Double-skeleton interpenetrating network-structured alkaline solid-state electrolyte enables flexible zinc-air batteries with enhanced power density and long-term cycle life.

The alkaline solid-state electrolytes have received widespread attention for their good safety and electrochemical stability. However, they still suffer from low conductivity and poor mechanical properties. Herein, we report the synthesis of double-network featured hydroxide-conductive membranes fabricated by polyvinyl alcohol (PVA) and chitosan (CS) as the double-skeletons. Then, we implanted quaternary ammonium salt guar hydroxypropyltrimonium chloride (GG) as the OH- conductor for high-performance electrochemical devices. By virtue of the unique stripe-like structure shared from the double skeleton with a high degree of compatibility and stronger hydrogen bond interactions, the polyvinyl alcohol/chitosan-guar hydroxypropyltrimonium chloride (PCG) solid-state electrolytes achieved optimal thermal stability (> 300 °C), mechanical property (∼ 34.15 MPa), dimensional stability (at any bending angle), and high ionic conductivity (13 mS cm-1) and ion mobility number (tion âˆ¼ 0.90) compared with chitosan-guar hydroxypropyltrimonium chloride (CG) and polyvinyl alcohol-guar hydroxypropyltrimonium chloride (PG) electrolyte membrane. As a proof-of-concept application, the "sandwich"-type zinc-air battery (ZAB) assembled using PCG membrane as the electrolyte realized a high open-circuit voltage (1.39 V) and an excellent power density (128 mW cm-2). Notably, in addition to its long-term cycle life (30 h, 2 mA cm-2) and stable discharge plateau (12 h, 5 mA cm-2), it could even enable a flexible ZAB (F-ZAB) to readily power light-emitting diodes (LED) at any bending angle. These merits afford the PCG membrane a promising electrolyte for improving the performance of solid-state batteries.

Bidirectional Voltage Regulation for Integrated Photovoltachromic Device Based on P3HT-Electrochromic Unit and Perovskite/Organic Tandem Solar Cells.

Integrated electrochromic devices powered by photovoltaic cells have evoked a lot of interest due to their promising commercial prospects. However, their application has been restricted by the voltage adaption between the self-powered voltage and the color-changing threshold voltage (Vt). Herein, a strategy of bidirectional voltage regulating is proposed to develop a novel stand-alone integrated photovoltachromic device (I-PVCD), which integrates perovskite/organic tandem solar cells (P/O-TSCs) to drive color-changing process of conjugated poly(3-hexylthiophene) (P3HT) films. To lower the driving-voltage of electrochromic layer, C60 is introduced to decrease the onset oxidation potential of P3HT film, and thus leading to a reduced Vt of 0.70 V benefiting from the enhanced highest occupied molecular orbital level and decreased charge transfer resistance from 67.46 to 49.89 Ω. Simultaneously, PBDB-T is utilized as the hole transport layer in the interconnecting layer of CsPbI2Br/PTB7-Th:IEICO-4F P/O-TSC to improve its open-circuit voltage (Voc) to 1.85 V. Under their synergetic merits, a I-PVCD with a wider self-adaptive voltage range is achieved. This device can undergo fast and reversible chromic transition from beautiful magenta to transparent only under the solar radiation, and demonstrates a coloration efficiency of 351.90 cm2 C-1 and a switching time of 2 s besides its excellent operating reliability.

One-Step Solid-State Synthesis of Ni-Rich Cathode Materials for Lithium-Ion Batteries.

Ni-rich cathodes are expected to serve as critical materials for high-energy lithium-ion batteries. Increasing the Ni content can effectively improve the energy density but usually leads to more complex synthesis conditions, thus limiting its development. In this work, a simple one-step solid-state process for synthesizing Ni-rich ternary cathode materials NCA (LiNi0.9Co0.05Al0.05O2) was presented, and the synthesis conditions were systematically studied. It was found that the synthesis conditions have a substantial impact on electrochemical performance. Furthermore, the cathode materials produced through a one-step solid-state process exhibited excellent cycling stability, maintaining 97.2% of their capacity after 100 cycles at a rate of 1 C. The results show that a one-step solid-state method can successfully synthesize Ni-rich ternary cathode material, which has great potential for application. Optimizing the synthesis conditions also provides valuable ideas for the commercial synthesis of Ni-rich cathode materials.

