RESUMO
Vanadium oxide (V2O3) has been considered as a promising anode material for potassium-ion batteries (PIBs), but challenging as well for the low electron/ion conductivity and poor structural stability. To tackle these issues, herein, a novel sheetlike hybrid nanoarchitecture constructed by uniformly encapsulating V2O3 nanoparticles in amorphous carbon nanosheets (V2O3@C) with the generation of C-O-V bonding is presented. Such a subtle architecture effectively facilitates the infiltration of electrolyte, relieves the mechanical strain, and reduces the potassium-ion diffusion distance during the repetitive charging/discharging processes. The generated C-O-V bonding not only accelerated charge transfer across the carbon-V2O3 interface but also strengthened the structural stability. Benefiting from the synergistic effects, the as-prepared V2O3@C nanosheets display fast and durable potassium storage behaviors with a reversible capacity of 116.6 mAh g-1 delivered at 5 A g-1, and a specific capacity of 147.9 mAh g-1 retained after 1800 cycles at a high current density of 2 A g-1. Moreover, the insertion/extraction mechanism of V2O3@C nanosheets in potassium-ion storage is systematically demonstrated by electrochemical analysis and ex situ technologies. This study will shed light on the fabricating of other metal oxides anodes for high-performance PIBs and beyond.
RESUMO
Na4MnV(PO4)3 (denoted as NMVP) has drawn increasing attention owing to the three-dimensional framework and high theoretical capacity. Nevertheless, the inherent low electronic conductivity of NMVP impedes the scale-up commercial applications. In this work, the feasibility to achieve ultrahigh-rate capability and long lifespan by in situ embedding the intertwined carbon nanotube (CNT) matrix into the bulk of Na4MnV(PO4)3@C composites through a facile wet-chemical approach is reported. The elaborately prepared Na4MnV(PO4)3@C@CNTs cathode delivers a discharge capacity of 109.9 mA h g-1 at C/5 with an impressive rate capability of 68.9 mA h g-1 at an ultrahigh current rate of 90 C as well as a fascinating cycling performance of 68.3% capacity retention at 40 C after 4000 cycles. The optimum design of the 3D well-interconnected NMVP permitting fast kinetics for transported Na+/e- is beneficial to the excellent electrochemical performance, which is further studied by the galvanostatic intermittent titration technique, cyclic voltammetry, and electrochemical impedance spectra measurements. The pseudocapacitance contributions are also investigated. The research demonstrates that the dual-nanocarbon synergistically modified NMVP composite is expected to facilitate the commercialization of sodium-ion batteries.
RESUMO
BACKGROUND: Associations between cytotoxic T lymphocyte antigen-4 (CTLA-4) +49A/G polymorphism and cancer risk are inconclusive. We performed this meta-analysis to derive a more precise estimation of the relationship. METHODS: A comprehensive literature search was performed using electronic databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. RESULTS: A total of 16,358 cases and 19,737 controls from 46 studies were included. Overall, significant association between CTLA-4 +49A/G polymorphism and cancer risk was observed in all genetic models (G vs. A: OR=0.88, 95%CI=0.83-0.93, PH=0.000; GA vs. AA: OR=0.87, 95%CI=0.79-0.97, PH=0.000; GG vs. AA: OR=0.75, 95%CI= 0.65-0.86, PH=0.000; GG vs. GA+AA: OR=0.84, 95%CI=0.79-0.91, PH=0.001; GG+GA vs. AA: OR=0.83, 95%CI=0.74-0.92, PH=0.000). Stratified analysis by cancer type revealed that the CTLA-4+49A/G polymorphism is associated with the decreased risk of cervical cancer, breast cancer, lung cancer, HCC. Further subgroup analysis by ethnicity indicated that there was a statistically decreased cancer risk in Asian population. CONCLUSION: This meta-analysis suggests that CTLA-4+49A/G polymorphism is associated with cancer risk, especially in Asian population.