Zhengjin Yang

• PhD
• Professor at University of Science and Technology of China

Studying ion transport in the interaction confinement regime has important implications for membrane design and advanced electrochemical devices. A key example is the rapid-charging capability of aqueous organic redox flow batteries, enabled by near-frictionless Na⁺/K⁺ transport within triazine framework membranes. However, achieving similar breakt...

Aqueous organic redox flow batteries (AORFBs) represent a potent technology in low‐cost storage and grid‐scale adoption of renewable electricity, whereas bipyridinium derivatives, the most extensively adopted anolyte, undergo diverse side reactions causing severe loss of battery lifetime. Here, we propose a strategy to promote the formation of intr...

Aqueous organic redox flow batteries (AORFBs) represent a potent technology in low‐cost storage and grid‐scale adoption of renewable electricity, while bipyridinium derivatives, the most extensively adopted anolyte, undergo diverse side reactions causing severe loss of battery lifetime. Here we propose a strategy to promote the formation of intramo...

Ultrathin and robust composite anion exchange membranes are developed by infiltrating poly(biphenyl piperidinium) solution into PE porous substrate and overcoming the poor wettability of the PE substrate in a pore‐filling procedure. By strengthening the binding between ionomers and the porous substrate via a physical interlocking strategy, symmetri...

2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives are typical catholytes in aqueous organic redox flow batteries (AORFBs), but reported lifetime of them is limited. We find that the increase of Hirshfeld charge decreases the Gibbs free energy change (ΔG) values of side reactions of TEMPO, a near-linear relationship, and then exacerbates thei...

Aqueous organic redox flow batteries (AORFBs), which exploit the reversible redox reactions of water-soluble organic electrolytes to store electricity, have emerged as a promising electrochemical energy storage technology. Organic electrolytes possess fast electron-transfer rates that are two or three orders of magnitude faster than those of their...

Ion exchange membranes (IEMs) enable the fast and selective ion transport and the partition of electrode reactions, playing an imperative role in the fields of precise ion separation, renewable energy storage and conversion, and clean energy production. Traditional IEMs form ion channels at the nanometer-scale via the assemble of flexible polymeric...

High-temperature proton exchange membrane fuel cells based on phosphoric acid-doped polybenzimidazole (PBI) materials face challenges of low power output and low Pt utilization due to the lack of suitable electrode binders. We have developed a sulfonated microporous polymer material (namely, SPX, i.e., sulfonated polyxanthene) with excellent chemic...

Ion exchange membranes (IEMs) play a critical role in aqueous organic redox flow batteries (AORFBs). Traditional IEMs that feature microphase‐separated microstructures are well‐developed and easily available but suffer from the conductivity/selectivity tradeoff. The emerging charged microporous polymer membranes show the potential to overcome this...

Ion exchange membranes (IEMs) play a critical role in aqueous organic redox flow batteries (AORFBs). Traditional IEMs that feature microphase‐separated microstructures are well developed and easily available but suffer from the conductivity/selectivity tradeoff. The emerging charged microporous polymer membranes show the potential to overcome this...

Ion exchange membranes are semi-permeable thin films allowing for selective transport of either anions or cations and have wide applications in desalination, wastewater treatment and energy conversion and storage. Poly(aryl piperidinium) polymers are promising materials for a new generation of anion exchange membranes with high chemical stability,...

The understanding gleaned from studying ion transport within the interaction confinement regime enables the near-frictionless transport of cations ( e.g., Na ⁺ /K ⁺ ). However, anion transport ( e.g., Cl ⁻ ) is suppressed under confinement because of the different polarization of water molecules around cations and anions, also known as the charge a...

Alkaline zinc‐based flow batteries (AZFBs) have emerged as a promising electrochemical energy storage technology owing to Zn abundance, high safety, and low cost. However, zinc dendrite growth and the formation of dead zinc greatly impede the development of AZFBs. Herein, a dual‐function electrolyte additive strategy is proposed to regulate zinc nu...

The recovery of acid/base from industrial wastewater via membrane technology is energy efficient and has a low carbon footprint, while demanding high‐performing ion exchange membranes. It remains a grand challenge for ion exchange membranes, enabling concomitantly fast H⁺/OH⁻ transport and high ion selectivity. This article presents a negatively ch...

