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The metabolic enzyme methionine adenosyltransferase 2A (MAT2A) was recently implicated as a synthetic lethal target in cancers with deletion of the methylthioadenosine phosphorylase (MTAP) gene, which is adjacent to the CDKN2A tumor suppressor and codeleted with CDKN2A in approximately 15% of all cancers. Previous attempts to target MAT2A with small-molecule inhibitors identified cellular adaptations that blunted their efficacy. Here, we report the discovery of highly potent, selective, orally bioavailable MAT2A inhibitors that overcome these challenges. Fragment screening followed by iterative structure-guided design enabled >10 000-fold improvement in potency of a family of allosteric MAT2A inhibitors that are substrate noncompetitive and inhibit release of the product, S-adenosyl methionine (SAM), from the enzyme's active site. We demonstrate that potent MAT2A inhibitors substantially reduce SAM levels in cancer cells and selectively block proliferation of MTAP-null cells both in tissue culture and xenograft tumors. These data supported progressing AG-270 into current clinical studies (ClinicalTrials.gov NCT03435250).

B-doped pyrolytic carbon from poly(vinylidene fluoride) (PVDF) was used to enhance the performance of a LiVPO4F/C cathode, which is much cheaper than carbon nanotubes and graphene. The carbon layer in LVPF/C-B3 becomes more and more regular compared with the undoped sample. The electronic conductivity, diffusion coefficient, and rate and cycle performance of the B-doped cathode are greatly improved. The capacities of LVPF/C-B3 at 0.2C, 5C, and 15C are 148.1, 132.9, and 125.6 mAh·g-1, which may be the best reported magnitude. The crystallite structure of LiVPO4F/C is well maintained after 300 charge and discharge cycles. The carbonization process of PVDF is greatly accelerated. These improvements are attributed to the changes in chemical and electronic structures. The generation of BC2O and BCO2 results in many defective active sites, and BC3 promotes the growth of a six-membered carbon ring. According to the first-principles approach based on density functional theory, the state density around the Fermi level of the B-doped pyrolytic carbon is increased. The electronic structure of pyrolytic carbon is transformed from a P-type semiconductor to a metal-like structure through the generation of pyridinic-like and graphitic-like B. Therefore, the electronic conductivity of LiVPO4F/C is increased.

Electrochemical CO2 reduction is a promising technology for solving the CO2 emission problems and producing value-added products. Here, we report a hierarchically porous Cu1Au single-atom alloy (SAA) as an efficient electrocatalyst for CO2 reduction. Benefiting from the hierarchically porous architectures with abundant vacancies as well as three-dimensional accessible active sites, the as-prepared nanoporous Cu1Au SAA catalyst shows remarkable CO2 reduction performance with nearly 100% CO Faraday efficiency in a wide potential range (−0.4 to −0.9 V vs . reversible hydrogen electrode. The in-situ X-ray absorption spectroscopy studies and density functional theory calculations reveal that the Cu-Au interface sites serve as the intrinsic active centers, which can facilitate the activated adsorption of CO2 and stabilize the *COOH intermediate.

Ni-based layered transition-metal oxides are advanced cathode materials used in rechargeable Na-ion batteries due to their high specific capacity; however, their applications are blocked by irrever...

The electrochemical reduction of CO2 to an ethanol product is regarded as a highly promising route for CO2 utilization. However, the poor selectivity is still a critical challenge for increasing the yield of the specific ethanol. As a CO2 reduction catalyst, the hierarchically nanoporous copper integrated with vanadium oxide can achieve a 30.1% faradaic efficiency for CO2-to-ethanol production and an ethanol partial current density of −16 mA cm−2 at −0.62 V vs. RHE, corresponding to a 4-fold increase in activity compared to bare nanoporous Cu. It even delivers an ethanol partial current density that exceeds −39 mA cm−2 at −0.8 V vs. RHE in a flow-cell reactor. The hierarchically nanoporous Cu skeleton not only facilitates both electron and electrolyte transport but also provides a large specific surface area for high active site density. Density functional theory reveals that the vanadium oxide decorated Cu surface can facilitate water dissociation and optimize the hydrogen adsorption energy on Cu, lowering the energy barrier for the protonation of carbon dioxide and C–C coupling. Meanwhile, it can increase hydrogen proton coverage on the catalyst surface and inhibit dehydration, which are beneficial for breaking the CC bond of the *HCCOH intermediate, thus enhancing the faradaic efficiency of ethanol significantly. The highly efficient conversion of CO2 to ethanol demonstrates that the hybrid electrocatalyst is considered as a promising candidate for practical electrocatalytic CO2RR applications.

Selenium (Se) is a promising cathode material for next-generation alkali metal–ion batteries due to its high volumetric capacity and good conductivity. Using a first-principles approach, the presen...

The development of alkali metal-ion batteries requires anode materials with high capacity and fast kinetics. The present study theoretically investigates the double-layer honeycomb (DLHC) AlP as a ...

Towards practical lithium–sulfur batteries, the rational design of a sulfur host that enables highly efficient sulfur electrochemistry and high areal sulfur loading is essential but still a challenge. Here, a class of 3D nanocomposite architecture characterised by a necklace-like structure that contains intertwined carbon-nanotubes (CNTs) and defective Prussian blue (PB) nanocrystals is developed as the sulfur host. Benefiting from the fact that a 3D CNT conductive skeleton can provide efficient ion/electron channels and the abundant Lewis acidic sites in PB can effectively entrap lithium polysulfide (LiPS) species, the S@PB/CNT composite cathode exhibits high reversibility, stable cycling performance, and fast kinetics. More importantly, the LiPS adsorption capacity of PB materials and the kinetics of LiPS conversion on PB is highly dependent on the amount of [Fe(CN)6] vacancies based on both theoretical and experimental studies, which may further shed light on the interfacial phenomena between the PB sulfur host and soluble LiPS in the electrolyte.

