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1.
Front Neurorobot ; 18: 1364587, 2024.
Article in English | MEDLINE | ID: mdl-38774520

ABSTRACT

Multiagent Reinforcement Learning (MARL) has been well adopted due to its exceptional ability to solve multiagent decision-making problems. To further enhance learning efficiency, knowledge transfer algorithms have been developed, among which experience-sharing-based and action-advising-based transfer strategies share the mainstream. However, it is notable that, although there exist many successful applications of both strategies, they are not flawless. For the long-developed action-advising-based methods (namely KT-AA, short for knowledge transfer based on action advising), their data efficiency and scalability are not satisfactory. As for the newly proposed experience-sharing-based knowledge transfer methods (KT-ES), although the shortcomings of KT-AA have been partially overcome, they are incompetent to correct specific bad decisions in the later learning stage. To leverage the superiority of both KT-AA and KT-ES, this study proposes KT-Hybrid, a hybrid knowledge transfer approach. In the early learning phase, KT-ES methods are employed, expecting better data efficiency from KT-ES to enhance the policy to a basic level as soon as possible. Later, we focus on correcting specific errors made by the basic policy, trying to use KT-AA methods to further improve the performance. Simulations demonstrate that the proposed KT-Hybrid outperforms well-received action-advising- and experience-sharing-based methods.

2.
Cell Death Discov ; 10(1): 262, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38811540

ABSTRACT

The mechanism of hypoxia in chemoresistance of pancreatic ductal adenocarcinoma (PDAC) remains elusive. In this study, we revealed the essential role of miR-485-3p in PDAC, particularly its impact on cancer stemness and gemcitabine resistance under hypoxic conditions. We found substantial downregulation of miR-485-3p in PDAC tissues, with lower expression correlating to poor patient outcomes. Mechanistically, miR-485-3p influenced stemness characteristics, as evidenced by reduced tumor-sphere formation and increased sensitivity to gemcitabine upon overexpression. Moreover, we identified SOX9 and SLC7A11 as two targets of miR-485-3p, which play a vital role in stemness and ferroptosis. Under the hypoxic condition, DNMT3B expression was upregulated, leading to hypermethylation of the miR-485-3p promoter region. The reduced miR-485-3p expression promoted stemness and chemoresistance of PDAC. In conclusion, our findings elucidate the intricate interplay of hypoxia, epigenetic modifications, and ferroptosis in PDAC and shed light on potential avenues for targeted interventions that modulate cancer stemness and chemosensitivity, offering prospects for improved therapeutic strategies for PDAC.

3.
Nat Commun ; 15(1): 2139, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38459016

ABSTRACT

The pressing demand for sustainable energy storage solutions has spurred the burgeoning development of aqueous zinc batteries. However, kinetics-sluggish Zn2+ as the dominant charge carriers in cathodes leads to suboptimal charge-storage capacity and durability of aqueous zinc batteries. Here, we discover that an ultrathin two-dimensional polyimine membrane, featured by dual ion-transport nanochannels and rich proton-conduction groups, facilitates rapid and selective proton passing. Subsequently, a distinctive electrochemistry transition shifting from sluggish Zn2+-dominated to fast-kinetics H+-dominated Faradic reactions is achieved for high-mass-loading cathodes by using the polyimine membrane as an interfacial coating. Notably, the NaV3O8·1.5H2O cathode (10 mg cm-2) with this interfacial coating exhibits an ultrahigh areal capacity of 4.5 mAh cm-2 and a state-of-the-art energy density of 33.8 Wh m-2, along with apparently enhanced cycling stability. Additionally, we showcase the applicability of the interfacial proton-selective coating to different cathodes and aqueous electrolytes, validating its universality for developing reliable aqueous batteries.

4.
Adv Mater ; 36(19): e2313621, 2024 May.
Article in English | MEDLINE | ID: mdl-38316395

ABSTRACT

Rechargeable aqueous zinc batteries are potential candidates for sustainable energy storage systems at a grid scale, owing to their high safety and low cost. However, the existing cathode chemistries exhibit restricted energy density, which hinders their extensive applications. Here, a tellurium redox-amphoteric conversion cathode chemistry is presented for aqueous zinc batteries, which delivers a specific capacity of 1223.9 mAh gTe -1 and a high energy density of 1028.0 Wh kgTe -1. A highly concentrated electrolyte (30 mol kg-1 ZnCl2) is revealed crucial for initiating the Te redox-amphoteric conversion as it suppresses the H2O reactivity and inhibits undesirable hydrolysis of the Te4+ product. By carrying out multiple operando/ex situ characterizations, the reversible six-electron Te2-/Te0/Te4+ conversion with TeCl4 is identified as the fully charged product and ZnTe as the fully discharged product. This finding not only enriches the conversion-type battery chemistries but also establishes a critical step in exploring redox-amphoteric materials for aqueous zinc batteries and beyond.