State-of-the-art high-temperature polymer electrolyte membrane fuel cells enabled by the phosphoric acid-doped polybenzimidazole material platform are promising for long-haul transport, but suffer from low output power, low Pt utilization, and...

Anion-exchange membranes (AEMs) that can selectively transport OH-, namely, alkaline membranes, are becoming increasingly crucial in a variety of electrochemical energy devices. Understanding the membrane design approaches can help to break through the constraints of undesired performance and lab-scale production. In this Outlook, the research prog...

The lack of high-performance and substantial supply of anion-exchange membranes is a major obstacle to future deployment of relevant electrochemical energy devices. Here, we select two isomers (m-terphenyl and p-terphenyl) and balance their ratio to prepare anion-exchange membranes with well-connected and uniformly-distributed ultramicropores based...

The enhancement of separation processes and electrochemical technologies such as water electrolysers1,2, fuel cells3,4, redox flow batteries5,6 and ion-capture electrodialysis⁷ 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 barrie...

Lithium extraction via membrane-based technologies from salt-lake brines has become an exciting research direction. However, the lithium extraction efficiency is drastically affected by Mg²⁺ ions, which have similar chemical and physical properties, and separating Li⁺ from Mg²⁺ is currently the biggest obstacle. Here we designed a Li⁺ selective mem...

In the development of aqueous organic redox flow batteries (AORFBs), anthraquinone derivatives (AQs) attract a great deal of attention as the most promising negative electrolytes. Molecular structures of AQs have...

Aqueous organic redox flow batteries (AORFBs), which exploit the reversible electrochemical reactions of water soluble organic electrolytes to store electricity, gain increasing momentum for the grid‐scale integration of renewable electricity. However, the crossover of organic electrolytes across the membrane and the limited capacity significantly...

Aqueous organic redox flow batteries (AORFBs) are promising candidates for the large-scale storage of intermittent renewable energy because of their technological advantages of decoupled power and capacity, convenient scale up, diverse organic molecules, potential low cost, and high safety. In this perspective, we focus on the development of two-el...

Aqueous organic redox flow battery (AORFB) operating in pH-neutral solutions is an attractive electrochemical energy storage device because of its decoupled energy and power, high safety, low corrosivity, and potentially low cost. However, it remains largely unclear how to develop high-performing AORFB membranes that enable fast ion transport while...

Ion exchange membranes (IEMs) that can selectively transport ions are crucial to a variety of applications, such as ion extraction/separation, fuel cells, redox flow batteries, and water electrolysis. IEM performance, in terms of membrane permeability/conductivity and selectivity, relies heavily on the formation of effective ion transport channels...

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...

Biological sodium channels have selectivity filters with extraordinary Na⁺ selectivity. Realizing this function in ion exchange membranes is highly desirable for technologies related to water, energy, and the environment, but it remains a challenge. Here we report a sodium selective isoporous membrane (NaSIM) derived from lyotropic liquid crystals....

Polymer electrolyte membranes are charged polymers in the membrane shape, which can separate the anode reaction from the cathode reaction, allowing the fabrication of compact and highly efficient electrochemical devices. In recent years, great success has been witnessed in the development of advanced polymer electrolyte membranes, driven by the fas...

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 rea...

Energy conversion from waste acid and base can be realized by reverse electrodialysis with the acid-base neutralization (REDn). However, poor energy conversion performances, such as the low voltage and the low power density (<0.5 W/m²), caused by the high resistance and the low voltage of cell pair of “anion-exchange membrane (AEM) + neutral compar...

Membrane-based electrochemical devices can extract electricity from solutions of different salinity, namely osmotic energy. This is, however, limited to salinity differences between seawater and river water, whereas the efficiency is...

Due to decoupled energy and power, the aqueous organic redox flow battery (AORFB) represents a promising energy storage technology that stores energy in redox-active organic compounds dissolved in aqueous electrolytes. The organic compounds are composed of earth-abundant elements and are therefore potentially cost-effective. Their structures are di...

Aqueous organic redox flow batteries (AORFBs) represent a promising energy storage technology that may enable the grid-scale integration of intermittent renewable energy. The water-soluble, redox-active organic species that are utilized to reversibly store electricity are the most critical performance-determining components in AORFBs. To ensure aff...

Much remains unknown for the selective translocation of ions across microporous polymeric membranes and it maintains a daunting challenge to pursue a polymeric membrane that can efficiently separate both anions and cations of comparable size. Here we explore the ion transport across hydrophilic microporous membrane derived from polymers of intrinsi...