Ta-doped TiO2/C nanofibers are synthesized by an electrospinning method. First-principles calculations reveal that the Ta dopant can lower the Li/K diffusion barrier, which is beneficial for improving the rate capability. According to the electronic structure analysis, the dopant can obviously shift the conduction band of TiO2 downward, resulting in significantly improved electronic conductivity. Ta doping causes phase transformation from anatase to rutile, and increases the specific surface area. The well-designed rutile Ta-doped TiO2/C nanofibers show outstanding electrochemical properties in both Li-metal half cells and K-metal half cells, which are much better than those of pristine anatase TiO2/C nanofibers. At 2 A g−1, 5% rutile Ta-doped TiO2/C nanofibers could deliver high reversible specific capacities of 399 mA h g−1 in Li-ion batteries after 1000 cycles whereas deliver 148 mA h g−1 in K-ion batteries after 800 cycles. When assembled, the full cells with 5% rutile Ta-doped TiO2/C nanofibers as the anode and commercial LiFePO4/perylene-3,4,9,10-tetracarboxylic dianhydride as the cathode show excellent cycling performance and can light up more than 18 LEDs. These results demonstrate that Ta-doped TiO2/C nanofibers are a promising anode material for Li/K ion batteries.

The influence of cell number on spectral variability among two different cell types and two states was quantitatively analyzed and evaluated by calculating the similarity distance of the single-cell spectral data obtained from synchrotron infrared microspectroscopy. We found that at least 15 cells are required to achieve robust results with 95% confidence.

In this study, carboxyl potassium salt polysulfone PSF-COOK60% was selected as an additive and carboxylated polysulfone PSF-COOH60% was identified as a membrane matrix material to prepare mixed matrix membranes via a traditional phase separation method. The viscosity of the casting solutions, as well as the electronegativity, hydrophilicity, and morphologies of the mixed matrix membranes, greatly changed with the addition of PSF-COOK60%. This was because -COOK was more easily ionized than -COOH into -COO−, which affected the charges, conformations, and hydrophilicity of the polymer chains. In particular, the membrane with a PSF-COOK60%:PSF-COOH60% ratio of 3:7 (M3) exhibited a minimum aperture of 1.825 nm and a maximum electronegativity of −29.9 mV. M3 offered outstanding separation efficiency of dye/salt mixtures as seen in the rejection rates of Congo red (as high as 95.5%) and organic salts (as low as 5.6%), as well as the pure water flux of 153.8 L/m2·h·bar. Furthermore, M3 had excellent anti-dye-fouling performance and showed wide application conditions. Therefore, M3 is an ideal candidate for separation membranes for the fractionation of dye/salt mixtures. The PSF-COOK and other polymer carboxylates can be used as a new kind of additive to change the morphology and chemical properties of the membranes.

Using LiI nanoparticles as the active material is a promising way to improve the performance of the Li-I2 battery. In this study, a first-principles approach is employed to reveal the reaction mechanism of an ultra-small LiI nanoparticle, represented by a Li14I14 cluster, with and without nanoconfined environment. This study is the first time to report that there are polyiodides longer than I 5 − as intermediate products. For the free Li14I14 cluster, the super-long polyiodides ( I 11 − and I 13 − ) are observed at the deep state of charge (delithiation). However, the super-long chains are converted to a compact I14 cluster at the end of delithiation process. The theoretical open circuit voltage between the I14 and Li14I14 clusters exhibits three plateaus. The highest plateau corresponds to the conversion between the compact I14 cluster and super-long chain-like polyiodides, and the wide medium-voltage plateau is attributed to the transmission between super-long chains and short chains. When the Li14I14 cluster is confined in a (14, 0) single wall carbon nanotube (weight ratio of LiI is 38%), the nanoconfined effect can change the cluster to one-dimensional LiI nanowire. The nanoconfined environment can eliminate the voltage plateau above 3 V, because the nanoconfined effect prohibits the formation of super-long polyiodides and the final charge products are Ix = 2, 3, 5 molecules.

The progress of electronic textiles relies on the development of sustainable power sources without much sacrifice of convenience and comfort of fabrics. Herein, we present a rechargeable textile alkaline Zn microbattery (micro-AZB) fabricated by a process analogous to traditional resist-dyeing techniques. Conductive patterned electrodes are realized first by resist-aided electroless/electrodeposition of Ni/Cu films. The resulting coplanar micro-AZB in a single textile, with an electroplated Zn anode and a Ni0.7Co0.3OOH cathode, achieves high energy density (256.2 Wh kg-1), high power density (10.3 kW kg-1), and stable cycling performances (82.7% for 1500 cycles). The solid-state micro-AZB also shows excellent mechanical reliability (bending, twisting, tailoring, etc.). The improved reversibility and cyclability of textile Zn electrodes over conventional Zn foils are found to be due to the significantly inhibited Zn dendrite growth and suppressed undesirable side reactions. This work provides a new approach for energy-storage textile with high rechargeability, high safety, and aesthetic design versatility.