5.
Front Immunol ; 14: 1247038, 2023.
Article in English | MEDLINE | ID: mdl-37662918

ABSTRACT

The loach (Misgurnus anguillicaudatus), a small commercial fish that is widely cultivated for its high-quality protein, vitamins, minerals, and essential amino acid, is a member of the genus Misgurnus and the family Cyprinidae. In this study, we gave the LPS-injected loach fermented soybean meal and used transcriptome sequencing to investigate the impact of the fermented soybean powder on the loach's immune system. 3384 up-regulated genes and 12116 down-regulated genes were found among the 15500 differentially expressed genes, according to the results. The differentially expressed genes were shown to be involved in cellular processes, metabolic processes, cellular anatomical entities, and binding, according to the Go functional annotation. Meanwhile, the KEGG enrichment analysis indicated that the soybean fermented powder treated groups showed significant differences in DNA replication, Nucleotide excision repair, Fanconi anemia pathway, and Base excision repair pathways, suggesting that these pathways are closely related to the enhancement of the immune function of loach by soybean fermented powder. The particular conclusions not exclusively can provide a new conception for the rational utilization of soybean fermented powder but also can provide theoretical guidance for the subsequent healthy breeding of loach.


Subject(s)
Cypriniformes , Fish Diseases , Glycine max , Lipopolysaccharides , Glycine max/chemistry , Cypriniformes/genetics , Cypriniformes/immunology , Random Allocation , Gene Expression Regulation , Fish Diseases/genetics , Fish Diseases/immunology , Aquaculture , Fermented Foods , Immunity
6.
Front Psychol ; 14: 1101396, 2023.
Article in English | MEDLINE | ID: mdl-37484075

ABSTRACT

Interest is one of the main factors motivating an individual's behavior, and its effect in the learning process has been widely confirmed in educational psychology. The purpose of this study was to explore the influence of individual interest, topic interest and situational interest on the user's video click behavior in the online video browsing situation. We constructed an online experiment in which each participant was asked to use questionnaires to assess their responses to video categories, titles, and covers from the video-sharing website, Bilibili. Based on these responses, we obtained individual interests, topic interests, situational interests, and click behavior of the participants toward the videos. Correlation, regression and mediation analyses were conducted to explore the effects and mechanisms of the three interests on click behavior. The results found: (1) individual interest may have a positive but relatively weaker effect on click behavior, and (2) topic interest and situational interest positively predicted click behavior in all categories. The mediation analysis found: (1) in the otomads and fashion categories, the effect of individual interest on click behavior was partially mediated by topic and situational interest, and (2) in the anime, digits, life, dance, music, game, entertainment, and knowledge categories, the effect of individual interest on click behavior was fully mediated by topic interest and situational interest. These results revealed the facilitating effects and different effect modes of individual, topic, and situational interest on click behavior. These findings shed light on the influence mechanism of interests on video click behavior in different video categories and provide new insights into related applications such as recommender.

7.
Angew Chem Int Ed Engl ; 62(30): e202306091, 2023 Jul 24.
Article in English | MEDLINE | ID: mdl-37204021

ABSTRACT

Emerging rechargeable aluminium batteries (RABs) offer a sustainable option for next-generation energy storage technologies with low cost and exemplary safety. However, the development of RABs is restricted by the limited availability of high-performance cathode materials. Herein, we report two polyimide two-dimensional covalent organic frameworks (2D-COFs) cathodes with redox-bipolar capability in RAB. The optimal 2D-COF electrode achieves a high specific capacity of 132 mAh g-1 . Notably, the electrode presents long-term cycling stability (with a negligible ≈0.0007 % capacity decay per cycle), outperforming early reported organic RAB cathodes. 2D-COFs integrate n-type imide and p-type triazine active centres into the periodic porous polymer skeleton. With multiple characterizations, we elucidate the unique Faradaic reaction of the 2D-COF electrode, which involves AlCl2+ and AlCl4 - dual-ions as charge carriers. This work paves the avenue toward novel organic cathodes in RABs.

