Mechanistic insights into phosphoactivation of SLAC1 in guard cell signaling.

Stomata in leaves regulate gas (carbon dioxide and water vapor) exchange and water transpiration between plants and the atmosphere. SLow Anion Channel 1 (SLAC1) mediates anion efflux from guard cells and plays a crucial role in controlling stomatal aperture. It serves as a central hub for multiple signaling pathways in response to environmental stimuli, with its activity regulated through phosphorylation via various plant protein kinases. However, the molecular mechanism underlying SLAC1 phosphoactivation has remained elusive. Through a combination of protein sequence analyses, AlphaFold-based modeling and electrophysiological studies, we unveiled that the highly conserved motifs on the N- and C-terminal segments of SLAC1 form a cytosolic regulatory domain (CRD) that interacts with the transmembrane domain(TMD), thereby maintaining the channel in an autoinhibited state. Mutations in these conserved motifs destabilize the CRD, releasing autoinhibition in SLAC1 and enabling its transition into an activated state. Our further studies demonstrated that SLAC1 activation undergoes an autoinhibition-release process and subsequent structural changes in the pore helices. These findings provide mechanistic insights into the activation mechanism of SLAC1 and shed light on understanding how SLAC1 controls stomatal closure in response to environmental stimuli.

Lactylation of histone by BRD4 regulates astrocyte polarization after experimental subarachnoid hemorrhage.

Under subarachnoid hemorrhage (SAH) conditions, astrocytes undergo a marked intensification of glycolytic activity, resulting in the generation of substantial amounts of lactate to maintain the energy demand for neurons and other brain cells. Lactate has garnered increasing attention in recent years because of its emerging role in critical biological processes such as inflammation regulation and neuroprotection, particularly through its histone lactylation. Bromodomain-containing protein 4 (BRD4) plays a crucial role in maintaining neural development and promoting memory formation in the central nervous system. Nonetheless, the function and regulatory mechanism of BRD4 and histone lactylation in astrocytes following SAH remain elusive. Our findings indicate that BRD4, a crucial epigenetic regulator, plays a definitive role in histone lactylation. Both in vitro and in vivo, these results demonstrated that targeted silencing of BRD4 in astrocytes can significantly reduce H4K8la lactylation, thereby aggravating the A1 polarization of astrocytes and ultimately affecting the recovery of neural function and prognosis in mice after SAH. In summary, BRD4 plays a pivotal role in modulating astrocyte polarization following SAH via histone lactylation. Targeting this mechanism might offer an efficient therapeutic strategy for SAH.

Thiol-ene Click Chemistry Synthesis of L-Cysteine-Grafted Graphene Oxide As a New Corrosion Inhibitor for Q235 Steel in Acidic Environment.

l-cysteine, as an eco-friendly and nontoxic corrosion inhibitor, was directly covalently linked to the carbon/carbon double bonds of the GO flakes by a thiol-ene click reaction to avoid decreasing the number of hydrophilic oxygen-containing polar functionalities. The corrosion inhibition performances of Cys-GO toward Q235 steel (QS) in diluted hydrochloric acid were studied by electrochemical methods. The corrosion was a charge transfer-controlled process, and Cys-GO manifested as a mixed-type corrosion inhibitor. The corrosion inhibition efficiency (η) for QS showed a first-increase-and-then-decrease trend with increasing Cys-GO concentrations. The optimum concentration of Cys-GO was 15 mg L-1, and the according η value was up to 90%. The Cys-GO adsorbed on the QS surface to form a protective barrier was responsible for the efficient corrosion inhibition. Langmuir adsorption isotherm model was fitted well with the experiment data, indicating a monolayer adsorption. Furthermore, the coordinate covalent bonds, π-back-donation effect, and electrostatic attraction were responsible for the Cys-GO adsorption on the QS surface.

The threaten of typhoons to the health of residents in inland areas: a study on the vulnerability of residents to death risk during typhoon "Lekima" : In Jinan, China.