Novel positively charged nanofiltration membranes were facilely prepared by polydopamine (PDA) deposition followed by crosslinking on the polyethersulfone (PES) ultrafiltration (UF) membrane substrate. Specifically, small molecules DMAPA and 1,3-dibromopropane were separately selected as the bridge agent and crosslinking agent, which can not only realize the moderate crosslinking and densification of the loose structure of the PDA layer, but also further improve the hydrophilicity and positive charges of the PDA layer. Under the optimized conditions of DMAPA concentration (2 g/L), 1,3-dibromopropane concentration (10 wt%) and reaction time (9 h), the composite membrane had the surface pore size as low as 1.1 nm, water contact angle as low as 35.1° and zeta potential as high as +63.8 mV at pH = 6. As a result, the optimized positively charged NF membrane (M3) showed an outstanding permeance up to 15.7 L m−2 h−1 bar−1 while maintaining a high rejection above 95% for MgCl2. Meanwhile, M3 also showed good environmental adaptability when facing complex feeding or operating conditions. This work provided new situation in the design and construction of positive charged NF membranes for high efficiency cation separation.

The physical cues in the extracellular environment play important roles in cancer cell metastasis. However, how metastatic cancer cells respond to the diverse mechanical environments of metastatic sites is not fully understood. Here, substrates with different mechanical properties are prepared to simulate the extracellular mechanical environment of various human tissues. The prostate cancer (PC) cells derived from different cancer metastasis sites show heterogeneity in mechanical response. This heterogeneity mediates two distinct metastasis patterns. High stiffness promotes individual cell migration and proliferation by inducing Yes‐associated protein and tafazzin (YAP/TAZ) nuclear localization in bone metastasis‐derived cells, whereas low stiffness promotes cell migration and proliferation by inducing lymphatic metastasis‐derived cells to form clusters characterized by high expression of CD44. The different metastasis patterns induced by the mechanical properties of the extracellular environment are crucial in the development of PC., Cancer metastasis is essential for cancer deaths. The cancer cells are regulated by the mechanical properties of the metastatic site. The prostate cancer cells derived from different cancer metastasis sites show heterogeneity in mechanical response. The different metastasis patterns induced by the mechanical properties of the extracellular environment are crucial in the development of prostate cancer.

Developing novel nanostructured anode materials for Mg storage plays an important role in improving the performance of magnesium-ion (Mg-ion) batteries. Two-dimensional (2D) metal borides (MBenes) are evaluated as potential anode materials in the present study. Simulation results demonstrate that Cr2B2 is a competitive anode material, which can deliver a maximum theoretical capacity of 853.4 mAh/g with an average open-circuit potential of 0.53 eV versus Mg2+/Mg. In addition, Cr2B2 as anode also can exhibit superior diffusion kinetics due to a low energy barrier of 0.38 eV. Comparing with Cr2B2, Mo2B2 exhibits less but still high Mg storage capacity, with a maximum capacity of 502.1 mAh/g. In addition, Mg diffusion barrier on Mo2B2 is 0.84 eV and the average open-circuit potential is 0.67 V versus Mg2+/Mg, both of which are still comparable to the reported anode materials for Mg-ion batteries.

Metallic anodes in Li/Na–X (X = S, Se, I2) batteries, in which the working mechanism is a conversion reaction, suffer severe corrosion and self-discharge caused by the shuttle effect. Beyond alkali...

Vehicle electrification and stationary energy storage urgently demand improved battery systems with high specific capacity and power density. Herein, we design a novel Li-I2 energy storage system by inserting a nitrogen-doped graphene interlayer between the cathode and the separator. This interlayer allows the electrochemical reaction and pseudo-capacitive faradaic reaction to occur at the same reaction sites and helps the resultant battery achieve high electrochemical performance. The Li-I2 battery constructed with the interlayer can achieve remarkable specific capacity (231.0 mAh g−1 at 2 C), excellent rate capability (up to 100 C), and ultra-long cycling life (5000 cycles). Such an outstanding performance can be attributed to the tri-functions of the interlayer which are to retain the iodine species (such as I-, I2, I3-) in the cathode region to alleviate the shuttle phenomenon, utilise the iodine species to afford remarkable pseudo-capacitive effect for energy storage, and accelerate the kinetic process of active materials to present an excellent rate performance owing to the catalytic effect of nitrogen doping. The concept of the tri-functional interlayer suggests a promising direction for the design of robust and high performance rechargeable Li-I2 batteries.

Sulfonated hyperbranched polyethersulfone (SHBPES)-modified halloysite nanotubes (HNTs), HNT-SHBPES, were synthesized and mixed with polyethersulfone (PES) to prepare hybrid ultrafiltration (UF) membranes via the phase inversion method. Pure PES and PES hybrid membranes mixed with SHBPES and HNTs were also prepared. The HNT-SHBPES showed good compatibility with the PES membrane matrix, and a series of PES/HNT-SHBPES hybrid membranes offered improved porosity, surface mean pore size, hydrophilicity, permeability, and anti-fouling properties. These were mainly attributed to the synergistic effects of hydrophilic -SO3H of SHBPES, porous HNTs, and the tiny interspace between HNT-SHBPES and PES matrix. When 8% HNT-SHBPES was doped into PES casting solution (MHS–8), its pure water flux reached 351.6 L/m2 h—this was nearly 2.2 times that of the pure PES membrane (M–0); its rejection rate remained high primarily due to the occurrence of delayed phase separation in the solidification process and the good compatibility between HNT-SHBPES and PES matrix. This resulted in a relatively dense, uniform, and defect-free surface. Additionally, bovine serum albumin (BSA) and humic acid (HA) were chosen as model contaminants to evaluate the anti-fouling properties of all prepared membranes. After multi-cycles UF experiments, MHS–8 retained a higher flux recovery rate and rejection rate than the other membranes confirming its excellent anti-fouling properties and stable overall performance. This work offers a new possibility for hyperbranched polymer-modified nanomaterials to enhance their compatibility with membrane matrix and improve membrane separation performance.