8.
World J Diabetes ; 14(3): 234-254, 2023 Mar 15.
Article in English | MEDLINE | ID: mdl-37035233

ABSTRACT

BACKGROUND: Peripheral arterial disease (PAD) has become one of the leading causes of disa-bility and death in diabetic patients. Restoring blood supply to the hindlimbs, especially by promoting arteriogenesis, is currently the most effective strategy, in which endothelial cells play an important role. Tongxinluo (TXL) has been widely used for the treatment of cardio-cerebrovascular diseases and extended for diabetes-related vascular disease. AIM: To investigate the effect of TXL on diabetic PAD and its underlying mechanisms. METHODS: An animal model of diabetic PAD was established by ligating the femoral artery of db/db mice. Laser Doppler imaging and micro-computed tomography (micro-CT) were performed to assess the recovery of blood flow and arteriogenesis. Endothelial cell function related to arteriogenesis and cellular pyroptosis was assessed using histopathology, Western blot analysis, enzyme-linked immuno-sorbent assay and real-time polymerase chain reaction assays. In vitro, human vascular endothelial cells (HUVECs) and human vascular smooth muscle cells (VSMCs) were pretreated with TXL for 4 h, followed by incubation in high glucose and hypoxia conditions to induce cell injury. Then, indicators of HUVEC pyroptosis and function, HUVEC-VSMC interactions and the migration of VSMCs were measured. RESULTS: Laser Doppler imaging and micro-CT showed that TXL restored blood flow to the hindlimbs and enhanced arteriogenesis. TXL also inhibited endothelial cell pyroptosis via the reactive oxygen species/nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3/Caspase-1/GSDMD signaling pathway. In addition, TXL restored endothelial cell functions, including maintaining the balance of vasodilation, acting as a barrier to reduce inflammation, and enhancing endothelial-smooth muscle cell interactions through the Jagged-1/Notch-1/ephrin-B2 signaling pathway. Similar results were observed in vitro. CONCLUSION: TXL has a pro-arteriogenic effect in the treatment of diabetic PAD, and the mechanism may be related to the inhibition of endothelial cell pyroptosis, restoration of endothelial cell function and promotion of endothelial cell-smooth muscle cell interactions.

9.
Plant J ; 114(5): 1115-1131, 2023 06.
Article in English | MEDLINE | ID: mdl-37095649

ABSTRACT

Plants developed sophisticated mechanisms to perceive environmental stimuli and generate appropriate signals to maintain optimal growth and stress responses. A fascinating strategy employed by plants is the use of long-distance mobile signals which can trigger local and distant responses across the entire plant. Some metabolites play a central role as long-distance mobile signals allowing plants to communicate across tissues and mount robust stress responses. In this review, we summarize the current knowledge regarding the various long-distance mobile metabolites and their functions in stress response and signaling pathways. We also raise questions with respect to how we can identify new mobile metabolites and engineer them to improve plant health and resilience.


Subject(s)
Plants , Signal Transduction , Signal Transduction/physiology , Plants/metabolism
10.
Am J Transl Res ; 15(2): 817-833, 2023.
Article in English | MEDLINE | ID: mdl-36915723

ABSTRACT

BACKGROUND: The expression of aberrant interferon-stimulated gene 15 (ISG15) is connected with various human diseases, including cancer. ISG15 is involved in tumor formation and metastasis. However, its role in osteosarcoma is uncertain. METHODS: ISG15 expression in pan-cancer from RNA Sequencing data were obtained from The Cancer Genome Atlas (TCGA) and Genotype Tissue Expression (GTEx) databases. The relationship between ISG15 expression and prognosis was assessed through TCGA clinical survival data. Immunohistochemistry (IHC) images of ISG15 were retrieved using the Human Protein Atlas to analyze the differences in selected normal and tumor tissues. Gene enrichment analysis and signaling pathway analysis were used to assess the potential role of ISG15 in sarcoma, and the correlation between ISG15 expressions and immune cell infiltration levels was estimated by immune infiltration analysis. The expression levels of ISG15 were assessed by qRT-PCR and IHC. Colony formation, wound healing assay and transwell assay were used to detect the effects of ISG15 on the biological behaviors of osteosarcoma cells. The correlation between ISG15 levels and CD8+/CD68+ cells was further examined by double-labeled immunofluorescence. The chemotactic effect of ISG15 on CD8+/CD68+ cells was demonstrated by chemotactic experiments and flow cytometry. RESULTS: ISG15 was highly expressed in most cancers, while high ISG15 expression was significantly correlated with poor overall survival. Gene enrichment analysis in sarcoma suggested that antigen processing and presentation might be involved in the oncogenic mechanism of ISG15. Further immune infiltration analysis showed that high ISG15 expression might reflect the infiltration level of certain immune cells. Additionally, our verification showed that ISG15 was significantly related to the occurrence and metastasis of osteosarcoma, and knockdown of ISG15 significantly altered cell biological behavior, resulting in decreased proliferation, migration and invasion capabilities of osteosarcoma cells. The high expression of ISG15 in osteosarcoma tissue was associated with a high level of CD68+ immune cell infiltration while a low level of CD8+ T cell infiltration. CD68+ immune cells were recruited in vitro by overexpression of ISG15, which on the contrary could weaken the chemotaxis of CD8+ T cells. CONCLUSION: High ISG15 expression is an inherent feature of osteosarcoma and triggers tumorigenesis and metastasis by regulating tumor immunogenicity. ISG15 is expected to be the target of osteosarcoma treatment.