BACKGROUND: Studies had suggested increased risk of death of residents was associated with typhoons, particularly coastal regions. However, these findings ignored the impact of inland typhoons on the health of residents, especially the indirect death risk caused by typhoons. This study aimed to investigate the acute death risk of residents during inland typhoon Lekima in Jinan, further identify vulnerable populations and areas. METHODS: We selected the daily death from 11 to 27th August 2019 in Jinan as case period, and conducted a time-stratified case-crossover design to match the contemporaneous data from 2016 to 2018 as control period. We used the generalized linear Poisson models to estimate the related effects of death risk during typhoon Lekima and lag days. RESULTS: During the Lekima typhoon month, there were 3,366 deaths occurred in Jinan. Compared to unexposed periods, the acute death risk of non-accidental diseases (especially circulatory diseases), female and the older adults increased significantly in the second week after the typhoon. The maximum significant effect of circulatory disease deaths, female and older adult deaths were appeared on lag9, lag9, and lag13 respectively. And the typhoon-associated RR were 1.19 (95%CI:1.05,1.34), 1.28 (95%CI:1.08,1.52), and 1.22 (95%CI:1.06,1.42) respectively. The acute death risk of residents living in TQ and CQ increased significantly on Lag2 and Lag6 after the typhoon, respectively, while those living in LX, LC, HY, JY, and SH occurred from Lag 8 to Lag 13 after the typhoon. LC lasted the longest days. CONCLUSIONS: Typhoons would increase the vulnerability of residents living in Jinan which mainly occurred from the seventh day after the typhoon. Residents suffering from non-accidental diseases (circulatory diseases), female and the older adults were more vulnerable. The vulnerability of TQ and CQ occurred on Lag2 and Lag6 after typhoon Lekima, respectively, and the other areas except ZQ and PY occurred from Lag 8 to Lag 13. LC lasted the longest duration. Our findings emphasized the importance of the emergency response, which would help policymakers to identify vulnerable regions and populations accurately during typhoons and formulate the emergency response plan.

Ultrasonic-Assisted Marine Antifouling Strategy on Gel-like Epoxy Primer.

Ultrasonic technology has drawn extensive interests for its great potential in marine antifouling applications. However, its effects on the adhesion behavior of marine fouling organisms on marine structures remain underexplored. This work investigated how ultrasonic treatment impacted the adhesion of Pseudoalteromonas on a gel-like marine epoxy primer. And the process parameters for ultrasonic treatment were optimized using response surface analysis with Design-Expert software 11. The results revealed that ultrasonic treatment disrupted the cellular structure of Pseudoalteromonas, causing the deformation and fragmentation of the cell membrane, leading to bacterial death. Additionally, ultrasonic treatment reduced the particle size and Zeta potential value of Pseudoalteromonas, which disrupted the stability of bacterial suspensions. It also increased the relative surface hydrophobicity of Pseudoalteromonas cells, resulting in a reduction in adhesion to the gel-like marine epoxy primer. This study demonstrated that ultrasonic treatment significantly disturbed the adhesion behavior of microorganisms like Pseudoalteromonas on the gel-like marine epoxy primer, which provided an effective approach for controlling marine biofouling.

Different doses of methimazole treatment of children and adolescents with graves' disease: a clinical study based on 161 cases of outpatients.