To develop colorless and soluble polyimide films, a novel dianhydride containing 1,4:3,6-dianhydro-D-mannitol unit, 2,5-bis(3,4-dicarboxyphenoxy)-1,4:3,6-dianhydromannitol dianhydride (IMDA) was synthesized. And two series of polyimides were prepared via a two-step thermal imidization, PI−(1–4) were obtained from IMDA and four kinds of aromatic diamines while PI−(5–7) from IMDA and three kinds of semiaromatic diamines. All the polyimides were readily soluble in common polar solvents and could afford flexible, tough and colorless films with transparency up to 89% at 450 nm. Especially, polyimides simultaneously containing 1,4:3,6-dianhydrohexitol units in diamine and dianhydride exhibited comparable optical and soluble performance with the alicyclic fluorinated ones. Meanwhile, it was certified that 1,4:3,6-dianhydrohexitol fragment in dianhydride was more determinant in solubility and transmittance of polyimides than that in diamine. An overall investigation of these polyimides on thermal, mechanical, morphological, soluble, optical and dielectric properties was presented, and their structure-property relationships were discussed in detail.

Lithium–iodine (Li–I2) batteries are considered a competitive candidate for next-generation electrochemical energy storage devices. The high solubility of I2 in aprotic solvents or aqueous solvent systems and the resulting shuttle effect can lead to the corrosion of metallic Li anodes. The present study employs atomistic scale modeling approaches to understand the interactions between Li surfaces and iodine species. It is found that the metallic Li (100) surface and Li (110) surface are very active to capture I2 molecules and facilitate the dissociation of these molecules. According to the ab initio molecular dynamics simulation, the iodization behavior is dependent on the coverage. When the iodine coverage is only 12.5%, the dissociated I atoms will not destroy the anode surface. As the coverage increases to 100%, a thin LiI layer forms but can be exfoliated from the Li surface, resulting in the irreversible loss of active materials. If the coverage is as high as 200%, a thick LiI film can form on the Li anode and deposit on the Li substrate. How the LiNO3 additive protects the Li–I2 battery anode is also studied in the present work. It is found that O and N atoms from the decomposition of the nitrate diffuse faster than I atoms in the metallic anode. Therefore, a Li oxynitride layer can form between the metallic Li metal and the iodine-containing species, which can cut off the direct interaction between the anode and I2 molecules.

Using Li2S as an active material and designing nanostructured cathode hosts are considered as promising strategies to improve the performance of lithium-sulfur (Li-S) batteries. In this study, the reaction mechanisms during the delithiation of nanoconfined Li2S as an active material, represented by a Li20S10 cluster, are examined by first-principles based calculations and analysis. Local reduction and disproportionation reactions can be observed although the overall delithiation process is an oxidation reaction. Long-chain polysulfides can form as intermediate products; however they may bind to insoluble S2-via Li atoms as mediators. Activating the charging process only requires an overpotential of 0.37 V if using Li20S10 as the active material. Sulfur allotropes longer than cyclo-S8 are observed at the end of the charge process. Although the discharge voltage of Li20S10 is only 1.27 V, it can still deliver an appreciable theoretical energy density of 1480 W h kg-1. This study also suggests that hole polarons, in Li20S10 and intermediate products, can serve as carriers to facilitate charge transport. This work provides new insights toward revealing the detailed reaction mechanisms of nanoconfined Li2S as an active material in the Li-S battery cathode.

Electrode host materials play a critical role in determining the electrochemical performance of the energy storage devices such as alkali metal-ion batteries. Cathode host materials are expected to provide good electronic and ionic conductivity, improved specific capacity and high discharge voltage. Two-dimensional (2D) transition metal dichalcogenides are competitive candidates as cathode materials due to their unique structure which can enhance ion diffusion and storage. In this study, a first-principles approach is used to investigate the H-ScO2 monolayer as the cathode host material for alkali metal-ion batteries. It is found that the H-ScO2 monolayer can deliver capacities of 348 mA h g−1, 348 mA h g−1 and 435 mA h g−1 for Li, Na and K storage, respectively, when the cutoff voltage of the discharge process is set to 1 V. During the discharge process, the averaged open circuit voltages are 4.15 V, 3.29 V and 2.89 V for Li-ion, Na-ion and K-ion batteries, respectively. The diffusion barriers of alkali metal atoms on the ScO2 monolayer are less than 0.43 eV. It can be inferred that the ScO2 monolayer is helpful for achieving high-voltage and high-capacity batteries with fast diffusion kinetics. Although the pristine H-ScO2 monolayer is a semiconductor, intermediate products during the discharge process always show half-metallic and metallic properties, which is also beneficial for increasing the electrical conductivity of the cathode.

