Dynamically Ion-Coordinated Bipolar Organodichalcogenide Cathodes Enabling High-Energy and Durable Aqueous Zn Batteries.

Bipolar organic cathode materials (OCMs) implementing cation/anion storage mechanisms are promising for high-energy aqueous Zn batteries (AZBs). However, conventional organic functional group active sites in OCMs usually fail to sufficiently unlock the high-voltage/capacity merits. Herein, we initially report dynamically ion-coordinated bipolar OCMs as cathodes with chalcogen active sites to solve this issue. Unlike conventional organic functional groups, chalcogens bonded with conjugated group undergo multielectron-involved positive-valence oxidation and negative-valence reduction, affording higher redox potentials and reversible capacities. With phenyl diselenide (PhSe-SePh, PDSe) as a proof of concept, it exhibits a conversion pathway from (PhSe)- to (PhSe-SePh)0 and then to (PhSe)+ as unveiled by characterization and theoretical simulation, where the diselenide bonds are periodically broken and healed, dynamically coordinating with ions (Zn2+ and OTF-). When confined into ordered mesoporous carbon (CMK-3), the dissolution of PDSe intermediates is greatly inhibited to obtain an ultralong lifespan without voltage/capacity compromise. The PDSe/CMK-3 || Zn batteries display high reversibility capacity (621.4 mAh gPDSe -1), distinct discharge plateau (up to 1.4 V), high energy density (578.3 Wh kgPDSe -1), and ultralong lifespan (12 000 cycles) at 10 A g-1, far outperforming conventional bipolar OCMs. This work sheds new light on conversion-type active site engineering for high-voltage/capacity bipolar OCMs towards high-energy AZBs.

Crowding Effect-Induced Zinc-Enriched/Water-Lean Polymer Interfacial Layer Toward Practical Zn-Iodine Batteries.

Although the meticulous design of functional diversity within the polymer interfacial layer holds paramount significance in mitigating the challenges associated with hydrogen evolution reactions and dendrite growth in zinc anodes, this pursuit remains a formidable task. Here, a large-scale producible zinc-enriched/water-lean polymer interfacial layer, derived from carboxymethyl chitosan (CCS), is constructed on zinc anodes by integration of electrodeposition and a targeted complexation strategy for highly reversible Zn plating/stripping chemistry. Zinc ions-induced crowding effect between CCS skeleton creates a strong hydrogen bonding environment and squeezes the moving space for water/anion counterparts, therefore greatly reducing the number of active water molecules and alleviating cathodic I3- attack. Moreover, the as-constructed Zn2+-enriched layer substantially facilitate rapid Zn2+ migration through the NH2-Zn2+-NH2 binding/dissociation mode of CCS molecule chain. Consequently, the large-format Zn symmetry cell (9 cm2) with a Zn-CCS electrode demonstrates excellent cycling stability over 1100 h without bulging. When coupled with an I2 cathode, the assembled Zn-I2 multilayer pouch cell displays an exceptionally high capacity of 140 mAh and superior long-term cycle performance of 400 cycles. This work provides a universal strategy to prepare large-scale production and high-performance polymer crowding layer for metal anode-based battery, analogous outcomes were veritably observed on other metals (Al, Cu, Sn).

Two-Dimensional Germanium Sulfide Nanosheets as an Ultra-Stable and High Capacity Anode for Lithium Ion Batteries.

Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high-capacity and stable anode materials is still an ongoing challenge. Herein, a facile strategy for the synthesis of ultrathin GeS2 nanosheets with the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two-dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the ion transport, and buffer the volume expansion. Benefiting from these merits, the as-synthesized GeS2 nanosheets deliver high specific capacity (1335 mAh g-1 at 0.15 A g-1 ), extraordinary rate performance (337 mAh g-1 at 15 A g-1 ) and stable cycling performance (974 mAh g-1 after 200 cycles at 0.5 A g-1 ). Importantly, our fabricated Li-ion full cells manifest an impressive specific capacity of 577 mAh g-1 after 50 cycles at 0.1 A g-1 and a high energy density of 361 Wh kg-1 at a power density of 346 W kg-1 . Furthermore, the electrochemical reaction mechanism is investigated by the means of ex-situ high-resolution transmission electron microscopy. These results suggest that GeS2 can use to be an alternative anode material and encourage more efforts to develop other high-performance LIBs anodes.

Ultra-Early Diagnosis of Acute Myocardial Infarction in Rats Using Ultrasound Imaging of Hollow Double-Layer Silica Nanospheres.

Timely diagnosis of acute myocardial infarction (AMI) strongly impacts the survival rate of patients. The authors report the development of a two-shell hollow silica contrast agent useful for ultrasound (US) imaging, which is able to provide ultra-early diagnosis of AMI. To target the characterization of fast blood flow and high blood pressure in the heart, two shells of hollow silica are adopted with opposite polarities, which assemble based on amino and perfluorodecyl silanes. The external amino silane facilitates the attachment of disease-targeted groups, while the internal perfluorodecyl silane provides great US imaging contrast. The material also possesses superior water dispersity, controllable morphology, low toxicity, and biodegradability both in vitro and in vivo, thus promoting its applications in the ultra-early diagnosis of AMI in rats, and is particularly useful for delineation of myocardial necrosis sites.