OBJECTIVE: This study aimed to evaluate the association between the initial dose of MMI and the clinical course, as well as adverse effects on young people with GD. METHODS: One hundred and sixty-one children and adolescents with newly diagnosed GD were enrolled for this study and categorized into four groups based on initial serum-free T3 and T4 levels and daily MMI doses: Group A (mild, 0.3-0.5 mg/kg/day, n = 78), Group B (moderate, 0.6-0.8 mg/kg/day, n = 37), Group C (severe, 0.6-0.8 mg/kg/day, n = 24), and Group D (severe, 0.8-1.0 mg/kg/day, n = 22). The thyroid function, blood cell analysis and liver function were examined before treatment and at 4, 8 and 12 weeks after treatment. Outcome of long-term follow-up were also observed. RESULTS: After 12 weeks of treatment, 91.0% of the patients in group A and 90.9% of the patients in group D recovered to normalization of FT3, which was slightly higher than the other two groups; 70.8% of the patients in group C recovered to normalization of FT4, which was slightly lower than that in the other three groups. The incidence of minor adverse effects was 12.8% in group A, 13.5% in group B, 16.7% in group C and 40.9% in group D (P < 0.01). Remission was achieved in 38 patients (23.6%). CONCLUSIONS: Lower doses of MMI (0.3-0.5 mg/kg/day) are suitable for mild GD, and higher doses of MMI (0.6-0.8 mg/kg/day) are advisable for moderate or severe GD. Much higher doses of MMI (0.8-1.0 mg/kg/day) are harmful for initial use in children and adolescents with GD patients.

Role of inner solvation sheath within salt-solvent complexes in tailoring electrode/electrolyte interphases for lithium metal batteries.

Functional electrolyte is the key to stabilize the highly reductive lithium (Li) metal anode and the high-voltage cathode for long-life, high-energy-density rechargeable Li metal batteries (LMBs). However, fundamental mechanisms on the interactions between reactive electrodes and electrolytes are still not well understood. Recently localized high-concentration electrolytes (LHCEs) are emerging as a promising electrolyte design strategy for LMBs. Here, we use LHCEs as an ideal platform to investigate the fundamental correlation between the reactive characteristics of the inner solvation sheath on electrode surfaces due to their unique solvation structures. The effects of a series of LHCEs with model electrolyte solvents (carbonate, sulfone, phosphate, and ether) on the stability of high-voltage LMBs are systematically studied. The stabilities of electrodes in different LHCEs indicate the intrinsic synergistic effects between the salt and the solvent when they coexist on electrode surfaces. Experimental and theoretical analyses reveal an intriguing general rule that the strong interactions between the salt and the solvent in the inner solvation sheath promote their intermolecular proton/charge transfer reactions, which dictates the properties of the electrode/electrolyte interphases and thus the battery performances.

Sustainable treatment of sewage sludge via plasma-electrolytic liquefaction for bio-friendly production of polyurethane foam.

Safe and green disposal or utilization of sewage sludge (SS) has attracted significant attention as SS is increasingly produced worldwide and emerges as an environmental burden if without proper treatment. In this study, efficient and sustainable treatment of SS was achieved using plasma-electrolytic liquefaction (PEL) with alkaline catalysts including sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and sodium acetate (NaAc) and renewable solvents including polyethylene glycol (PEG) 200 and glycerol. Furthermore, the obtained bio-oil with abundant hydroxyl groups could partially replace polyols derived from fossil energy to synthesize bio-based polyurethane foams (BPUFs) for oil adsorption. The results showed that the Na2CO3 catalyst exhibited better performance and yielded bio-oil with a higher heating value (HHV) of 26.26 MJ/kg, very low nitrogen content (0.14%) and metal ions, and a nearly neutral pH of 7.41, under the optimized conditions. Compared with conventional oil bath liquefaction, PEL can significantly improve the liquefaction efficiency, promote the transfer of metal ions in SS to the solid residue (SR), and facilitate the transfer of nitrogen to the gas phase and SR, thereby upgrading the bio-oil to a certain extent. The BPUFs showed excellent oil adsorption capacity, reusability, and desorption and can play an important role in combating oil spills. The PEL method may provide a green avenue for SS valorization and the comprehensive utilization of the obtained products.

Fecal Calprotectin in Children with Cow's Milk Protein Allergy: A Systematic Review and Meta-Analysis.