The recently emerging renewable energy industry has boosted a research hot in searching for bifunctional electrocatalysts for water splitting. CoSe2, as one of transition-metal chalcogenides, has attracted particular attention because of its abundant resource, low cost, high efficiency and stability. However, further enhancing catalytic activity of CoSe2 to meet the large-scale application requirements of hydrogen energy remains an important challenge. Herein, three-dimension (3D) Mo-doped porous CoSe2 nanosheet array was directly formed on commercial Ni foam (Mo-CoSe2 NS@NF) electrode through a three-step process including electrodeposition, hydrothermal and subsequent selenylation. Systematically experimental research and density functional theory calculations confirmed that, based on active site and intermediate modulation effect of Mo doping, the obtained 3D Mo-CoSe2 NS@NF electrodes were provided with enlarged electrochemical active surface area, improved charge transport capability and significantly optimized binding energy for active intermediates of the potential-limiting step, thus exhibiting remarkably boosted bifunctional electrocatalytic ability with a low overpotential of 89 and 234 mV to drive a current density of 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media, respectively. When the Mo-CoSe2 NS@NF electrode was employed as both a cathode and an anode, an advanced water electrolyzer was fabricated, and a 10 mA cm−2 water splitting current density in 1 M KOH solution could be acquired at a minimal cell voltage of 1.54 V. In addition, we also inferred that the active surface for the OER was O* covered CoSe2, and OER occurred through direct recombination mechanism according to the present first-principles simulation. This work offers an atomistic understanding on the boosted HER and OER electrocatalytical activity of CoSe2 by Mo doping, and develops a promising strategy for exploring advanced low-cost and earth-abundant water splitting electrocatalysts to substitute for the precious-metallic catalysts as well.

Nonaqueous Li-O2 and Na-O2 batteries are promising next-generation energy storage devices due to the outstanding energy density. Nevertheless, the current issue needed to be conquered is the sluggish electrochemical reactions, which can count on the choice of an active catalyst. This work theoretically investigates the two-dimensional (2D) double-layer honeycomb (DLHC) AlP as a cathode catalyst for Li-O2 and Na-O2 batteries. It is found that the DLHC AlP can lead to the O2 dissociation at the specific catalytic site with a low energy barrier. Different electrochemical reduction paths are proposed for understanding the discharge process. It is predicted that LiO2 and Li2O2 are the major products in Li-O2 batteries, and the discharge and charge overpotentials are predicted to be less than 0.68 V; while both NaO2 and Na2O2 are the possible products in Na-O2 batteries, and overpotentials are less than 0.27 V for charge and 0.43 V for discharge. The DLHC AlP can provide strong affinities to intermediate products, and the adsorption causes a local reversible phase transition with the formation of Al-O bonds. Our work suggests the DLHC AlP is a promising catalyst to promote energy efficiency for nonaqueous Li-O2 and Na-O2 batteries.

A novel hydrophilic polyamide, PA-OH containing 1:4;3:6-dianhydro-d-mannitol (isomannide) fragment was synthesized and used as an additive to prepare a series of polyethersulfone (PES)/PA-OH hybrid membranes with different content of PA-OH by phase separation method. And the addition of PA-OH was expected to improve the hydrophilicity, permeability, and antifouling performance of the PES ultrafiltration (UF) membrane. The scanning electron microscopic and atomic force microscopic images showed that the addition of PA-OH greatly changed the morphology of membranes by increasing the porosity, pore size and pore density, and the hydrophilicity was also improved with the increased PA-OH content. Based on the UF experiment, when the PA-OH content was 3%, the fluxes of pure water and bovine serum albumin solution reached 213.1 and 92.6 L m−2 h−1, which were close to 1.5 times and 2 times those of the bare PES membrane, respectively. When the PA-OH content was 5%, the FRR1st reached 85.2%, which was distinctly higher than that of the compared PES/polyethylene glycol5% hybrid membrane of 74.3%. And the FRR2st of the PES/PA-OH5% hybrid membrane was still over 80%, which indicated its long-term antifouling performance. Thus, the PA-OH can be a candidate for the hydrophilic additives.

Capacity fade in lithium-ion batteries largely originates from the undesired electrolyte decomposition, which results in the formation of solid electrolyte interphase (SEI) and the anode surface passivation. In this work, a mesoscale interfacial modeling approach is developed to investigate the formation and growth of the SEI film on a typical graphite based anode over several cycles. It is found that lithium diffusion kinetics in the SEI film significantly affects the SEI growth rate. A lower lithium diffusion barrier leads to a higher growth rate. The present model demonstrates that the SEI thickness is a linear function of the square root of the charging time over long-time cycling. Growth of multicomponent SEI film is also elucidated. It is found that the heterogeneity of the SEI film may lead to instability in lithium ion concentration distribution.

Poor electronic conductivity of bulk lithium sulfide (Li2S) is a critical challenge for the debilitating performance of the lithium–sulfur battery. This study focuses on investigating the thermodynamic and kinetic properties of native defects in Li2S based on a first-principles approach. It is found that the hole polaron p+ can form in Li2S by removing a 3p electron from an S2– anion. The p+ diffusion barrier is only 90 meV, which is much lower than the Li vacancy (VLi–) diffusion barrier. Hence p+ has the potential to serve as a charge carrier in the discharge product. Once the vacancy–polaron complex (VLi––2p+) forms, the charge transport will be hindered due to the relatively higher diffusion barrier of the complex. Heteroatom dopants, which can decrease the p+ formation energy and increase VLi– formation energy, are expected to be introduced to the discharge product to improve the electronic conductivity.

Two-dimensional materials are competitive candidates as cathode materials in lithium–sulfur batteries for immobilizing soluble polysulfides and mitigating the shuttle effect. In this study, a mesoscale modeling approach, which combines first-principles simulation and kinetic Monte Carlo simulation, is employed to evaluate titanium silicide (Ti2Si and TiSi2) monolayers as potential host materials in lithium–sulfur batteries. It is found that the Ti2Si monolayer has much stronger affinities to Li2S x (x = 1, 2, 4) molecules than does the TiSi2 monolayer. Also, Ti2Si can facilitate the dissociation of long-chain Li2S4 to LiS2. On the other hand, TiSi2 can only provide a weak chemical interaction for trapping soluble Li2S4. Therefore, the Ti2Si monolayer can be considered to be the next-generation cathode material for lithium–sulfur batteries. Nevertheless, the strong interaction between Ti2Si and Li2S also causes fast surface passivation. How to control the Li2S precipitation on Ti2Si should be answered by future studies.

