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The enhancement of separation processes and electrochemical technologies such as water electrolysers, fuel cells, redox flow batteries and ion-capture electrodialysis depends on the development of low-resistance and high-selectivity ion-transport membranes. The transport of ions through these membranes depends on the overall energy barriers imposed by the collective interplay of pore architecture and pore–analyte interaction. However, it remains challenging to design efficient, scaleable and low-cost selective ion-transport membranes that provide ion channels for low-energy-barrier transport. Here we pursue a strategy that allows the diffusion limit of ions in water to be approached for large-area, free-standing, synthetic membranes using covalently bonded polymer frameworks with rigidity-confined ion channels. The near-frictionless ion flow is synergistically fulfilled by robust micropore confinement and multi-interaction between ion and membrane, which afford, for instance, a Na+ diffusion coefficient of 1.18 × 10−9 m2 s–1, close to the value in pure water at infinite dilution, and an area-specific membrane resistance as low as 0.17 Ω cm2. We demonstrate highly efficient membranes in rapidly charging aqueous organic redox flow batteries that deliver both high energy efficiency and high-capacity utilization at extremely high current densities (up to 500 mA cm–2), and also that avoid crossover-induced capacity decay. This membrane design concept may be broadly applicable to membranes for a wide range of electrochemical devices and for precise molecular separation.

Bipyridinium derivatives represent the most extensively explored anolyte materials for pH-neutral aqueous organic redox flow batteries, and most derivatives feature two separate electron-transfer steps that cause a sharp decrease in cell voltage during discharge. Here, we propose a strategy to fulfill the concurrent two-electron electrochemical reaction by designing extended bipyridinium derivatives (exBPs) with a reduced energy difference between the lowest unoccupied molecular orbital of exBPs and the β-highest occupied molecular orbital of the singly reduced form. To demonstrate, a series of exBPs are synthesized and exhibit a single peak at redox potentials of -0.75 to -0.91 V (vs standard hydrogen electrode (SHE)), as opposed to the two peaks of most bipyridinium derivatives. Cyclic voltammetry along with diffusion-ordered spectroscopy and rotating disk electrode experiments confirm that this peak corresponds to a concurrent two-electron transfer. When examined in full-flowing cells, all exBPs demonstrate one charge/discharge plateau and two-electron storage. Continuous galvanostatic cell cycling reveals the side reactions leading to capacity fading, and we disclose the underlying mechanism by identifying the degradation products. By prohibiting the dimerization/β-elimination side reactions, we acquire a 0.5 M (1 M e

An ultramicroporous membrane provides highly selective ion transport, enabling power generation from solutions with/without salinity difference, or potentially from wastewater. This extends the concept of extracting Gibbs energy from solution mixing.

Aqueous flow batteries (AFBs) are among the most promising electrochemical energy storage solutions for the massive-scale adoption of renewable electricity because of decoupled energy and power, design flexibility, improved safety and low cost. The development of high-voltage AFB is, however, limited by the lack of stable anolytes that have low redox potential. Here we report Eu-based anolytes for high-voltage pH-neutral AFB applications. Eu3+ has a reduction potential of −0.39 V vs. SHE, which can be dramatically lowered when forming stable complex with inexpensive organic chelates. A typical complex, EuDTPA, features a low redox potential of −1.09 V vs. SHE, fast redox kinetics, and a high water solubility of 1.5 M. When paired with ferrocyanide, the battery had an open-circuit voltage of 1.56 V and demonstrated stable cell cycling performance, including a capacity retention rate of 99.997% per cycle over 500 cycles at 40 mA cm−2, a current efficiency of >99.9%, and an energy efficiency of >83.3%. A high concentration anolyte at 1.5 M exhibited a volumetric capacity of 40.2 Ah L−1, which is one of the highest known for pH-neutral AFBs, promising a potent solution for the grid-scale storage of renewable electricity.

Many separation, purification processes and electrochemical technologies such as water electrolysers1,2, fuel cells3,4, redox flow battery5,6 and ion-capture electrodialysis7 hinge on the development of low-resistance and high-selectivity ion-transport membranes (SIMs). The transport of ions through SIMs depends on the overall energy barrier which are imposed by the collective interplay of pore architecture and pore-analytes interaction8,9. However, it remains challenging to design efficient, scalable and low-cost SIMs with low-energy-barrier ion channels. Here we pursue a strategy to approach the diffusion limit of ions in water for large-area free-standing synthetic membranes using covalently bonded polymer frameworks with rigidity-confined ion channels. The near-frictionless ion flow is synergistically fulfilled by robust micropore confinement and multi-interaction between ion and membrane, which afford, for instance, a Na+ diffusion coefficient of is 1.18×10-9 square meter per second, close to the value in pure water at infinite dilution and an area-specific membrane resistance as low as 0.17 Ohm square centimeter. We demonstrate the great efficacy of membranes in fast-charging aqueous organic redox flow batteries that deliver both high energy efficiency and high capacity utilization at extremely high current densities (up to 500 milliampere per square centimeter), while avoiding crossover-induced capacity decay. This membrane design concept may be broadly applicable to membranes for a wide range of electrochemical devices and for precise molecular separation.

