Olefin-Linked Covalent Organic Frameworks with Electronegative Channels as Cationic Highways for Sustainable Lithium Metal Battery Anodes.

Despite the enormous interest in Li metal as an ideal anode material, the uncontrollable Li dendrite growth and unstable solid electrolyte interphase have plagued its practical application. These limitations can be attributed to the sluggish and uneven Li+ migration towards Li metal surface. Here, we report olefin-linked covalent organic frameworks (COFs) with electronegative channels for facilitating selective Li+ transport. The triazine rings and fluorinated groups of the COFs are introduced as electron-rich sites capable of enhancing salt dissociation and guiding uniform Li+ flux within the channels, resulting in a high Li+ transference number (0.85) and high ionic conductivity (1.78 mS cm-1 ). The COFs are mixed with a polymeric binder to form mixed matrix membranes. These membranes enable reliable Li plating/stripping cyclability over 700 h in Li/Li symmetric cells and stable capacity retention in Li/LiFePO4 cells, demonstrating its potential as a viable cationic highway for accelerating Li+ conduction.

Distributed Li-Ion Flux Enabled by Sulfonated Covalent Organic Frameworks for High-Performance Lithium Metal Anodes.

Metallic Li is considered the most promising anode material for high-energy-density batteries owing to its high theoretical capacity and low electrochemical potential. However, inhomogeneous lithium deposition and uncontrollable growth of lithium dendrites result in low lithium utilization, rapid capacity fading, and poor cycling performance. Herein, two sulfonated covalent organic frameworks (COFs) with different sulfonated group contents are synthesized as the multifunctional interlayers in lithium metal batteries. The sulfonic acid groups in the pore channels can serve as Li-anchoring sites that effectively coordinate Li ions. These periodically arranged subunits significantly guide uniform Li-ion flux distribution, guarantee smooth Li deposition, and reduce lithium dendrite formation. Consequently, these characteristics afford an excellent quasi-solid-state electrolyte with a high ionic conductivity of 1.9 × 10-3  S  cm-1 at room temperature and a superior Li++ transference number of 0.91. A Li/LiFePO4 battery with the COF-based electrolyte exhibited dendrite-free Li deposition during the charge process, accompanied by no capacity decay after 100 cycles at 0.1 C.

Covalent Organic Frameworks with Tailored Functionalities for Modulating Surface Potentials in Triboelectric Nanogenerators.

Designing materials with high triboelectric is an efficient way of improving output performance of triboelectric nanogenerators (TENGs). Herein, we synthesized a series of covalent organic frameworks (COFs) with similar skeletons but various functional groups ranging between electron-donating and electron-withdrawing. These COFs form an ideal platform for clarifying the contribution of each group to TENG performance because the pore wall is perturbed in a predesigned manner. Kelvin probe force microscopy and computational data suggest that surface potentials and electron affinities of COFs can be improved by introducing electron-donating or withdrawing groups, with the highest values observed for fluorinated COF. The TENG with fluorinated COF delivered an output voltage and current of 420 V and 64 µA, respectively, which are comparable to other reported materials. This strategy can be used to efficiently screen suitable frameworks as TENG materials with excellent output performance.

Body weight, CYP2C19, and P2Y12 receptor polymorphisms relate to clopidogrel resistance in a cohort of Chinese ischemic stroke patients with aspirin intolerance.

PURPOSE: Dual antiplatelet therapy (DAT) with clopidogrel and aspirin is not suitable for clopidogrel resistance (CR) patients with aspirin intolerance. To investigate the prevalence of CR in patients with aspirin intolerance after ischemic stroke (IS) and to assess the relationship between CR and CYP2C19, P2Y12 receptor genotypes in patients with aspirin intolerance after IS. METHODS: We enrolled 126 IS patients with aspirin intolerance from Han Chinese in Shangqiu from January 2016 to November 2018. All IS patients with aspirin intolerance were treated with clopidogrel for 7 days. Adenosine diphosphate-induced platelet inhibition rate was measured by thrombelastography (TEG) mapping assay. The SNPs CYP2C19*2, CYP2C19*3, and P2Y12 receptor (52 G >T) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Binary logistic regression analyses were performed using SPSS version 20.0. RESULTS: The prevalence of CR in patients with aspirin intolerance after IS was approximately 31.0%. Multivariate regression analysis showed that body weight (OR 1.091 (95% CI 1.031-1.155), p = 0.003), CYP2C19 phenotype intermediate metabolizer (IM) (OR 3.820 (95% CI 1.021-14.288), p = 0.046), and CYP2C19 phenotype poor metabolizer (PM) (OR 14.481 (95% CI 2.791-75.129), p = 0.001) significantly increased the risk of CR and P2Y12 receptors (52 G >T) (OR 3.498 [95% CI 1.251-9.784], p = 0.017) increased the risk of CR. CONCLUSIONS: The patients with high body weight, the CYP2C19 phenotypes, and P2Y12 receptor (52 G >T) variant alleles are at risk of CR during clopidogrel treatment in Chinese IS patients with aspirin intolerance. The higher body weight and relevant polymorphisms may help to predict CR in Chinese IS patients with aspirin intolerance.