In this task, carboxylated polysulfone (PSF-COOH) was achieved by introducing the monomer of phenolphthalin (PPL) containing carboxyl to the molecule backbone of polysulfone (PSF). And a series of PSF-COOH copolymers with different carboxylation degree was synthesized by adjusting the molar (%) of bisphenol A (BPA) and PPL in direct copolymerization method and was prepared as PSF-COOH ultrafiltration membranes via phase separation method. The effect of PPL molar (%) in copolymers on the morphology, hydrophilicity, permeation flux, antifouling and mechanical properties of membranes was investigated by scanning electron microscope (SEM), atomic force microscope (AFM), water contact angle, ultrafiltration experiments and universal testing machine, respectively. The results showed that with the increased carboxyl content in membranes, the hydrophilicity, permeation fluxes and antifouling properties of membranes gradually increased. When the molar (%) of PPL to BPA was 100:0, the membrane exhibited the highest pure water flux (329.6 L/m 2 h) and the maximum flux recovery rate (92.5%). When the content of carboxyl in the membrane was 80% or more, after three cycles of BSA solution (1 g/L) filtration, the flux recovery rate was basically constant or showed a slightly increase. Thus, it can achieve the goal of long term usage without compromising flux.

Besides lithium sulfide (Li2S), lithium persulfide (Li2S2) is another solid discharge product in lithium–sulfur (Li–S) batteries. Revealing the charge transport mechanism in the discharge products is important for developing an effective strategy to improve the performance of Li–S batteries. Li2S2 cannot transport free electrons due to its wide bandgap between the valence band maximum (VBM) and conduction band minimum (CBM). However, electron polarons (p–) and hole polarons (p+) can appear in solid Li2S2 due to the unique molecular orbital structure of the S22– anion. The thermodynamic and kinetic properties of native defects are investigated. It is found that negatively charged Li vacancies (VLi–) and p+ are the main native defects with a low formation energy of 0.77 eV. The predominant charge carrier is p+ because p+ has a high mobility. The electronic conductivity related to p+ diffusion is dependent on temperature, and high temperatures are preferred to increase the conductivity.

The cathode surface passivation caused by Li2S precipitation adversely affects the performance of lithium–sulfur (Li–S) batteries. Li2S precipitation is a complicated mesoscale process involving adsorption, desorption and diffusion kinetics, which are affected profoundly by the reactant concentration and operating temperature. In this work, a mesoscale interfacial model is presented to study the growth of Li2S film on carbon cathode surface. Li2S film growth experiences nucleation, isolated Li2S island growth and island coalescence. The slow adsorption rate at small S2– concentration inhibits the formation of nucleation seeds and the lateral growth of Li2S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Li2S nucleation seeds form in such an operating temperature range, thereby facilitating heterogeneous growth and potentially inhibiting the lateral growth of the Li2S film, which m...

As a widely used approach to modify a material's bulk properties, doping can effectively improve electrochemical properties and structural stability of various cathodes for rechargeable batteries, which usually empirically favors a uniform distribution of dopants. It is reported that dopant aggregation effectively boosts the cyclability of a Mg-doped P2-type layered cathode (Na0.67 Ni0.33 Mn0.67 O2 ). Experimental characterization and calculation consistently reveal that randomly distributed Mg dopants tend to segregate into the Na-layer during high-voltage cycling, leading to the formation of high-density precipitates. Intriguingly, such Mg-enriched precipitates, acting as 3D network pillars, can further enhance a material's mechanical strength, suppress cracking, and consequently benefit cyclability. This work not only deepens the understanding on dopant evolution but also offers a conceptually new approach by utilizing precipitation strengthening design to counter cracking related degradation and improve high-voltage cyclability of layered cathodes.

The polysulfide shuttle phenomenon substantially deteriorates the electrochemical performance of lithium-sulfur (Li-S) batteries, resulting in continued self-discharge and capacity fade during cycling. In this study, a mesoscale analysis is presented to explore the mechanisms of self-discharge behavior in the Li-S battery during the resting state. It is found that the self-discharge rate is determined by the sulfur solubility, desorption capability, diffusion kinetics, and reaction rate on the anode surface. Three regimes have been identified: desorption control, diffusion control, and charge transfer control. Correspondingly, strategies are suggested to increase the capacity retention, such as enhancing the binding of sulfur molecules to the host, reducing dissolved sulfur diffusivity, and improving the chemical stability of active materials with a Li metal anode. Furthermore, the use of an interlayer with high diffusion barriers can effectively suppress the self-discharge rate due to the confinement effect.

The sodium-selenium (Na-Se) battery is a competitive candidate as the practical next-generation energy storage device. A Na16Se8 cluster confined within a (10, 10) single-walled carbon nanotube is constructed to reveal the nanoconfinement effect on the reaction mechanism of the Na-Se battery cathode. It is found that the nanoconfinement can enhance the electronic conductivity of Na x≥12Se8 nanostructures because itinerant electrons appear under this condition. During desodiation, polyselenide chains grow longer and the intermediate products become insulators for transferring electrons. However, hole polarons have the potential to act as charge carriers in Na x≤10Se8 nanostructures. The open-circuit voltage profile is plotted, and the voltage window is 1.67 ≤ U ≤ 1 V. After the first charge cycle, the cathode cannot discharge to Na16Se8, but the reversible specific capacity can still arrive at 302 mA h/g of the cathode composite.