OBJECTIVE: There is still an unmet need for a reliable and straightforward biomarker to diagnose and monitor cow's milk protein allergy (CMPA). Fecal calprotectin (FC) has been reported as a biomarker for CMPA. Therefore, the meta-analysis aimed to evaluate the value of FC in the diagnosis and monitoring of CMPA. METHODS: PubMed, EMBASE, and the Cochrane Library up to April 2022 were searched for relevant studies. Pooled standardized mean difference (SMD) and 95% confidence intervals (CIs) were determined using the forest plot. Heterogeneity was used to determine the fixed or random-effect model. RESULTS: Twelve studies including 310 patients and 217 controls were available for the meta-analysis. The FC levels in children with CMPA were significantly higher than in healthy control (SMD = 1.15; 95% CI: 0.38-1.91). After elimination diet treatment, FC levels were reduced considerably with the pooled SMD of 0.87 (95% CI: 0.48-1.26). CONCLUSION: The results indicated that FC could be a simple and reliable biomarker for diagnosing CMPA, especially in non-IgE-mediated CMPA infants. Besides, calprotectin was also potential for predicting therapy response of CMPA.

Assessment of the Ovarian Reserve by Serum Anti-Müllerian Hormone in Rheumatoid Arthritis Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: The ovarian reserve has been reported to be diminished in patients with rheumatoid arthritis. However, these results are still controversial. Anti-Müllerian hormone (AMH) is considered a reliable biomarker for the ovarian reserve. We thus performed a meta-analysis to evaluate the AMH levels and the effect of DMARDs on the ovarian reserve in rheumatoid arthritis patients. METHODS: PubMed, EMBASE, the Cochrane Library, and 2 Chinese databases (CNKI and Wanfang database), up to September 2021, were searched for relevant studies. The Newcastle-Ottawa scale (NOS) was used to assess the quality of the included studies. Pooled standard mean difference (SMD) with 95% confidence intervals (CIs) were determined with the random-effects model. The heterogeneity was described by I2 statistic and p value from the Cochrane Q test. RESULTS: Eight eligible studies (679 patients and 1,460 controls) were included in the meta-analysis. Compared with healthy control, the AMH levels in RA patients were significantly lower with the pooled SMD of -0.40 (95% CI: -0.66 to -0.14). However, in comparison of AMH with and without DMARD treatment, there was no significant difference with the pooled SMD of -0.1 (95% CI: -0.39 to 0.19). CONCLUSION: The results indicated that there was an increased risk of ovarian failure in RA patients and which is not related to DMARD treatment.

Extreme cold weather and circulatory diseases of older adults: A time-stratified case-crossover study in jinan, China.

OBJECTIVES: We aimed to investigate the acute effect of extreme cold weather on circulatory disease mortality of older adults in Jinan, with individual and regional-scale characteristics as subgroup analyses to further identify vulnerable populations. METHODS: This study contained the death data of Jinan from 2011 to 2020 (Nov-Mar). A time-stratified case-crossover method was used to estimate the effects of extreme cold weather and lags 0-8 days, controlling for holiday and relative humidity. To evaluate the impact of different durations and thresholds of extreme cold weather, we considered 4 cold day and 12 cold wave definitions RESULTS: Our results showed an increase in circulatory disease deaths under several definitions. The number of older adults died of circulatory diseases totaled 92,119 during the study period. In the definitions of cold day, the maximum significant effect ranging from 1.08 (95% CI: 1.03,1.14) to 1.13 (95% CI: 1.04,1.24) and appeared on Lag5 or Lag6. In the definitions of cold wave, the maximum significant effect ranging from 1.07 (95% CI: 1.02, 1.12) to 1.14 (95% CI: 1.03, 1.25). The cold effect is mainly attributable to cold day rather than an added effect related to the duration. Our research confirmed that extreme cold weather had a stronger impact on women [maximum effects with an OR of 1.21 (95% CI: 1.08, 1.36) in P1, 1.19 (95% CI: 1.05, 1.36) in M12)], and the effect gradient increased with age. CONCLUSIONS: Our findings support the evidence on the impact of extreme cold weather on circulatory disease mortality and provide a basis for policymakers to select target groups to develop policies and reduce the public health burden.

A model for the uptake of advance care planning in older cancer adults: a scoping review.