F-Doped Carbon Nanoparticles-Based Nucleation Assistance for Fast and Uniform Three-Dimensional Zn Deposition.

Aqueous Zn metal-based batteries have considerable potential as energy storage system; however, their application is extremely limited by dendrite development and poor reversibility. In this study, to overcome both challenges, F-doped carbon nanoparticles (FCNPs) are uniformly constructed on substrates (Ti, Zn, Cu, and steel) by a plasma-assisted surface modification, which endows reversible and uniform deposition of Zn metal. FCNPs with high surface charge density act as nucleation assistors and form numerous homogenous Zn nucleation sites toward Zn 3D growth, which improves Zn plating kinetic and results in uniform Zn deposition. Furthermore, the ZnF2  solid electrolyte interface generated during cycling contributes to rapid mass transfer and enhances Zn reversibility, but also suppresses the side reaction. Accordingly, the half-cell of P-Ti coupled with Zn exhibits an average Coulombic efficiency of 99.47% with 500 cycles. The symmetric cell of the P-Zn anode presents a lifespan of over 1500 h at the current density of 5 mA cm-2 . Notably, the cell works for 100 h at 50 mA cm-2 . It is believed that this ingenious surface modification broadens revolutionary methods for uniform metallic deposition, as well as the dendrite-free rechargeable batteries system.

Regulating Surface Oxygen Activity by Perovskite-Coating-Stabilized Ultrahigh-Nickel Layered Oxide Cathodes.

Ultrahigh-Ni layered oxides are proposed as promising cathodes to fulfill the range demand of electric vehicles; yet, they are still haunted by compromised cyclability and thermal robustness. State-of-the-art surface coating has been applied to solve the instability via blocking the physical contact between the electrolyte and the highly active Ni4+ ions on the cathode surface, but it falls short in handling the chemo-physical mobility of the oxidized lattice oxygen ions in the cathode. Herein, a direct regulation strategy is proposed to accommodate the highly active anionic redox within the solid phase. By leveraging the stable oxygen vacancies/interstitials in a lithium and oxygen dual-ion conductor (layered perovskite La4 NiLiO8 ) coating layer, the reactivity of the surface lattice oxygen ion is dramatically restrained. As a result, the oxygen release from the lattice is suppressed, as well as the undesired irreversible phase transition and intergranular mechanical cracking. Meanwhile, the introduced dual-ion conductor can also facilitate lithium-ion diffusion kinetics and electronic conductivity on the particle surface. This work demonstrates that accommodating the anionic redox chemistry by dual-ion conductors is an effective strategy for capacity versus stability juggling of the high-energy cathodes.

Stable Zn Metal Anodes with Limited Zn-Doping in MgF2 Interphase for Fast and Uniformly Ionic Flux.

The practical applications of aqueous Zn metal batteries are currently restricted by the inherent drawbacks of Zn such as the hydrogen evolution reaction, sluggish kinetics, and dendrite formation. To address these problems, herein, a limitedly Zn-doped MgF2 interphase comprising an upper region of pure, porous MgF2 and a lower region of gradient Zn-doped MgF2 is achieved via radio frequency sputtering technique. The porous MgF2 region is a polar insulator whose high corrosion resistance facilitates the de-solvation of the solvated Zn ions and suppression of hydrogen evolution, resulting in Zn metal electrodes with a low interfacial resistance. The Zn-doped MgF2 region facilitates fast transfer kinetics and homogeneous deposition of Zn ions owing to the interfacial polarization between the Zn dopant and MgF2 matrix, and the high concentration of the Zn dopant on the surface of the metal substrate as fine nuclei. Consequently, a symmetric cell incorporating the proposed Zn metal exhibits low overpotentials of ~ 27.2 and ~ 99.7 mV without Zn dendrites over 250 to 8000 cycles at current densities of 1.0 and 10.0 mA cm-2, respectively. The developed Zn/MnO2 full cell exhibits superior capacity retentions of 97.5% and 84.0% with average Coulombic efficiencies of 99.96% after 1000 and 3000 cycles, respectively.

Separation and Recovery of Refined Si from Al-Si Melt by Modified Czochralski Method.