11.
Nat Commun ; 14(1): 760, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36765051

ABSTRACT

The anion-intercalation chemistries of graphite have the potential to construct batteries with promising energy and power breakthroughs. Here, we report the use of an ultrathin, positively charged two-dimensional poly(pyridinium salt) membrane (C2DP) as the graphite electrode skin to overcome the critical durability problem. Large-area C2DP enables the conformal coating on the graphite electrode, remarkably alleviating the electrolyte. Meanwhile, the dense face-on oriented single crystals with ultrathin thickness and cationic backbones allow C2DP with high anion-transport capability and selectivity. Such desirable anion-transport properties of C2DP prevent the cation/solvent co-intercalation into the graphite electrode and suppress the consequent structure collapse. An impressive PF6--intercalation durability is demonstrated for the C2DP-covered graphite electrode, with capacity retention of 92.8% after 1000 cycles at 1 C and Coulombic efficiencies of > 99%. The feasibility of constructing artificial ion-regulating electrode skins with precisely customized two-dimensional polymers offers viable means to promote problematic battery chemistries.

13.
Heliyon ; 8(11): e11346, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36387570

ABSTRACT

Diabetic foot has become one of the leading causes of disability and death in diabetic patients. Restoring blood supply to the lower limbs, especially by increasing collateral vessels, is currently the most effective strategy. We report a 70-year-old female patient diagnosed with diabetic foot who was treated with integrated traditional Chinese and Western medicine. Western medicine treatment includes blood glucose control, lipid regulation, plaque stabilization, antiplatelet coagulation and anti-inflammation. Traditional Chinese medicine (TCM) treatment is based on the principles of promoting blood circulation and relieving pain, benefiting Qi and activating blood circulation, including oral Chinese medicine Tongxinluo and electro-acupuncture treatment. The vascular morphology of the patient's lower limbs and the levels of glucolipid metabolism were evaluated before and after treatment. The results showed that after treatment, the patient had increased blood flow in the lower limbs, reduced plaque in the femoral arteries, and improved levels of glucolipid metabolism.

15.
Ann Ital Chir ; 92: 280-285, 2022.
Article in English | MEDLINE | ID: mdl-36052458

ABSTRACT

AIM: Recurrent episodes of chronic tonsillitis (CT) can affect a patient's quality of life, physical and mental health. Clinicians often perform surgeries to remove them. Traditional surgical methods are varied, despite their advantages. However, this remains controversial. This study aimed to examine both the safety and efficacy of low-temperature plasma tonsillectomy (LTPT) in treatment of chronic tonsillitis, which may provide a substitute for clinicians and compensate for the short supply of therapeutic procedures. METHODS AND ANALYSIS: This protocol is guided by the Preferred Reporting Items for Systematic. REVIEW AND META-ANALYSIS: Protocols (PRISMA-P) and by the Cochrane Collaboration Handbook. We will formulate strict inclusion and exclusion criteria in English databases (PubMed, EMBASE, and Web of Science) and search literature in different clinical registration platforms (Cochrane Library). The including articles were evaluated by the Cochrane RCT evaluation criteria. The primary main endpoints will include the duration of operation, blood loss during surgery, time of formation and exfoliation of the pseudomembrane, average pain and duration post-operation, and time for normal diet. The Secondary endpoints will include complications of postoperative bleeding and infection. Stata 15.0 will be used for data analysis. Subgroup analysis, sensitivity analysis, and meta-regression were used to detect the sources of heterogeneity. Begg's Test will quantitatively detect publication bias quantitatively. ETHICS AND DISSEMINATION: The results of this meta-analysis and meta-regression will be disseminated through publication in a peer-reviewed journal. The data used in this meta-analysis will not contain individual patient data; therefore, ethical approval is not required. KEY WORDS: Chronic tonsillitis, Low-temperature plasma tonsillectomy, Meta-analysis, Protocol, Systematic review.