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 red...

The Cover Feature shows the design and molecular engineering of ferrocene‐based catholyte from the molecular orbital perspective, affording capable candidates for practical aqueous flow battery applications. Combined electrochemical investigations and DFT calculations reveal how the catholyte structures, electrochemical properties, and battery perf...

Precise manipulation of the polyelectrolyte self-assembly process, to form the desired microstructure with ion-conducting channels, is of fundamental and technological importance to many fields, such as fuel cells, flow batteries and electrodialysis. To fabricate anion exchange membranes (AEMs) with highly conductive and alkaline stable ion-conduct...

The increasing energy demand of human society boosts the exploitation of renewable energy, whereas the intermittence and fluctuation of renewable energy necessitate the deployment of high-performance and cost-effective energy storage technology. Aqueous organic flow battery (AOFB) is a novel system with decoupled capacity and power, which stores en...

A novel strategy regarding visible light-induced RAFT polymerization for preparing polyolefin-based anion exchange membranes (AEMs) under facile conditions is presented. The molecular weight of poly(2-chloroethyl vinyl ether) (PCEVE) backbone can...

Ferrocene (Fc) is one of the very limited organic catholyte options for aqueous organic flow batteries (AOFBs), a potential electrochemical energy storage solution to the intermittency of renewable electricity. Commercially available Fc derivatives are barely soluble in water, while existing methods for making water‐soluble Fc derivatives by append...

The aqueous organic flow battery (AOFB) holds enormous potential as an energy storage device for fluctuating renewable electricity by exploiting the redox reactions of water‐soluble organic molecules. The current development is impeded by lack of organic molecules adequate as catholyte, yet how the catholyte structure impacts the battery lifetime r...

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 prot...

Layer-by-layer (LBL) assembly is one of the most universal membrane coating practices today to reduce the fuel (e.g., methanol) crossover problem in fuel cells. However, scientific uses of traditional LBL assemblies are obstructed by the fluid-demanding and laborious nature of the method. We report an approach to the fabrication of layered anion ex...

Ion exchange membrane plays a crucial role in transforming and upgrading traditional chemical manufacturing procedures and boosting a multitude of new applications. Due to the strict regulations on wastewater discharge and increasing demands of renewable energy, anion exchange membrane (“A” membrane), bipolar membrane (“B” membrane) and cation exch...

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...

The practical application of Li anodes is significantly hindered by the growth of Li dendrites that may cause severe safety issues. To inhibit the Li dendrites, coating an artificial layer on the Li metal anode has been proved as a facile and effective approach. In their review on page 4193 ff., Shijun Zhang, Zhengjin Yang, Liangliang Qu, Weixia Zh...

Membranes which allow 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 (PEMFCs) and redox flow batteries (RFBs). Herein we report a new approach to designing solution‐processable ion‐selective polymer membrane...

Viologen derivatives have been developed as negative electrolyte for neutral aqueous organic redox flow batteries (AOFBs), but the structure–performance relationship remains unclear. Here, it was investigated how the structure of viologens impacts their electrochemical behavior and thereby the battery performance, by taking hydroxylated viologens a...

Membranes: Sulfonated polyxanthene membranes with both intrinsic microporosity and conductive functionality were synthesized. They exhibit high ion conductivity and high selectivity towards redox-active anions. They significantly enhance the performance of redox flow batteries and hydrogen fuel cells, demonstrating the design is broadly applicable....

Lithium (Li) metal is considered as the most promising anode material for rechargeable high‐energy batteries. Nevertheless, the practical implement of Li anodes is significantly hindered by the growth of Li dendrites, which can cause severe safety issues. To inhibit the formation of Li dendrites, coating an artificial layer on the Li metal anode ha...

g‐C3N4 membranes were modulated by intercalating molecules with SO3H and benzene moieties between layers. The intercalation molecules break up the tightly stacking structure of g‐C3N4 laminates successfully and accordingly the modified g‐C3N4 membranes give rise to two orders magnitude higher water permeances without sacrificing the separation effi...

Saure Abstandhalter: Inspiriert von der Architektur von Graphenoxid-Laminaten wurden g-C3N4-Membranen moduliert, indem Moleküle mit SO3H- und Benzoleinheiten zwischen den Schichten interkaliert wurden. Gegenüber der reinen g-C3N4-Membran ergeben die modifizierten g-C3N4-Membranen eine um zwei Größenordnungen höhere Wasserdurchlässigkeit, ohne dabei...

