Revealing the Mechano-Electrochemical Coupling Behavior and Discharge Mechanism of Fluorinated Carbon Cathodes toward High-Power Lithium Primary Batteries.

Unclear reaction mechanisms and unsatisfactory power performance hinder the further development of advanced lithium/fluorinated carbon (Li/CFx ) batteries. Herein, the mechano-electrochemical coupling behavior of a CFx cathode is investigated by in situ monitoring strain/stress using digital image correlation (DIC) techniques, electrochemical methods, and theoretical equations. The DIC monitoring results present the distribution and dynamic evolution of the plane strain and indicate strong dependence toward the material structure and discharge rate. The average plane principal strain of fully discharged 2D fluorinated graphene nanosheets (FGNSs) at 0.5 C is 0.50%, which is only 38.5% that of conventional bulk-structure CFx . Furthermore, the superior structural stability of the FGNSs is demonstrated by the microstructure and component characterization before and after discharge. The plane stress evolution is calculated based on theoretical equations, and the contributions of electrochemical and mechanical factors are examined and discussed. Subsequently, a structure-dependent three-region discharge mechanism for CFx electrodes is proposed from a mechanical perspective. Additionally, the surface deformation of Li/FGNSs pouch cells formed during the discharge process is monitored using in situ DIC. This study reveals the discharge mechanism of Li/CFx batteries and facilitates the design of advanced CFx materials.

Accordion-Like Fluorinated Graphite Nanosheets with High Power and Energy Densities for Wide-Temperature, Long Shelf-Life Sodium/Potassium Primary Batteries.

Sodium and potassium are considered to be the most promising anode candidates due to their easy availability, low-cost and similar chemical properties to lithium. Here, novel 3D accordion-like fluorinated graphite nanosheets (FGNSs) are reported as cathodes for sodium primary batteries (SPBs) and potassium primary batteries (PPBs). The FGNSs-x cathode exhibits unprecedented power and energy density due to the impressive 3D structure, high F/C ratio (1.0), and more surface CC bonds (7.14%). The FGNSs-1.0 exhibits very high specific capacities of 831.3 and 834.1 mAh g-1 for SPBs and PPBs, respectively, close to the theoretical capacity. Besides, the maximum energy density of FGNSs-1.0 in SPBs and PPBs are 1960.5 and 2144.6 Wh kg-1 , respectively. The maximum power density for Na/CFx and K/CFx batteries could reach up to 7076.8 and 6227.4 W kg-1 , respectively. The electrochemical performance of FGNSs-1.0 at extreme temperatures (-30 to 100 °C), long storage time (60 days), high mass loading (3.6 mg cm-2 ), and pouch-type cell is also evaluated for the first time. Surprisingly, FGNSs-1.0 has outstanding performance in these projects. Therefore, the new-type Na/CFx and K/CFx primary battery systems developed here have broad application prospects in high-energy applications that require high-power, low-cost, and normal use under extreme conditions.

Surface-coated AlF3 nanolayers enable polysulfide confinement within biomass-derived nitrogen-doped hierarchical porous carbon microspheres for improved lithium-sulfur batteries.

The electrically insulating and volumetric deformation of sulfur and the shuttle effect of the intermediate lithium polysulfide (LiPSs) have severely hindered the development of lithium-sulfur batteries (LSBs). Herein, a synergistic strategy of hierarchical porous nitrogen-doped carbon microspheres (PNCM) derived from low-cost biomass with surface-coated AlF3 nanolayer as a multifunctional sulfur host (denoted as PNCM@S@AlF3) was developed. The PNCM not only possesses an abundant pore structure, large surface area, and high electrical conductivity but also features an intrinsic N-doped and fluorinated framework, which effectively enhances the physical adsorption and chemical anchoring to LiPSs. In addition, the AlF3 nanolayer protects the open surface of the porous carbon to isolate sulfur species from the electrolyte to reduce irreversible losses while accelerating the redox kinetics of LiPSs through strong polar adsorption and bonding. Hence, the PNCM@S@AlF3 cathode exhibits an initial capacity as high as 1176.2 mAh/g at 0.2C, and the cycling stability and rate capability are superior to that of PNCM@S without AlF3 coating. Impressively, the PNCM@S@AlF3 cathode delivers stable long-term cycling performance at a high rate of 2C, with 95.6% capacity retention after 500 cycles. This work presents a facile, sustainable, and efficient synergistic strategy for developing advanced LSBs.

Surface Engineering of Fluorinated Graphene Nanosheets Enables Ultrafast Lithium/Sodium/Potassium Primary Batteries.

Fluorinated carbon (CFx ) is considered as a promising cathode material for lithium/sodium/potassium primary batteries with superior theoretical energy density. However, achieving high energy and power densities simultaneously remains a considerable challenge due to the strong covalency of the C-F bond in the highly fluorinated CFx . Herein, an efficient surface engineering strategy combining surface defluorination and nitrogen doping enables fluorinated graphene nanosheets (DFG-N) to possess controllable conductive nanolayers and reasonably regulated C-F bonds. The DFG-N delivers an unprecedented dual performance for lithium primary batteries with a power density of 77456 W kg-1 and an energy density of 1067 Wh kg-1 at an ultrafast rate of 50 C, which is the highest level reported to date. The DFG-N also achieves a record power density of 15 256 and 17 881 W kg-1 at 10 C for sodium and potassium primary batteries, respectively. The characterization results and density functional theory calculations demonstrate that the excellent performance of DFG-N is attributed to surface engineering strategies that remarkably improve electronic and ionic conductivity without sacrificing the high fluorine content. This work provides a compelling strategy for developing advanced ultrafast primary batteries that combine ultrahigh energy density and power density.