BACKGROUND AND AIMS: Advance care planning (ACP) might assist older cancer patients in expressing their goals, values, and care preferences; yet, the ACP uptake rates in this group are low. The goal of this study is to discover factors that influence ACP uptake in older cancer adults and to construct a model that integrates these factors. METHODS: Using Arksey and O' Malley's methodology, we systematically searched seven electronic databases of ACP literature in older cancer adults from inception to March 2022. To identify factors linked to ACP uptake in elderly cancer patients, researchers used a pre-piloted extraction form. There were two phases to the thematic analysis of the labeled factors. First, factors were grouped into one of three categories using a directed content analysis approach: patient context, provider context, or mechanism. Second, we took both a deductive and inductive thematic approach to identifying and coding contributing factors in each category to identify themes and subthemes. Deductive coding was undertaken using the Andersen's Behavioral Model of Health Services Utilization. Finally, results were visualized into a conceptual model. RESULTS: In the including 37 articles, 131 factors were extracted. Thematic analysis of patient context factors (n = 72) showed that ACP uptake in older cancer adults is associated with predisposing characteristics, enabling resources and need. Factors attributed to provider context (n = 28) concerned predisposing characteristics and enabling resources. Mechanism factors (n = 31) are related to perceived value and patient trust, and the C-ACP uptake model was created. CONCLUSION: ACP uptake in older cancer patients is commonly influenced by patient-provider-related contextual factors, and highlights the fact that ACP uptake is more likely to be mediated through both perceived value and patient trust. This review serves as a resource for providers exploring ACP implementation options in older cancer adults.

The subjective experience of family caregivers of people living with Parkinson's disease: a meta-ethnography of qualitative literature.

BACKGROUND AND AIMS: Parkinson's disease patients (PwPD) rely heavily on their family caregivers. However, there remains uncertainty regarding the subjective experience of the family caregivers of PwPD. This study aims to provide an in-depth summary of the current knowledge about the subjective experiences of family caregivers caring for PwPD, to understand the factors that influence this experience and to provide the evidence for healthcare services. METHODS: We conducted a systematic review and meta-ethnography using Noblit and Hare's approach. The search strategy used MeSH terms in combination with free-text searching of 10 databases (from their inception until July 2021). Titles and abstracts were reviewed by two reviewers and, for the studies that met the eligibility criteria, full-text articles were obtained. The Critical Appraisal Skills Program (CASP) checklist was employed to assess the quality of studies. RESULTS: A total of 3318 studies were screened and 29 qualitative studies were included in this review. These studies recorded the experience of 399 participants across 12 countries, most were females. Five themes emerged: (a) feelings related to PD; (b) challenges to family life; (c) external challenges; (d) adjustment and adaptation; (e) external support. We propose a new conceptual model that highlights that the experiences of caregivers for PwPD are dynamic and influenced by a variety of internal and external factors. CONCLUSION: Our findings illustrate the complex and dynamic experiences of family caregivers for PwPD. It is necessary to explore how the influencing factors can be modified to improve the lived experience of family caregivers.

Ponesimod protects against neuronal death by suppressing the activation of A1 astrocytes in early brain injury after experimental subarachnoid hemorrhage.

As an important initiator and responder of brain inflammation in the central nervous system (CNS), astrocytes transform into two new reactive phenotypes with changed morphology, altered gene expression and secretion profiles, termed detrimental A1 and beneficial A2. Inflammatory events have been shown to occur during the phase of early brain injury (EBI) after subarachnoid hemorrhage (SAH). However, the phenotype transformation of astrocytes as well as its potential contribution to inflammatory status in the EBI of SAH has yet to be determined. In the present study, both in vivo and in vitro models of SAH were established, and the polarization of astrocytes after SAH was analyzed by RNA-seq, western blotting, and immunofluorescence staining. The effect of astrocytic phenotype transformation on neuroinflammation was examined by real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). We demonstrated that astrocytes were transformed into A1 astrocytes and caused neuronal death through the release of pro-inflammatory factors in EBI after SAH. Importantly, Ponesimod, an S1PR1 specific modulator, exerted neuroprotective effects through the prevention of astrocytic polarization to the A1 phenotype as proved by immunofluorescence, neurological tests, and TUNEL study. We also revealed the role of Ponesimod in modulating astrocytic response was mediated by the signal transducer and activator of transcription 3 (STAT3) signaling. Our study suggested that Ponesimod may be a promising therapeutic target for the treatment of brain injury following SAH.