Nanofiltration (NF) membrane typically prepared by interfacial polymerization (IP) technology is facing the problems of low permeance and flux-selectivity trade-off effect, which will seriously affect the efficiency of water purification. Here, novel NF membranes with a thin and crumpled polyamide (PA) layer were obtained by introducing low concentration of soluble inorganic salts (≤2 wt%) in the IP process and thermally induced crystallization of inorganic salts in the heat treatment process. The forces generated by the growth of inorganic salt crystals inevitably stretched the nascent and flexible PA layer, and further the inorganic salt crystals can sacrifice themselves in water, contributing to the formation of a thin and rough PA layer with crumpled nanostructure. Using NaCl as an example, the resulting NF membrane exhibited the permeation flux as high as 84 L/m2 h at 4 bar while maintaining a high rejection of 96.2% for Na2SO4. Meanwhile, it is universal for other soluble inorganic salts such as KCl, Na2SO4, KNO3 and CaCl2 to improve the filtration performance of NF membrane. This study is the first to combine the growth of inorganic salt crystals with the morphology regulation of PA active layer in the heat treatment process, which will further expand the research method of NF membrane with efficient water purification.

Transition metal oxides are usually used as catalysts in the air cathode of lithium-air (Li-air) batteries. This study elucidates the mechanistic origin of the oxygen reduction reaction catalyzed by δ-MnO2 monolayers and maps the conditions for Li2O2 growth using a combination of first-principles calculations and mesoscale modeling. The MnO2 monolayer, in the absence of an applied potential, preferentially reacts with a Li atom instead of an O2 molecule to initiate the formation of LiO2. The oxygen reduction products (LiO2, Li2O2, and Li2O molecules) strongly interact with the MnO2 monolayer via the stabilization of Li-O chemical bonds with lattice oxygen atoms. As compared to the disproportionation reaction, direct lithiation reactions are the primary contributors to the stabilization of Li2O2 on the MnO2 monolayer. The energy profiles of (Li2O2)2 and (Li2O)2 nucleation on δ-MnO2 monolayer during the discharge process demonstrate that Li2O2 is the predominant discharge product and that further reduction to Li2O is inhibited by the high overpotential of 1.21 V. Interface structures have been examined to study the interaction between the Li2O2 and MnO2 layers. This study demonstrates that a Li2O2 film can be homogeneously deposited onto δ-MnO2 and that the Li2O2/MnO2 interface acts as an electrical conductor. A mesoscale model, developed based on findings from the first-principles calculations, further shows that Li2O2 is the primary product of electrochemical reactions when the applied potential is smaller than 2.4 V.

The internal shuttle effect caused by polysulfides dissolution and migration negatively impacts lithium–sulfur battery performance. In this work, a mesoscale simulation strategy, which involves atomistic calculation and coarse-grained molecular modeling, is employed to evaluate silicene as a potential cathode host material to immobilize polysulfides. Adsorption energies of insoluble polysulfides (Li2Sx with x = 1, 2) and soluble polysulfide Li2S4 on pristine and doped silicene sheets are calculated. Results show that the adsorption is thermodynamically favorable and N-doped silicene is helpful in trapping intermediate discharge products, Li2S2 and Li2S4. The dissociation and reduction of long-chain polysulfides to short-chain polysulfides are observed. Electronic structure analysis shows that Li2Sx molecules interact with silicene via strong chemical bonds. The atomistic structure evolution of Li2S layer formation on silicene is also investigated in this study. It is found that Li2S (110) layer ...

Manipulating the in-plane defects of metal-nitrogen-carbon catalysts to regulate the electroreduction reaction of CO2 (CO2 RR) remains a challenging task. Here, it is demonstrated that the activity of the intrinsic carbon defects can be dramatically improved through coupling with single-atom Fe-N4 sites. The resulting catalyst delivers a maximum CO Faradaic efficiency of 90% and a CO partial current density of 33 mA cm-2 in 0.1 m KHCO3. The remarkable enhancements are maintained in concentrated electrolyte, endowing a rechargeable Zn-CO2 battery with a high CO selectivity of 86.5% at 5 mA cm-2 . Further analysis suggests that the intrinsic defect is the active sites for CO2 RR, instead of the Fe-N4 center. Density functional theory calculations reveal that the Fe-N4 coupled intrinsic defect exhibits a reduced energy barrier for CO2 RR and suppresses the hydrogen evolution activity. The high intrinsic activity, coupled with fast electron-transfer capability and abundant exposed active sites, induces excellent electrocatalytic performance.

Embedding the fragmented selenium into the micropores of carbon host has been regarded as an effective strategy to change the Li-Se chemistry by a solid-solid mechanism, thereby enabling an excellent cycling stability in Li-Se batteries using carbonate electrolyte. However, the effect of spatial confinement by micropores in the electrochemical behavior of carbon/selenium materials remains ambiguous. A comparative study of using both microporous (MiC) and mesoporous carbons (MeC) with narrow pore size distribution as selenium hosts is herein reported. Systematic investigations reveal that the high Se utilization rate and better electrode kinetics of MiC/Se cathode than MeC/Se cathode may originate from both its improved Li+ and electronic conductivities. The small pore size (

Optimizing the activity of layered molybdenum disulfide (MoS2) toward hydrogen evolution reaction (HER) process is generally achieved by improving the electrical transport, intrinsic activity, and/or the number of active sites. However, simultaneously coupling these factors to achieve remarkable MoS2-based electrocatalysts has been seldom reported. Herein, we report a facile approach to the defect-rich one-dimensional MoS2 hierarchical architecture (1D-DRHA MoS2), which synergistically integrate the advantageous structural features of rich defects and one-dimensional hierarchal morphology. Toward HER process, the 1D-DRHA MoS2 electrocatalyst exhibited an overpotential of 119 mV at 10 mA cm−2, a Tafel slope of 50.7 mV dec-1, accompanied by an excellent stability. Notably, the activity is competitive to the state-of-the-art MoS2-based electrocatalysts for HER. The combination of experimental evidences and density functional theory calculations demonstrated the incorporation of rich defects and one-dimensional hierarchical structure improved electric conductivity, intrinsic activity, and active sites, which together accounted for the boosted HER performance.