Subject(s)
Tonsillectomy , Tonsillitis , Chronic Disease , Humans , Meta-Analysis as Topic , Quality of Life , Research Design , Systematic Reviews as Topic , Temperature , Tonsillitis/surgery
16.
Article in English | MEDLINE | ID: mdl-35954551

ABSTRACT

As suicides incurred by the COVID-19 outbreak keep happening in many countries, researchers have raised concerns that the ongoing pandemic may lead to "a wave of suicides" in society. Suicidal ideation (SI) is a critical factor in conducting suicide intervention and also an important indicator for measuring people's mental health. Therefore, it is vital to identify the influencing factors of suicidal ideation and its psychological mechanism during the outbreak. Based on the terror management theory, in the present study we conducted a social media big data analysis to explore the joint effects of mortality salience (MS), negative emotions (NE), and cultural values on suicidal ideation in 337 regions on the Chinese mainland. The findings showed that (1) mortality salience was a positive predictor of suicidal ideation, with negative emotions acting as a mediator; (2) individualism was a positive moderator in the first half-path of the mediation model; (3) collectivism was a negative moderator in the first half-path of the mediation model. Our findings not only expand the application of the terror management theory in suicide intervention but provide some insights into post-pandemic mental healthcare. Timely efforts are needed to provide psychological interventions and counseling on outbreak-caused negative emotions in society. Compared with people living in collectivism-prevailing regions, those living in individualism-prevailing regions may be more vulnerable to mortality salience and negative emotions and need more social attention.


Subject(s)
COVID-19 , Suicide , COVID-19/epidemiology , Emotions , Humans , Pandemics , Suicidal Ideation
17.
Fish Shellfish Immunol ; 127: 623-632, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35810964

ABSTRACT

As an inflammatory cytokine of the interleukin-20 (IL-20) subfamily, IL-20 has various functions in immune defenses, inflammatory diseases, tissue regeneration, cancer, and metabolism. Although the characteristics and functions of mammalian IL-20 have been clarified, those of fish IL-20 remain unclear. In this study, the IL-20 gene from the snakehead Channa argus (shIL-20) was cloned and functionally characterized. Similar to the IL-20 homologues of other species, the shIL-20 has a five exon/four intron structure in the coding region. The open reading frame of shIL-20 consists of 528 base pairs and encodes 175 amino acids (aa), including a signal peptide (aa 1-24) and a mature peptide (aa 25-175). The mature shIL-20 protein has six conserved cysteine residues, which occur in the IL-20 proteins of all species analyzed, and an additional cysteine residue (Cys-82) found only in the IL-20 proteins of several teleosts. The modeled tertiary structure of shIL-20 is similar with that of Homo sapiens IL-20. The shIL-20 was expressed constitutively in all the tissues analyzed, and its transcription was induced in the spleen and head kidney by Aeromonas schubertii and Nocardia seriolae in vivo and in head kidney leukocytes (HKLs) by lipoteichoic acid, lipopolysaccharide, and polyinosinic-polycytidylic acid in vitro. The recombinant shIL-20 protein induced the transcription of tumor necrosis factor α1 (TNF-α1), TNF-α2, IL-1ß, and endogenous shIL-20, and promoted the proliferation of HKLs. In conclusion, these findings demonstrate that shIL-20 participates in the immune response to bacterial invasion and promotes leukocyte proliferation, offering new insights into the functions of fish IL-20 during pathogen invasion.


