g-1 at 0.2 A·g-1 and 608 mAh·g-1 at 3.2 A·g-1) and exceptional cycling stability (522 mAh·g-1 after 2000 cycles at 3.0 A·g-1) as a competitive anode material for lithium-ion batteries. Density functional theory calculations unveil that the heterostructure promotes the transfer of electrons with improved conductivity and also accelerates the migration of lithium ions with reduced polarization resistance. This combined with the enhancement brought by spatial confinement endows the MnO@MnS/C with remarkable lithium storage performance.