Polymer electrolyte membrane fuel cells can generate high power densities with low local emissions of pollutants. Opti-mal ionomer-Pt/C catalyst interactions in the electrodes enables the efficient generation and transport of ions and elec-trons required for high fuel cell performances. Critical durability issues involve agglomeration of the Pt/C n...

The performance and safety of lithium (Li) metal batteries can be compromised owing to the formation of Li dendrites. Here, the use of a polymer of intrinsic microporosity (PIM) is reported as a feasible and robust interfacial layer that inhibits dendrite growth. The PIM demonstrates excellent film‐forming ability, electrochemical stability, strong...

Artificial counterparts of conical‐shaped transmembrane protein channels are of interest in biomedical sciences for biomolecule detection and selective ion permeation based on ionic size and/or charge differences. However, industrial‐scale applications such as seawater desalination, separation of mono‐ from divalent cations, and treatment of highly...

To ameliorate the trade-off effect between ionic conductivity and water swelling of anion exchange membranes (AEMs), a crosslinked, hyperbranched membrane (C-HBM) combining the advantages of densely functionalization architecture and crosslinking structure was fabricated by the quaternization of the hyperbranched poly(4-vinylbenzyl chloride) (HB-PV...

Conical‐shaped transmembrane protein channels are essential for the transport of ions across lipid bilayers in biological tissues and organisms. Their artificial counterparts are of high applicative interest in biomedical sciences for biomolecule detection and selective ion permeation based on ionic‐size and/or charge differences. However, industri...

Salinity gradient power (SGP) has attracted extensive research interests as a renewable energy source. Compared with energy generated from solar and wind, the direct adoption of SGP is currently impractical. Splitting water in salinity-gradient-power driven reverse electrodialysis, appears to be an effective way to utilize such energy, producing hi...

Aqueous organic flow battery (AOFB) is a promising energy storage solution featuring low cost, easy scale-up, and improved safety. Extensive research effort has been devoted to exploring redox-active organic compounds, while another critical component, the ion conducting membrane is overlooked. Here we demonstrate the syntheses of an anion conducti...

Anion exchange membranes (AEMs) are crucial components for advanced energy and environment processes including alkaline fuel cells, redox flow batteries, and industrial effluent treatment; while low anionic conductivity and poor stability remain the major challenges for the widespread implementation of AEMs. Through molecular engineering, comb-shap...

The massive-scale integration of renewable electricity into the power grid is impeded by its intrinsic intermittency. The aqueous organic redox flow battery (AORFB) rises as a potential storage solution; however, the choice of positive electrolytes is limited, and the aqueous-soluble organic positive redox-active species reported to date have short...

Anion exchange membranes (AEMs) separate the redox active electrolytes and transfer the charge carriers in redox flow batteries. During the long-term operation of a redox flow battery, the formation and propagation of cracks in AEMs are detrimental, resulting in capacity loss and self-discharge, while replacing the cracked membranes would increase...

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 doomed many organic compounds because of their sluggish electrochemical kinetics, which would compromise the power capability of an...

Anion exchange membrane is a key component that determines the performance of diffusion dialysis process for acid recovery. This study reports a novel anion exchange membrane composed of poly vinyl alcohol (PVA), quaternized 1-hydroxy-N, N-dimethyl-N-(pyridine-2-ylmethyl) methanaminium (QUDAP) and tetraethyl orthosilicate (TEOS) prepared by classic...

As a critical component of alkaline fuel cells, anion exchange membranes determine the energy efficiency, output power density and the long term stability. Recently, the anion exchange membranes with gemini-cation side chains exhibit superior ion conductivity due to their good nanophase separation. However, the costly and complicated synthesis limi...

Developing anion exchange membranes that have high anion selectivity and can avoid membrane swelling is a critical, but challenging target for electrodialysis, which has witnessed great success in a wide range of applications including saline wastewaters treatment, and resource recovery. We found in this work that by tuning the hydrophobicity of al...

To meet the ever-increasing demand of energy conversion/storage devices on anion exchange membrane (AEM) conductivity, it is urgent to explore alternate polymers in terms of the backbone architecture. In contrast to linear polymers, hyper-branched polymers exhibit unexpected properties because of the unique backbone architecture. Unfortunately, rep...