Investigation of Allergic Sensitization Pattern in 4,203 Children in Northern China.

OBJECTIVE: The objective of this study is to investigate the allergen sensitization pattern among 4,203 children in the Shanxi region of China and to provide guidance for diagnosis and prevention of allergic diseases. METHODS: A retrospective analysis was conducted on the allergen-specific immunoglobulin E (sIgE) results of 4,203 children aged 0-12 years from January to December in 2019. SIgE antibodies to 19 allergens in the serum sample were detected by enzyme ALLERGO-SORBENT testing. RESULTS: In total, 49.70% (2,089/4,203) of children with allergic diseases were positive for sIgE, and the top 5 allergens were egg white 18.63% (783/4,203), artemisia 14.47% (608/4,203), milk 13.04% (548/4,203), ragweed 8.66% (364/4,203), and poplar/willow/elm 8.52% (358/4,203). Significant differences in the positive rate of food allergens and aeroallergens in different ages were found (p < 0.05). 50.98% (1,065/2,089) patients were sensitive to 2 or more allergens. The high sensitization rate in the >3-year group was significantly higher than the ≤3-year group (p < 0.05). CONCLUSION: Egg white and artemisia are the most common allergens in children in northern China. This study provides allergic sensitization pattern of children and clinical epidemiological data in the region.

Dynamic Metal Exchange between a Metalloid Silver Cluster and Silver(I) Thiolate.

Although a homometallic (isotopic metal) exchange reaction has been reported, the in-depth understanding of the interaction between a metalloid cluster and the homometal (representing the same metal element as the metalloid cluster) thiolate is quite limited, especially at the atomic level. Herein, based on Ag44(SR)30 (where SR represents 4-mercaptobenzoic acid), we report a facile approach for investigating the metalloid cluster-homometal thiolate interaction at the atomic level, i.e., isotopic exchange in the Ag metalloid cluster. Since such a reaction takes no account of the enthalpy change-related heterometal (representing a different metal element) exchange, the intrinsic metalloid cluster-homometal thiolate interaction can be thoroughly investigated. Through analyzing the ESI-MS (electrospray ionization mass spectrometry) and MS/MS (mass/mass spectrometry) results of the reversible conversion between 107Ag44(SR)30 and 109Ag44(SR)30, we observed that all Ag atoms are exchangeable in the Ag44(SR)30 template. In addition, through analyzing the ESI-MS results of the interconversion between 107Ag29(BDT)12(TPP)4 and 109Ag29(BDT)12(TPP)4, we demonstrated that the metal exchange in the Ag29(BDT)12(TPP)4 metalloid cluster should be a shell → kernel metal transfer process. Our results provide new insights into the metalloid cluster reactivity in the homometal thiolate environment, which will guide the future preparation of metalloid clusters with customized structures and properties.

Selection and identification of an ssDNA aptamer to NB4 cell.

This study was to find the aptamers with high affinity and specificity binding to acute promyelocytic leukemia (APL) NB4 cell line. These aptamers targeted NB4 cells were selected from a random single-stranded DNA (ssDNA) library of systematic evolution of ligands by exponential enrichment (CELL-SELEX). The binding rate of FITC-ssDNA library and NB4 cells was monitored using flow cytometry and fluorescence microscope. After cloned and sequenced, the structure, specificity, and affinity of these candidate aptamers were further analyzed. After a total of 19 rounds of selection, the ssDNA library was enriched and the BR (19.9%) of the 16th round was 12 times of the first round (1.6%). Three enriched aptamers were obtained from 21 positive clones of the 16th round, and the predicted secondary structures of these aptamers were mainly stem-loop. The aptamer CX9 had the highest affinity, and the equilibrium dissociation constant (Kd) was 16.2 nM. The fluorescence intensity of CX9 binding to NB4 cells was stronger than HL60 and K562 cells under fluorescence microscopy. The study indicates that aptamer CX9 exhibits high affinity and specificity with NB4 cells and lay a foundation for the rapid diagnostic method to detect APL with fluorescence-labeled aptamer.