The shuttle effect and poor conductivity of the discharge products are among the primary impediments and scientific challenges for lithium–sulfur batteries. The lithium–sulfur battery is a complex energy storage system, which involves multistep electrochemical reactions, insoluble polysulfide precipitation in the cathode, soluble polysulfide transport, and self-discharge caused by chemical reactions between polysulfides and Li metal anode. These phenomena happen at different length and time-scales and are difficult to be entirely gauged by experimental techniques. In this paper, we reviewed the multiscale modeling studies on lithium–sulfur batteries: (1) the atomistic simulations were employed to seek alternative materials for mitigating the shuttle effect; (2) the growth kinetics of Li2S film and corresponding surface passivation were investigated by the interfacial model based on findings from atomistic simulations; (3) the nature of Li2S2, which is the only solid intermediate product, was revealed by the density functional theory simulation; and (4) macroscale models were developed to analyze the effect of reaction kinetics, sulfur loading, and transport properties on the cell performance. The challenge for the multiscale modeling approach is translating the microscopic information from atomistic simulations and interfacial model into the meso-/macroscale model for accurately predicting the cell performance.

Traditional Fourier transform infrared (FTIR) spectroscopy has been recognized as a valuable method to characterize and classify kinds of microorganisms. In this study, combined with multivariate statistical analysis, synchrotron radiation-based FTIR (SR-FTIR) microspectroscopy was applied to identify and discriminate ten foodborne bacterial strains. Our results show that the whole spectra (3000–900 cm−1) and three subdivided spectral regions (3000–2800, 1800–1500 and 1200–900 cm−1, representing lipids, proteins and polysaccharides, respectively) can be used to type bacteria. Either the whole spectra or the three subdivided spectra are good for discriminating the bacteria at levels of species and subspecies, but the whole spectra should be given preference at the genus level. The findings demonstrate that SR-FTIR microspectroscopy is a powerful tool to identify and classify foodborne pathogenic bacteria at the genus, species and subspecies level.

Human mesenchymal stem cells (hMSCs) have been used as an ideal in vitro model to study human adipogenesis. However, little knowledge of the early stage differentiation greatly hinders our understanding on the mechanism of the adipogenesis processes. In this study, synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy was applied to track the global structural and compositional changes of lipids, proteins and nucleic acids inside individual hMSCs along the time course. The multivariate analysis of the SR-FTIR spectra distinguished the dynamic and significant changes of the lipids and nucleic acid at early differentiation stage. Importantly, changes of lipid structure during early days (Day 1–3) of differentiation might serve as a potential biomarker in identifying the state in early differentiation at single cell level. These results proved that SR-FTIR is a powerful tool to study the stem cell fate determination and early lipogenesis events.

Understanding interfacial phenomena such as ion and electron transport at dynamic interfaces is crucial for revolutionizing the development of materials and devices for energy-related applications. Moreover, advances in this field would enhance the progress of related electrochemical interfacial problems in biology, medicine, electronics, and photonics, among others. Although significant progress is taking place through in situ experimentation, modeling has emerged as the ideal complement to investigate details at the electronic and atomistic levels, which are more difficult or impossible to be captured with current experimental techniques. Among the most important interfacial phenomena, side reactions occurring at the surface of the negative electrodes of Li-ion batteries, due to the electrochemical instability of the electrolyte, result in the formation of a solid-electrolyte interphase layer (SEI). In this work, we briefly review the main mechanisms associated with SEI reduction reactions of aprotic organic solvents studied by quantum mechanical methods. We then report the results of a Kinetic Monte Carlo method to understand the initial stages of SEI growth.

The precipitation of lithium sulfide (Li2S) on the Li metal anode surface adversely impacts the performance of lithium-sulfur (Li-S) batteries. In this study, a first-principles approach including density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations is employed to theoretically elucidate the Li2S/Li metal surface interactions and the nucleation and growth of a Li2S film on the anode surface due to long-chain polysulfide decomposition during battery operation. DFT analyses of the energetic properties and electronic structures demonstrate that a single molecule adsorption on Li surface releases energy forming chemical bonds between the S atoms and Li atoms from the anode surface. Reaction pathways of the Li2S film formation on Li metal surfaces are investigated based on DFT calculations. It is found that a distorted Li2S (111) plane forms on a Li(110) surface and a perfect Li2S (111) plane forms on a Li(111) surface. The total energy of the system decreases along the reaction pathway; hence Li2S film formation on the Li anode surface is thermodynamically favorable. The calculated difference charge density of the Li2S film/Li surface suggests that the precipitated film would interact with the Li anode via strong chemical bonds. AIMD simulations reveal the role of the anode surface structure and the origin of the Li2S formation via decomposition of Li2S8 polysulfide species formed at the cathode side and dissolved in the electrolyte medium in which they travel to the anode side during battery cycling.