Long-term arsenic (As) exposure can cause liver injury, hepatic cirrhosis, and cancer. Meanwhile, Dictyophora polysaccharides (DIP) have excellent antioxidation, anti-inflammation, and immune protection effects. There are currently few reports on the protection effects of DIP on As-induced hepatotoxicity and its pharmacological value. Therefore, this study was aimed at elucidating the protection of DIP on As-induced hepatotoxicity and exploring its preventive role in antifibrosis. In our study, the SD rat As poisoning model was established by the feeding method to explore the influence of As exposure on liver fibrosis. Then, DIP treatment was applied to the rats with As-induced liver fibrosis, and the changes of serum biochemical indexes and liver tissue pathology were observed. And the expression of fibrosis-related proteins TGF-β1, CTGF, and α-SMA levels was then determined to explore the DIP intervention function. The results demonstrated that through reduced pathological changes of hepatic and increased serum AST, ALT, TP, ALB, and A/G levels, DIP ameliorated liver fibrosis induced by As as reflected. And the administration of DIP decreased the concentration of HA, LN, PCIII, CIV, TBIL, and DBIL. In addition, the synthesis of TGF-β1 inhibited by DIP might regulate the expression of CTGF and decrease the proliferation of fibrinogen and fibroblasts, which reduced the synthesis of fibroblasts to transform into myofibroblasts. And a decrease of myofibroblasts downregulated the expression of α-SMA, which affected the synthesis and precipitation of ECM and alleviated the liver fibrosis caused by exposure to As. In conclusion, based on the pathological changes of liver tissue, serum biochemical indexes, and related protein expression, DIP can improve the As-induced liver fibrosis in rats and has strong medicinal value.

NaAsO2-induced liver damage leads to autophagy, which plays an important role in cell quality control. Mitophagy plays an important role in hepatocyte damage, and PINK1 and Parkin constitute an important pathway in mitophagy. PINK1 selectively degrades abnormal mitochondria, and Parkin can recognize damaged mitochondria. However, the mechanism underlying the involvement of PINK1/Parkin in NaAsO2-induced mitophagy is unclear. Transfection plasmids containing dsRNA were used to interfere with the expression of Parkin in the following groups: the empty plasmid group was established by add the empty plasmid only, the PINK1-knockdown (KD) group was established by adding 5 μg of PINK1 dsRNA and then by adding 10 mM NaAsO2, and the Parkin-KD group was established by adding 5 μg of Parkin dsRNA and then by adding 10 mM NaAsO2. The expression of PINK1 and Parkin in autophagy was detected by western blotting and immunofluorescence staining. The ultrastructures of autophagosomes and mitochondria were observed by transmission electron microscopy. The successful KD of PINK1 and Parkin aggravated the NaAsO2-induced damage to mitophagy. The degeneration of mitochondrial vacuoles and the appearance of autophagosomes were detected in the NaAsO2, NaAsO2 + PINK1-KD and NaAsO2 + Parkin-KD groups. NaAsO2 can induce mitophagy in rat hepatocytes, and the silencing of PINK1 and Parkin can aggravate mitochondrial damage during this process. This study explored the mechanism of NaAsO2-induced mitophagy in BRL-3A cells after PINK1 and Parkin gene silencing.

Hepatocellular carcinoma (HCC) is one of the most fatal cancers worldwide. In this article, we show that expression of abnormal spindle‐like microcephaly‐associated protein (ASPM) is up‐regulated in liver cancer samples, and this up‐regulation is significantly associated with tumor aggressiveness and reduced survival times of patients. Down‐regulation of ASPM expression inhibits the proliferation, invasion, migration and epithelial‐to‐mesenchymal transition of HCC cells in vitro and inhibits tumor formation in nude mice. ASPM interacts with disheveled‐2 (Dvl2) and antagonizes autophagy‐mediated Dvl2 degradation by weakening the functional interaction between Dvl2 and the lipidated form of microtubule‐associated proteins 1A/1B light chain 3A (LC3II), thereby increasing Dvl2 protein abundance and leading to Wnt/β‐catenin signaling activation in HCC cells. Thus, our results define ASPM as a novel oncoprotein in HCC and indicate that disruption of the Wnt–ASPM–Dvl2–β‐catenin signaling axis might have potential clinical value., The abnormal spindle‐like microcephaly‐associated protein (ASPM) promotes hepatocellular carcinoma progression by activating Wnt/β‐catenin signaling. ASPM interacts with disheveled‐2 (Dvl2) and antagonizes autophagy‐mediated Dvl2 degradation by weakening the functional interaction between Dvl2 and the lipidated form of microtubule‐associated proteins 1A/1B light chain 3A (LC3II), thereby increasing Dvl2 protein abundance and leading to Wnt/β‐catenin signaling activation in HCC cells.