Advanced Low-Flammable Electrolytes for Stable Operation of High-Voltage Lithium-Ion Batteries.

Despite being an effective flame retardant, trimethyl phosphate (TMPa ) is generally considered as an unqualified solvent for fabricating electrolytes used in graphite (Gr)-based lithium-ion batteries as it readily leads to Gr exfoliation and cell failure. In this work, by adopting the unique solvation structure of localized high-concentration electrolyte (LHCE) to TMPa and tuning the composition of the solvation sheaths via electrolyte additives, excellent electrochemical performance can be achieved with TMPa -based electrolytes in Gr∥LiNi0.8 Mn0.1 Co0.1 O2 cells. After 500 charge/discharge cycles within the voltage range of 2.5-4.4 V, the batteries containing the TMPa -based LHCE with a proper additive can achieve a capacity retention of 85.4 %, being significantly higher than cells using a LiPF6 -organocarbonates baseline electrolyte (75.2 %). Meanwhile, due to the flame retarding effect of TMPa , TMPa -based LHCEs exhibit significantly reduced flammability compared with the conventional LiPF6 -organocarbonates electrolyte.

Optimization of Magnesium-Doped Lithium Metal Anode for High Performance Lithium Metal Batteries through Modeling and Experiment.

Lithium (Li)-magnesium (Mg) alloy with limited Mg amount, which can also be called Mg-doped Li (Li-Mg), has been considered as a potential alternative anode for high energy density rechargeable Li metal batteries. However, the optimum doping-content of Mg in Li-Mg anode and the mechanism of the improved performance are not well understood. Herein, density functional theory (DFT) calculations are used to investigate the effect of Mg amount in Li-Mg anode. The Li-Mg with about 5 wt. % Mg (abbreviated as Li-Mg5) has the lowest absorption energy of Li, thus all the surface area can be "controlled" by Mg atoms, leading to the smooth and continuous deposition of Li on the surface around the Mg center. A localized high concentration electrolyte enables Li-Mg5 to exhibit the best cycling stability in Li metal batteries with high-loading cathode and lean electrolyte under 4.4 V high-voltage, which is approaching the demand of practical application. This electrolyte also helps generate an inorganic-rich solid electrolyte interphase, which leads to smooth, compact and less corrosion layer on the Li-Mg5 surface. Both theoretical simulations and experimental results prove that Li-Mg5 has optimum Mg content and gives best battery cycling performance.

Peroxo Species Formed in the Bulk of Silicate Cathodes.

Oxygen redox in Li-rich oxides may boost the energy density of lithium-ion batteries by incorporating oxygen chemistry in solid cathodes. However, oxygen redox in the bulk usually entangles with voltage hysteresis and oxygen release, resulting in a prolonged controversy in literature on oxygen transformation. Here, we report spectroscopic evidence of peroxo species formed and confined in silicate cathodes amid oxygen redox at high voltage, accompanied by Co2+ /Co3+ redox dominant at low voltage. First-principles calculations reveal that localized electrons on dangling oxygen drive the O-O dimerization. The covalence between the binding cation and the O-O dimer determines the degree of electron transfer in oxygen transformation. Dimerization induces irreversible structural distortion and slow kinetics. But peroxo formation can minimize the voltage drop and volume expansion in cumulative cationic and anionic redox. These findings offer insights into oxygen redox in the bulk for the rational design of high-energy-density cathodes.