Separation of refined silicon from Al-Si melt is still a puzzle for the solvent refining process, resulting in considerable waste of acid and silicon powder. A novel modified Czochralski method within the Al-Si alloy is proposed. After the modified Czochralski process, a large amount of refined Si particles was enriched around the seed crystalline Si and separated from the Al-Si melt. As for the Al-28%Si with the pulling rate of 0.001 mm/min, the recovery of refined Si in the pulled-up alloy (PUA) sample is 21.5%, an improvement of 22% compared with the theoretical value, which is much larger 1.99 times than that in the remained alloy (RA) sample. The content of impurities in the PUA is much less than that in the RA sample, which indicates that the modified Czochralski method is effective to improve the removal fraction of impurities. The apparent segregation coefficients of boron (B) and phosphorus (P) in the PUA and RA samples were evaluated. These results demonstrate that the modified Czochralski method for the alloy system is an effective way to enrich and separate refined silicon from the Al-Si melt, which provide a potential and clean production of solar grade silicon (SoG-Si) for the future industrial application.

Plasma-Assisted Surface Modification on the Electrode Interface for Flexible Fiber-Shaped Zn-Polyaniline Batteries.

A novel flexible fiber-shaped zinc-polyaniline battery (FZPB) is proposed to enhance the electrochemical performance, mass loading, and stability of polyaniline cathodes. To this end, electron-cyclotron-resonance oxygen plasma-modified carbon fibers are employed. During plasma treatment, on the carbon-fiber surface, O2+ plasma breaks the C-C, C-H, and C-N bonds to form C radicals, while the O2 molecules are broken down to reactive oxygen species (O+, O2+, O2+, and O22+). The C radicals and the reactive oxygen species are combined to homogeneously form oxygen functional groups, such as -OH, -COOH, and -C═O. The surface area and total pore volume of the treated carbon fibers increase as the plasma attacks. During electrodeposition, aniline interacts with the oxygen functional groups to form N-O and N-H bonds and π-π stacking, resulting in a homogeneous and high-loading polyaniline structure and improved adhesion between polyaniline and carbon fibers. In an FZPB, the cathode with plasma-treated carbon fibers and a polyaniline loading of 0.158 mg mgCF-1 (i.e., 2.36 mg cmCF-1) exhibits a capacity retention of 95.39% after 200 cycles at 100 mA g-1 and a discharge capacity of 83.96 mA h g-1 at such a high current density of 2000 mA g-1, which are ∼1.67 and 1.24 times those of the pristine carbon-fiber-based one, respectively. Furthermore, the FZPB exhibits high flexibility with a capacity retention of 86.4% after bending to a radius of 2.5 mm for 100 cycles as a wearable energy device.

Performance evaluation of interfacial polymerisation-fabricated aquaporin-based biomimetic membranes in forward osmosis.

Aquaporins play a promising role in the fabrication of high-performance biomimetic membranes. Interfacial polymerisation is a promising strategy for synthesizing aquaporin-based membranes. In this study, robust and high-performance aquaporin-based biomimetic membranes were successfully fabricated by interfacial polymerisation, and the membrane separation performance and interfacial polymerisation method were systematically evaluated. The effects of modification methods on the performance of aquaporins-based biomimetic membranes, including sodium hypochlorite and thermal post-treatment, protein-to-lipid ratio, liposome concentration and the addition arrangement of aquaporins were also investigated. Morphological observation suggested that the introduced proteoliposomes were completely embedded in the polyamide layer and that their spherical shape was preserved. Sodium hypochlorite post-treatment and thermal treatment were beneficial in improving the water flux and salt rejection of the resultant membrane without sacrificing the aquaporin activity. The biomimetic membranes had a high water flux and salt rejection, which were almost twice that of the control membranes, after aquaporin-based proteoliposomes were incorporated with an appropriated protein-to-lipid ratio and liposome concentration. The addition arrangement of aquaporins during the interfacial polymerisation procedure significantly influence the obtained membrane's structure. Lastly, this article introduces valuable and systematic research on interfacial polymerisation fabricated aquaporin-based biomimetic membranes with outstanding separation performance.

Correction: Performance evaluation of interfacial polymerisation-fabricated aquaporin-based biomimetic membranes in forward osmosis.

[This corrects the article DOI: 10.1039/C9RA00787C.].

Self-Relaxant Superelastic Matrix Derived from C60 Incorporated Sn Nanoparticles for Ultra-High-Performance Li-Ion Batteries.

Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C60 (PC60) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant superelastic characteristics of the PC60 possess the ability to absorb the stress-strain generated by the Sn nanoparticles and can thus alleviate the problem of their extreme volume changes. Meanwhile, well-dispersed dot-like Sn nanoparticles, which are surrounded by a thin SnO2 layer, have suitable interparticle spacing and multilayer structures for alleviating the aggregation of Sn nanoparticles during repeated cycles. The Ohmic characteristic and the built-in electric field formed in the interparticle junction play important roles in enhancing the diffusion and transport rate of Li ions. SPC-50, a Sn-PC60 anode consisting of 50 wt % Sn and 50 wt % PC60, as confirmed by energy-dispersive X-ray spectroscopy analysis, exhibited the highest electrochemical performance. The resulting SPC-50 anode, in a half-cell configuration, exhibited an excellent capacity retention of 97.18%, even after 5000 cycles at a current density of 1000 mA g-1 with a discharge capacity of 834.25 mAh g-1. In addition, the rate-capability performance of this SPC-50 half-cell exhibited a discharge capacity of 544.33 mAh g-1 at a high current density of 10 000 mA g-1, even after the current density was increased 100-fold. Moreover, a very high discharge capacity of 1040.09 mAh g-1 was achieved with a capacity retention of 98.67% after 50 cycles at a current density of 100 mA g-1. Futhermore, a SPC-50 full-cell containing the LiCoO2 cathode exhibited a discharge capacity of 801.04 mAh g-1 and an areal capacity of 1.57 mAh cm-2 with a capacity retention of 95.27% after 350 cycles at a current density of 1000 mA g-1.

ZnO Nanorod Array Modified PVDF Membrane with Superhydrophobic Surface for Vacuum Membrane Distillation Application.

The vacuum membrane distillation (VMD) is a promising technology for lots of applications. To solve the membrane fouling and wetting problems, in this paper, a novel ZnO nanorods 1 H,1 H,2 H,2 H-perfluorodecyltriethoxysilane (PDTS) modified poly(vinylidene fluoride) (PVDF) membrane with a micro/nanoscale hierarchical structure and a superhydrophobic surface has been prepared and applied to the VMD process for distilling highly salty water, for the first time. Among these, a pyrolysis-adhesion method is created to obtain the ZnO seeds and fasten them on the PVDF substrate firmly. The novel modified membrane shows a stable superhydrophobic surface with a water contact angle of 152°, easy cleaning property, excellent thermal and mechanical stability, because of the Cassie's state caused by pocketing much air in the hydrophobized ZnO nanorods, the low surface energy of PDTS coating, and the strong adhesion between ZnO nanorods and PVDF membrane, which has built an ideal structure for VMD application. After 8 h VMD of 200 g L-1 NaCl solution, compared to the virgin PVDF membrane, the novel membrane shows a similar permeate flux but a much higher quality permeated liquid because of its unique antifouling and antiwetting caused by the several microns gap between the feed and the membrane. Due to its easy cleaning property, the novel membrane also exhibits an excellent reusability.

Misdiagnosis of idiopathic hypoparathyroidism: A case report and literature review.

RATIONALE: Idiopathic hypoparathyroidism (IHP) is a rare endocrine condition, which is frequently represented by neuropsychiatric disorders. Hence, the misdiagnosis rate of the disease is rather high, especially for neurologists. PATIENT CONCERNS: We reported a case of misdiagnosed, atypical IHP. In addition, the literature on IHP and the misdiagnosis published in China in the past 2 decades has been reviewed and summarized. DIAGNOSES: Blood testing confirmed that parathyroid hormone (PTH) = 0 pg/mL and the final diagnosis was IHP. INTERVENTIONS AND OUTCOMES: With calcium and vitamin D supplementation, the patient's myasthenia improved significantly, and muscle enzymes returned to normal gradually. One-year follow-up demonstrated that the patient's myasthenia disappeared, and the blood calcium and PTH levels were normal. In addition, the literature on IHP and the misdiagnosis published in China in the past 2 decades has been reviewed and summarized. LESSONS: The misdiagnosis rate of IHP in China was high in the past 2 decades, which might be attributed to the misdiagnosis as epilepsy or mental diseases. A clinician should be able to understand the disease and emphasize the screening of high-risk population, especially for those patients with hypocalcemia, hyperphosphatemia, and increased blood creatine kinase with unknown causes or nontypical clinical symptoms.

Li4SiO4-Based Artificial Passivation Thin Film for Improving Interfacial Stability of Li Metal Anodes.