Conventionally, CO2 is recovered using heat stripping method in the carbon capture and sequestration process (CCS), which requires a large amount of energy, and an amine treatment unit to remove heat stable salt (HSS). The energy consumed in CO2 recovery accounts for a large fraction of the total energy required for the CCS process. In this work, a...

Anion exchange membrane fuel cells (AEMFCs) can efficiently convert chemical energy into electricity at high pH. However, as the critical component, the existing anion exchange membranes (AEMs), cannot have both high stability and high conductivity, which is intrinsic to the conventional linear AEMs. To address this, here we report hyperbranched AE...

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(phen...

Covalent crosslinking is an effective method to stabilize anion exchange membranes (AEMs) against water swelling and high alkaline environment, yet complicated process is required. We report herein a straightforward approach to prepare highly crosslinked, transparent and flexible AEM by simply immersing a halo-alkylated polymer (e.g., brominated po...

Synthetic polyelectrolytes, capable of fast transporting protons, represent a challenging target for membrane engineering in so many fields, for example, fuel cells, redox flow batteries, etc. Inspired by the fast advance in molecular machines, here we report a rotaxane based polymer entity assembled via host-guest interaction and prove that by exp...

Monovalent cations permselective membranes (MCPMs) which can selectively transport monovalent and reject the multivalent cations are key materials for waste water treatment, mining of valuable seawater metal ions, acid recovery in hydrometallurgy etc. High flux and good selectivity are desired characteristics for practical applications of MCPMs. In...

To access highly ion-conductive membrane materials which are urgently desired by the technologies like fuel cells, flow batteries, electro-dialysis etc., a novel polymer architecture featured by the densely grafting of three ionic strings onto each benzene ring was developed. Compared with the previous densely functionalized AEMs prepared by closel...

In article number 1702056 Roy G. Gordon, Michael J. Aziz and co-workers, introduce an aqueous flow battery based on low-cost, nonflammable, noncorrosive, and earth-abundant elements. During charging, electrons are stored in a concentrated aqueous solution of 2,5-dihydroxy-1,4-benzoquinone, which rapidly receives electrons from inexpensive carbon el...

Highly conductive anion exchange membranes (AEMs) are urgently desired for various electro-chemical technologies like fuel cells, flow batteries and electro-dialysis. Available strategies for enhancing hydroxide conductivity of a AEM commonly focus on increasing the concentration of the cationic sites, but, in turn, causes undesirable, excessive di...

Poly(2,6-dimethyl-1,4-phenylene oxide) was tethered with a 1,5-disubstituted tetrazole through a quaternary ammonium linkage. The formation of a tetrazole-ion network in the resulting polymers was found to promote the hydroxide ion transport through the Grotthus-type mechanism.

An aqueous flow battery based on low-cost, nonflammable, noncorrosive, and earth-abundant elements is introduced. During charging, electrons are stored in a concentrated water solution of 2,5-dihydroxy-1,4-benzoquinone, which rapidly receives electrons with inexpensive carbon electrodes without the assistance of any metal electrocatalyst. Electrons...

Cross-linking can effectively solve the conductivity-swelling dilemma in anion exchange membranes (AEMs) but will generate solid wastes. To address this, we developed an AEM cross-linked via disulfide bonds, bearing quaternary ammonium groups, which can be easily recycled. The membrane (RC-QPPO) with IEC of 1.78 mmol g⁻¹, when cross-linked, showed...

Anion exchange membrane is a key component that determines the performance of diffusion dialysis process for acid recovery. This study reports a novel anion exchange membrane composed of poly vinyl alcohol (PVA), quaternized 1-hydroxy-N, N-dimethyl-N-(pyridine-2-ylmethyl) methanaminium (QUDAP) and tetraethyl orthosilicate (TEOS) prepared by classic...

Ion exchange membranes (IEMs) have great potential in diverse applications and play prominent roles in addressing energy and environment related issues. Over the past decade, the development of IEMs has attracted much research attention in terms of materials, preparation and applications, due to their academic and industrial values. In this review,...

Heterogeneous cation exchange membranes for potential electrodialysis (ED) seawater desalination were fabricated using poly (vinyl chloride) (PVC) as binder and functional polymer powders (sPSt-co-DVB) as polyelectrolyte by a cost effective hot-press process. Physical and electrochemical properties of the prepared membranes were investigated to eva...