Subject(s)
Cysteine , Fish Diseases , Animals , Bacteria/metabolism , Cell Proliferation , Fish Proteins/chemistry , Fishes/genetics , Head Kidney/metabolism , Interleukins , Leukocytes/metabolism , Mammals/metabolism , Phylogeny
18.
Fish Shellfish Immunol ; 123: 207-217, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35278639

ABSTRACT

Interleukin-21 (IL-21), a crucial immune regulatory molecule, belongs to the common γ-chain family of type I cytokines, and exerts pleiotropic effects on multiple immune cell types in mammals. However, the characteristics and functions of fish IL-21 remain unclear. To further investigate the molecular mechanism of IL-21 in teleosts, we first cloned and identified the IL-21 gene (designated shIL-21) of the snakehead (Channa argus). The full-length open reading frame of shIL-21 is 438 bp in length, and encodes a predicted protein of 145 amino acid residues. A sequence analysis showed that shIL-21 has the typical structural characteristics of other IL-21 proteins, containing four α-helices and four conserved cysteine residues. In a phylogenetic analysis, shIL-21 clustered within a subgroup of IL-21 proteins from other teleost species and shared its closest evolutionary relationship with that of Lates calcarifer. The expression analysis showed that shIL-21 was ubiquitously expressed in all the healthy snakehead tissues tested, albeit at different levels. After infection with Nocardia seriolae or Aeromonas schubertii, the relative expression of shIL-21 was mainly upregulated in the head kidney and spleen in vivo. Similarly, after stimulation with the three pathogen analogues lipoteichoic acid, lipopolysaccharides, and polyinosinic-polycytidylic acid, the expression of shIL-21 was also induced in head kidney leukocytes in vitro. A recombinant shIL-21 protein was expressed and purified, and promoted the proliferation of head kidney leukocytes, induced the expression of genes encoding critical signaling molecules in the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathway, including JAK1, JAK3, STAT1, and STAT3, and induced the expression of endogenous shIL-21 and genes encoding several key proinflammatory cytokines (tumor necrosis factor-α, interferon-γ, and IL-1ß). Taken together, these preliminary findings suggest that shIL-21 is involved in the immune defense against bacterial infection, in leukocyte proliferation, and in the activation of the JAK-STAT pathway. They thus extend the functional studies of IL-21 in teleosts.


Subject(s)
Fish Diseases , Janus Kinases , Animals , Cell Proliferation , Fishes/genetics , Interleukins/genetics , Interleukins/metabolism , Janus Kinases/genetics , Leukocytes/metabolism , Mammals/metabolism , Phylogeny , STAT Transcription Factors/genetics , Signal Transduction
19.
ChemSusChem ; 15(10): e202200039, 2022 May 20.
Article in English | MEDLINE | ID: mdl-35302711

ABSTRACT

Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc-air batteries. However, Zn deposition has received little attention in organic solvents with much higher ionic conductivity and current efficiency. In this study, a Zn-betaine complex is synthesized by using ZnO and betainium bis[(trifluoromethyl)sulfonyl]imide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite-free Zn electrodeposition at room temperature with current efficiencies of up to 86 %. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc-air battery with these electrodes shows an open-circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mA cm-2 or 33 cycles at 20 mA cm-2 , and allows intermediate cycling at 100 mA cm-2 .

20.
Adv Mater ; 34(15): e2108682, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35148441

ABSTRACT

2D transition metal carbides and/or nitrides, so-called MXenes, are noted as ideal fast-charging cation-intercalation electrode materials, which nevertheless suffer from limited specific capacities. Herein, it is reported that constructing redox-active phosphorus-oxygen terminals can be an attractive strategy for Nb4 C3 MXenes to remarkably boost their specific capacities for ultrafast Na+ storage. As revealed, redox-active terminals with a stoichiometric formula of PO2 - display a metaphosphate-like configuration with each P atom sustaining three PO bonds and one PO dangling bond. Compared with conventional O-terminals, metaphosphate-like terminals empower Nb4 C3 (denoted PO2 -Nb4 C3 ) with considerably enriched carrier density (fourfold), improved conductivity (12.3-fold at 300 K), additional redox-active sites, boosted Nb redox depth, nondeclined Na+ -diffusion capability, and buffered internal stress during Na+ intercalation/de-intercalation. Consequently, compared with O-terminated Nb4 C3 , PO2 -Nb4 C3 exhibits a doubled Na+ -storage capacity (221.0 mAh g-1 ), well-retained fast-charging capability (4.9 min at 80% capacity retention), significantly promoted cycle life (nondegraded capacity over 2000 cycles), and justified feasibility for assembling energy-power-balanced Na-ion capacitors. This study unveils that the molecular-level design of MXene terminals provides opportunities for developing simultaneously high-capacity and fast-charging electrodes, alleviating the energy-power tradeoff typical for energy-storage devices.

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