Efficient room-temperature production of high-quality graphene by introducing removable oxygen functional groups to the precursor.

The excellent solution-processability of graphene oxide (GO) has provided a collection of strategies for the construction of functional graphene assemblies. To improve the performance of graphene-based materials, structurally intact GO should be prepared as a precursor for high-quality graphene; however, solution chemical methods have been constantly challenged by a structural integrity versus fabrication yield trade-off. Here, we report a wet chemical method for the high-efficiency production of a high-quality graphene oxide precursor, with all steps conducted at room-temperature. The functionalization of graphite was performed under temperature and water content control in a concentrated sulfuric acid-potassium permanganate system, and the resulting GO showed a monolayer yield of over 120%. We show that the increased production yield comes from the high functionalization degree and, more interestingly, the functional groups on GO were proven to be removable upon reduction with hydroiodic acid, which produced high-quality graphene-based materials.

Transparent Polymeric Strain Sensors for Monitoring Vital Signs and Beyond.

Wearable sensors that can precisely detect vital signs are highly desirable for monitoring personal health conditions and medical diagnosis. In this paper, we report an ultrasensitive strain sensor consisting of a 150 nm thick highly conductive dimethylsulfoxide-doped poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) sensing layer and an elastic fluorosilicone rubber substrate. This sensor exhibits a high sensitivity at small strains (e.g., gauge factor at 0.6% strain = 280), low limit of detection (<0.2% strain), and excellent repeatability and cycling stability. Therefore, it is promising for practically detecting vital signs, tiny human motions, and sounds. Furthermore, the semitransparent shallow blue color and the soft rubbery substrate make the strain sensor beautiful and comfortable to the human body.

Enrichment and Quantitative Determination of 5-(Hydroxymethyl)-2'-deoxycytidine, 5-(Formyl)-2'-deoxycytidine, and 5-(Carboxyl)-2'-deoxycytidine in Human Urine of Breast Cancer Patients by Magnetic Hyper-Cross-Linked Microporous Polymers Based on Polyionic Liquid.

5-(Hydroxymethyl)-2'-deoxycytidine (5-hmdC), 5-(formyl)-2'-deoxycytidine (5-fodC), and 5-(carboxyl)-2'-deoxycytidine (5-cadC) are crucial intermediate products of the DNA demethylation pathway, which can also act as potential biomarkers reflecting the diagnosis and prognosis in multiple tumors. Detecting 5-hmdC, 5-fodC, and 5-cadC in human urine has various advantages including readily available samples and being noninvasive to patients. However, few works have reported the detection of 5-fodC and 5-cadC due to their trace amounts. Here we developed a novel magnetic hyper-cross-linked microporous polymer (HMP) material based on polyionic liquid (PIL) for the enrichment of 5-hmdC, 5-fodC, and 5-cadC. These magnetic PIL-HMP materials provided specific enrichment superiority for three modified cytidines. After enrichment, the signal intensity of 5-hmdC, 5-fodC, and 5-cadC increased 10-75-fold with lower limits of quantitation (LLOQ) of 0.049, 0.781, and 0.781 ng/mL, respectively. The recoveries were approximately 86.5-95.2% for 5-hmdC, 95.2-107.8% for 5-fodC, and 99.4-102.4% for 5-cadC under the relative standard deviation (RSD) of 0.2-10.3%. Finally, we successfully applied magnetic PIL-HMP materials coupled with high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) in enrichment and quantitative determination of 5-hmdC, 5-fodC, and 5-cadC in human urine of 10 breast cancer patients and 10 healthy people. We found that the level of 5-hmdC decreased in breast cancer patients ( p < 0.05), while the levels of 5-fodC and 5-cadC increased ( p < 0.05, p < 0.01). Our results demonstrated that the levels of metabolic 5-hmdC, 5-fodC, and 5-cadC in human urine are closely related to breast cancer, which could contribute to the clinical diagnosis and investigation of breast cancer and its occurrence and development mechanisms.

Accurate quantification of 5-Methylcytosine, 5-Hydroxymethylcytosine, 5-Formylcytosine, and 5-Carboxylcytosine in genomic DNA from breast cancer by chemical derivatization coupled with ultra performance liquid chromatography- electrospray quadrupole time of flight mass spectrometry analysis.

The DNA demethylation pathway has been discovered to play a significant role in DNA epigenetics. This pathway removes the methyl group from cytosine, which is involved in the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC) by ten-eleven translocation (TET) proteins. Then, 5-hmC can be iteratively oxidized to generate 5-formylcytosine (5-foC) and 5-carboxylcytosine (5-caC). However, 5-hmC, 5-foC, and 5-caC are hardly detected due to their low content. In this study, we have developed a LC-HRMS method coupled with derivatization to accurately and simultaneously quantify 5-mC levels, along with its oxidation products in genomic DNA. Derivatization was carried out using 4-dimethylamino benzoic anhydride, which has been shown to improve separation and enhance the detection sensitivity. Finally, we successfully applied this method towards the quantification of 5-mC, 5-hmC, 5-foC, and 5-caC in genomic DNA isolated from both human breast cancer tissue and tumor-adjacent normal tissue. We show that 5-foC and 5-caC are increased in tumor tissue. In addition, the levels of 5-mC, 5-hmC, 5-foC, and 5-caC measured in tumor tissue versus tumor-adjacent tissue were found to be distinct among different classifications. This suggests that cytosine modifiers could be used as potential biomarkers for determining the stage of development of breast cancer, as well as prognosis.

