Inverse opal-inspired, nanoscaffold battery separators: a new membrane opportunity for high-performance energy storage systems.

The facilitation of ion/electron transport, along with ever-increasing demand for high-energy density, is a key to boosting the development of energy storage systems such as lithium-ion batteries. Among major battery components, separator membranes have not been the center of attention compared to other electrochemically active materials, despite their important roles in allowing ionic flow and preventing electrical contact between electrodes. Here, we present a new class of battery separator based on inverse opal-inspired, seamless nanoscaffold structure ("IO separator"), as an unprecedented membrane opportunity to enable remarkable advances in cell performance far beyond those accessible with conventional battery separators. The IO separator is easily fabricated through one-pot, evaporation-induced self-assembly of colloidal silica nanoparticles in the presence of ultraviolet (UV)-curable triacrylate monomer inside a nonwoven substrate, followed by UV-cross-linking and selective removal of the silica nanoparticle superlattices. The precisely ordered/well-reticulated nanoporous structure of IO separator allows significant improvement in ion transfer toward electrodes. The IO separator-driven facilitation of the ion transport phenomena is expected to play a critical role in the realization of high-performance batteries (in particular, under harsh conditions such as high-mass-loading electrodes, fast charging/discharging, and highly polar liquid electrolyte). Moreover, the IO separator enables the movement of the Ragone plot curves to a more desirable position representing high-energy/high-power density, without tailoring other battery materials and configurations. This study provides a new perspective on battery separators: a paradigm shift from plain porous films to pseudoelectrochemically active nanomembranes that can influence the charge/discharge reaction.

Highly Selective and Scalable Molecular Fluoride Sensor for Naked-Eye Detection.

Fluoride is widely present in nature, and human exposure to it is generally regarded as inevitable. High levels of fluoride intake induce acute and chronic illnesses. To reduce potential harm to the general public, it is essential to create selective fluoride detectors capable of providing a colorimetric response for naked-eye detection without the need for sophisticated equipment. Here, we report a one-pot synthesis of four different diaminomaleonitrile-derived Schiff base sensors. The terephthalaldehyde adduct provided a strong color change visible to the naked eye at a F- concentration level as low as 2 ppm. From the evaluation against other anions, such as CN-, I-, Br-, Cl-, NO3-, PO43-, OAc-, and HSO4-, the molecular sensor displayed a visible color change exclusively upon exposure to fluoride, underscoring exceptional selectivity. As a key intermediate for understanding the mechanism, HF2- was confirmed by 19F nuclear magnetic resonance. Theoretical calculations suggested a deprotonation-triggered bathochromic shift brought about by the unique electronic structure of the sensor. Furthermore, the simple synthetic protocol from economically accessible materials allowed for the preparation of the compound on a large scale, rendering it a highly practical visual fluoride sensor.

Extreme Ion-Transport Inorganic 2D Membranes for Nanofluidic Applications.

Inorganic 2D materials offer a new approach to controlling mass diffusion at the nanoscale. Controlling ion transport in nanofluidics is key to energy conversion, energy storage, water purification, and numerous other applications wherein persistent challenges for efficient separation must be addressed. The recent development of 2D membranes in the emerging field of energy harvesting, water desalination, and proton/Li-ion production in the context of green energy and environmental technology is herein discussed. The fundamental mechanisms, 2D membrane fabrication, and challenges toward practical applications are highlighted. Finally, the fundamental issues of thermodynamics and kinetics are outlined along with potential membrane designs that must be resolved to bridge the gap between lab-scale experiments and production levels.

Enhanced Antioxidant Capacity of Puffed Turmeric (Curcuma longa L.) by High Hydrostatic Pressure Extraction (HHPE) of Bioactive Compounds.

Turmeric (Curcuma longa L.) is known for its health benefits. Several previous studies revealed that curcumin, the main active compound in turmeric, has antioxidant capacity. It has been previously demonstrated that puffing, the physical processing using high heat and pressure, of turmeric increases the antioxidant and anti-inflammatory activities by increasing phenolic compounds in the extract. The current study sought to determine if high hydrostatic pressure extraction (HHPE), a non-thermal extraction at over 100 MPa, aids in the chemical changes and antioxidant functioning of turmeric. 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) analyses were conducted and assessed the content of total phenol compounds in the extract. The chemical changes of curcuminoids were also determined by high performance liquid chromatography (HPLC). Among the three variables of ethanol concentration, pressure level, and treatment time, ethanol concentration was the most influential factor for the HHPE of turmeric. HHPE at 400 MPa for 20 min with 70% EtOH was the optimal extraction condition for the highest antioxidant activity. Compositional analysis revealed that 2-methoxy-4-vinylphenol was produced by puffing. Vanillic acid and ferulic acid content increased with increasing HHPE time. Synergistic effect was not observed on antioxidant activity when the turmeric was sequentially processed using puffing and HHPE.

Dynamics of DNA tumbling in shear to rotational mixed flows: pathways and periods.

The tumbling dynamics of DNA have been examined via experiments and Brownian dynamics (BD) simulations in mixed flows that vary from pure shear to pure rotation. In shear, tumbling pathways and periods agree well with earlier studies; in rotation-dominated flows, a new tumbling pathway is identified and experimentally observed. Based on these results, we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow-type parameter for transition from the shearlike flow regime to the rotation-dominated one.

Selective removal of heavy metal ions by disulfide linked polymer networks.

Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions-copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water.

Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole.

High power density lithium ion battery (HLIB) separators were fabricated for the first time from thermally rearranged poly(benzoxazole-co-imide) (TR-PBOI) nanofibrous membranes coated with TR-PBOI nanoparticles, which show distinct thermal and dimensional stabilities as well as excellent cycle retention and rate capability.

Correction: Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole.

Correction for 'Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole' by Moon Joo Lee et al., Chem. Commun., 2015, 51, 2068-2071.