Aqueous organic flow batteries (AOFBs) are promising energy storage solutions to counteract the intermittent and fluctuating nature of renewable energy. However, we have limited options of electrolyte chemistry and we discarded many organic compounds because of their sluggish electrochemical kinetics, which would compromise the power capability of an AOFB. Here, exemplified by 2,5-dihydroxy-3,6-dimethyl-1,4-benzoquinone (DMBQ), we present two approaches including engineering the molecular structure and utilizing an inexpensive catalyst to enhance the electrochemical kinetics of benzoquinones with the ultimate purpose of diminishing the electron transfer barrier thereby increasing the power capability of the AOFB. We show that, by exploiting these strategies, the electron transfer resistance could be reduced by 48.1%, or 55.8%, respectively, thereby leading to a 49.4% or 60.7% increase in the peak power density of a flowing cell. We believe our strategy could be extended to the full family of quinones and ...

Ion and water transfer in subnanometer-sized confined channels of hydrophilic microporous polymer membranes show enormous potential in tackling the ubiquitous trade-off between permeability and selectivity for energy and environment-related membrane technologies. To this end, a variety of hydrophilic polymers of intrinsic microporosity (HPIMs) have been developed. Herein, the synthetic strategies toward HPIMs are summarized, including post-synthetic modification of polymers to introduce polar groups (e. g., amines, hydroxy groups, carboxylic acids, tetrazoles) or charged moieties (e. g., quaternary ammonium salts, sulfonic acids), and the polymerization of hydrophilic monomers. The advantages of HPIM membranes over others when employed in energy conversion and storage, acid gas capture and separation, ionic diodes, and ultrafiltration, are highlighted.

Membranes with fast and selective transport of protons and cations are required for a wide range of electrochemical energy conversion and storage devices, such as proton‐exchange membrane (PEM) fuel cells and redox flow batteries. Here we report a new approach to designing solution‐processable ion‐selective polymer membranes with both intrinsic microporosity and ion‐conductive functionality. This was achieved by synthesizing polymers with rigid and contorted backbones, which incorporate hydrophobic fluorinated and hydrophilic sulfonic acid functional groups, to produce membranes with negatively‐charged subnanometer‐sized confined ionic channels. The facilitated transport of protons and cations through these membranes, as well as high selectivity towards nanometer‐sized redox‐active molecules, enable efficient and stable operation of an aqueous alkaline quinone redox flow battery and a hydrogen PEM fuel cell. This membrane design strategy paves the way for producing a new‐generation of ion‐exchange membranes for electrochemical energy conversion and storage applications.

Ion exchange membranes (IEMs) play a significant role in fields of energy and environment, for instance fuel cells, diffusion dialysis, electrodialysis, etc. The limited choice of commercially available IEMs has produced a strong demand of fabricating IEMs with improved properties via facile synthetic strategies over the past two decades. Poly(phenylene oxide) (PPO) is considered as a promising polymeric material for constructing practical IEMs, due to its advantages of good physicochemical properties, low manufacturing cost and easy post functionalization. In this review, we present the accumulated efforts in synthetic strategies towards diverse types of PPO-based IEMs. Relation between polymer structures and the resulted features is discussed in detail. Besides, applying IEMs from PPO and its derivatives in fuel cell, diffusion dialysis and electrodialysis is summarized and commented.

The grid-scale integration of solar or wind energy that fluctuates over time will compromise the stability of the power grid. All-vanadium redox flow battery (VRFB) is among the most feasible electrochemical energy storage solutions, while the grand challenge is to develop membranes that separate vanadium electrolytes effectively and transport protons rapidly. Here we present highly conductive and vanadium sieving microporous membranes from shape persistent Trӧger's Base polymer. The N-rich and microporous polymer skeleton facilitate H+ transport. In contrast, hydrated vanadium ions are blocked due to size exclusion and coulombic repulsion. This increases the H/V selectivity of the membrane to >6300, lowers the membrane resistance to 0.57 Ω cm2, and raises the battery power density to 710.9 mW cm−2. A round-trip energy efficiency of 80% and a coulombic efficiency of >99% are maintained during long periods of charge/discharge. We believe the results will stimulate new directions for advanced VRFB membranes.

In this paper, by using qualitative analysis and the first-order Melnikov function method, we consider two kinds of polynomial systems, and study the Hopf bifurcation problem, obtaining the maximum number of limit cycles.