Organic dispersions of graphene oxide with arbitrary concentrations and improved chemical stability.

We report a simple method that can dissolve graphene oxide (GO) in pure organic solvents (e.g., propylene carbonate) as readily as in pure water to form stable dispersions of single layer GO sheets. The GO sheets dispersed in propylene carbonate exhibited much better structural stability than those in water.

Enhanced detection of amino acids in hydrophilic interaction chromatography electrospray tandem mass spectrometry with carboxylic acids as mobile phase additives.

Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys. In particular, the diacids have better performance than single acids. The proposed mechanism is that the diacid has hydrogen bond interaction with amino acids to reduce their polarity/amphiprotic characteristics. Besides, oxalic acid has been found having better enhancement than phthalic acid by overall consideration. Therefore, we successfully quantified the 15 amino acids in Sepia bulk pharmaceutical chemical by using oxalic acid as the additive.

Reshaping Lithium Plating/Stripping Behavior via Bifunctional Polymer Electrolyte for Room-Temperature Solid Li Metal Batteries.

High-energy rechargeable Li metal batteries are hindered by dendrite growth due to the use of a liquid electrolyte. Solid polymer electrolytes, as promising candidates to solve the above issue, are expected to own high Li ion conductivity without sacrificing mechanical strength, which is still a big challenge to realize. In this study, a bifunctional solid polymer electrolyte exactly having these two merits is proposed with an interpenetrating network of poly(ether-acrylate) (ipn-PEA) and realized via photopolymerization of ion-conductive poly(ethylene oxide) and branched acrylate. The ipn-PEA electrolyte with facile processing capability integrates high mechanical strength (ca. 12 GPa) with high room-temperature ionic conductance (0.22 mS cm-1), and significantly promotes uniform Li plating/stripping. Li metal full cells assembled with ipn-PEA electrolyte and cathodes within 4.5 V vs Li+/Li operate effectively at a rate of 5 C and cycle stably at a rate of 1 C at room temperature. Because of its fabrication simplicity and compelling characteristics, the bifunctional ipn-PEA electrolyte reshapes the feasibility of room-temperature solid-state Li metal batteries.

Sulfur Confined in Sub-Nanometer-Sized 2 D Graphene Interlayers and Its Electrochemical Behavior in Lithium-Sulfur Batteries.

Microspace-confined sulfur molecules as cathodes for lithium-sulfur (Li-S) batteries have shown great significance in both scientific and technical aspects. A study of different microspace-confined sulfur will not only promote the advancement of Li-S batteries but also arouse a wide interest in sulfur chemistry and related applications. Herein, we choose two-dimensional (2D) graphene interlayer as host and construct 2D space-confined sulfur model systems by simple intercalation chemistry of graphite oxide. Two routes, including solvothermal method and interlamellar reaction approach, are developed, and sulfur can be easily intercalated into sub-nanometer-sized graphene interlayers, forming a graphene confined sulfur structure. The 2D space-confined sulfur can work well in a carbonate-based electrolyte and show similar electrochemical behaviors of small sulfur molecules, indicating the special molecular form of sulfur in graphene layers. The 2D space-confined sulfur concept will be helpful for further understanding the electrochemical character of confined sulfur molecules and designing a high-performance sulfur cathode.

Wet Chemistry Synthesis of Multidimensional Nanocarbon-Sulfur Hybrid Materials with Ultrahigh Sulfur Loading for Lithium-Sulfur Batteries.

An optimized nanocarbon-sulfur cathode material with ultrahigh sulfur loading of up to 90 wt % is realized in the form of sulfur nanolayer-coated three-dimensional (3D) conducting network. This 3D nanocarbon-sulfur network combines three different nanocarbons, as follows: zero-dimensional carbon nanoparticle, one-dimensional carbon nanotube, and two-dimensional graphene. This 3D nanocarbon-sulfur network is synthesized by using a method based on soluble chemistry of elemental sulfur and three types of nanocarbons in well-chosen solvents. The resultant sulfur-carbon material shows a high specific capacity of 1115 mA h g(-1) at 0.02C and good rate performance of 551 mA h g(-1) at 1C based on the mass of sulfur-carbon composite. Good battery performance can be attributed to the homogeneous compositing of sulfur with the 3D hierarchical hybrid nanocarbon networks at nanometer scale, which provides efficient multidimensional transport pathways for electrons and ions. Wet chemical method developed here provides an easy and cost-effective way to prepare sulfur-carbon cathode materials with high sulfur loading for application in high-energy Li-S batteries.