An eleven autophagy-related genes-based prognostic signature for endometrial carcinoma.

BACKGROUND: Endometrial cancer (EC) is a common malignant tumor in women with increasing mortality. The prognosis of EC is highly heterogeneous which needs more effective biomarkers for clinical decision. Here, we reported the effect of autophagy-related genes (ARGs) on the prognosis of EC. METHODS: The expression data of EC tissues and adjacent non-tumor samples were available from the TCGA dataset and 232 autophagy-related genes were from The Human Autophagy Database. A prognostic ARGs risk model was further constructed by using LASSO-Cox regression, and its prognostic and predictive value were evaluated by nomogram. Further functional analysis was conducted to reveal a significant signaling pathway. RESULTS: A total of 45 differentially expressed ARGs were obtained, including 18 upregulated and 27 downregulated genes. Eleven ARGs (BID, CAPN2, CDKN2A, DLC1, GRID2, IFNG, MYC, NRG3, P4HB, PTK6, and TP73) were finally selected to build ARGs risk. This signature could well distinguish between the high- and low-risk patients (survival analysis: P = 1.18E-10; AUC: 0.733 at 1 year, 0.795 at 3 years, and 0.823 at 5 years). Furthermore, a nomogram was plotting to predict the possibility of overall survival and suggested good value for clinical utility. CONCLUSION: We established an eleven-ARG signature, which was probably effective in the prognostic prediction of patients with EC.

Ultrafast Li/Fluorinated Graphene Primary Batteries with High Energy Density and Power Density.

Lithium/fluorinated carbon (Li/CFx) primary batteries have essential applications in consumer electronics and medical and high-power military devices. However, their application is limited due to the difficulty in achieving simultaneous high power density and high energy density in the CFx cathode. The tradeoff between conductivity and fluorine content is the decisive factor. Herein, by rational design, 3D porous fluorinated graphene microspheres (FGS-x) with both high conductivity and a high F/C ratio are successfully synthesized for the first time. FGS-x possesses an F/C ratio as high as 1.03, a nanosheet structure with hierarchical pores, abundant C═C bonds, few inactive C-F2 bonds, and electrochemically active C-F bonds. The beneficial features that can increase discharge capacity, shorten the diffusion length for both ions and electrons, enhance the Li+ intercalation kinetics, and accommodate the volume change are demonstrated. The Li/FGS-1.03 coin cell delivers an unprecedented power density of 71,180.9 W/kg at an ultrahigh rate of 50 C (43.25 A/g), coupled with a high energy density of 830.7 Wh/kg. Remarkably, the Li/FGS-1.03 pouch cell exhibits a record cell-level power density of 12,451.2 W/kg at 20 C. The in-depth investigation by the ex situ method on structural evolution at different discharge depths reveals that the excellent performance benefits from the structural stability and the uniform formation of LiF. The FGS-1.03 cathode also has excellent performance in extreme operating temperatures (0 to 100 °C) and high active material mass loading (4.3 mg/cm2). These results indicate that the engineered fluorinated graphene developed here has great potential in applications requiring both high power density and high energy density.

Immediate and short-term effects of transcatheter device closure of large atrial septal defect in senior people.

OBJECTIVES: We sought to evaluate the safety and efficacy in improving cardiac function and functional capacity with device closure of large atrial septal defects (ASD) in senior adults. BACKGROUND: Atrial septal defect accounts for about 10% of all congenital heart disease. It still remains unclear whether large ASD closure in senior people should be performed or not. Hence we aim to prospectively assess the safety and clinical status of senior patients after transcatheter closure in large ASD. PATIENTS AND INTERVENTIONS: This was a prospective study of all patients aged over 50 years who underwent device closure of a secundum large ASD between January 2013 and January 2018. Investigations including brain natriuretic peptide level, electrocardiography, chest X-ray, transthoracic echocardiogram, transesophageal echocardiogram, and 6-minute walk test were performed before and at 2 days and 4 weeks and 6 months after the procedure. RESULTS: Twenty patients (median age 68 years, 10 women) had transcatheter device closure of large ASD successfully. Median ASD size was 32 mm (range 30-39 mm). Median pulmonary artery pressure was 58 mm Hg (range 47-67 mm Hg). At 6 months, there was a significant change in right atrium size (P < .001) and right ventricle size (P < .01) and left ventricle size (P < .001) and also pulmonary artery pressure (P < .0001), New York Heart Association functional class improved (P = .03) in 19 patients and also significant improvement in 6-minute walk test distance (P < .001). There were no major complications. CONCLUSIONS: Our data showed that large ASD closure at senior people results in satisfactory cardiac remodeling and cardiac function improvement.

Sepiolite/CNT/S@PANI composite with stable network structure for high performance lithium sulfur batteries.

Composite materials with a stable network structure consisting of natural sepiolite (Sep) powders, carbon nanotubes (CNTs) and conductive polymer (PANI) have been successfully synthesized using a simple vacuum heat treatment and chemical oxidation method, and they have been used as cathode materials for lithium sulfur batteries. It is found that Sep/CNT/S@PANI composites possess high initial discharge capacity, good cyclic stability and good rate performance. The initial discharge capacity of the Sep/CNT/S@PANI-II composite is about 1100 mA h g-1 at 2C, and remained at 650 mA h g-1 after 300 cycles, and the corresponding coulombic efficiency is above 93%. Such performance is attributed to specific porous structure, outstanding adsorption characteristics, and excellent ion exchange capability of sepiolite, as well as excellent conductivity of CNT. Furthermore, the PANI coating has a pinning effect for sulfur, which enhances the utilization of the active mass and improves the cycling stability and the coulombic efficiency of the composites at high current rates.