An amorphous SiO2 (a-SiO2) thin film was developed as an artificial passivation layer to stabilize Li metal anodes during electrochemical reactions. The thin film was prepared using an electron cyclotron resonance-chemical vapor deposition apparatus. The obtained passivation layer has a hierarchical structure, which is composed of lithium silicide, lithiated silicon oxide, and a-SiO2. The thickness of the a-SiO2 passivation layer could be varied by changing the processing time, whereas that of the lithium silicide and lithiated silicon oxide layers was almost constant. During cycling, the surface of the a-SiO2 passivation layer is converted into lithium silicate (Li4SiO4), and the portion of Li4SiO4 depends on the thickness of a-SiO2. A minimum overpotential of 21.7 mV was observed at the Li metal electrode at a current density of 3 mA cm-2 with flat voltage profiles, when an a-SiO2 passivation layer of 92.5 nm was used. The Li metal with this optimized thin passivation layer also showed the lowest charge-transfer resistance (3.948 Ω cm) and the highest Li ion diffusivity (7.06 × 10-14 cm2 s-1) after cycling in a Li-S battery. The existence of the Li4SiO4 artificial passivation layer prevents the corrosion of Li metal by suppressing Li dendritic growth and improving the ionic conductivity, which contribute to the low charge-transfer resistance and high Li ion diffusivity of the electrode.

Pseudocapacitive Characteristics of Low-Carbon Silicon Oxycarbide for Lithium-Ion Capacitors.

Lithium-ion capacitors (LICs) and lithium-ion batteries (LIBs) are important energy storage devices. As a material with good mechanical, thermal, and chemical properties, low-carbon silicon oxycarbide (LC-SiOC), a kind of silicone oil-derived SiOC, is of interest as an anode material, and we have examined the electrochemical behavior of LC-SiOC in LIB and LIC devices. We found that the lithium storage mechanism in LC-SiOC, prepared by pyrolysis of phenyl-rich silicon oil, depends on an oxygen-driven rather than a carbon-driven mechanism within our experimental scope. An investigation of the electrochemical performance of LC-SiOC in half- and full-cell LIBs revealed that LC-SiOC might not be suitable for full-cell LIBs because it has a lower capacity (238 mAh g-1) than that of graphite (290 mAh g-1) in a cutoff voltage range of 0-1 V versus Li/Li+, as well as a substantial irreversible capacity. Surprisingly, LC-SiOC acts as a pseudocapacitive material when it is tested in a half-cell configuration within a narrow cutoff voltage range of 0-1 V versus Li/Li+. Further investigation of a "hybrid" supercapacitor, also known as an LIC, in which LC-SiOC is coupled with an activated carbon electrode, demonstrated that a power density of 156 000 W kg-1 could be achieved while maintaining an energy density of 25 Wh kg-1. In addition, the resulting capacitor had an excellent cycle life, holding ∼90% of its energy density even after 75 000 cycles. Thus, LC-SiOC is a promising active material for LICs in applications such as heavy-duty electric vehicles.

Neutral polyfluoroalkyl substances in the atmosphere over the northern South China Sea.

Neutral Polyfluoroalkyl substances (PFASs) in the atmosphere were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. Four groups of PFASs, i.e., fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAs), fluorooctane sulfonamides (FOSAs) and fluorooctane sulfonamidoethanols (FASEs), were detected in gas samples. FTOHs was the predominant PFAS group, accounting for 95.2-99.3% of total PFASs (ΣPFASs), while the other PFASs accounted for a small fraction of ΣPFASs. The concentrations of ΣPFASs ranged from 18.0 to 109.9 pg m(-3) with an average of 54.5 pg m(-3). The concentrations are comparable to those reported in other marine atmosphere. Higher concentrations of ΣPFASs were observed in the continental-influenced samples than those in other samples, pointing to the substantial contribution of anthropogenic sources. Long-range transport is suggested to be a major pathway for introducing gaseous PFASs into the atmosphere over the northern SCS. In order to further understand the fate of gaseous PFASs during transport, the atmospheric decay of neutral PFASs under the influence of reaction with OH radicals and atmospheric physical processes were estimated. Concentrations of 8:2 FTOH, 6:2 FTOH and MeFBSE from selected source region to the atmosphere over the SCS after long-range transport were predicted and compared with the observed concentrations. It suggests that the reaction with OH radicals may play an important role in the atmospheric decay of PFAS during long-range transport, especially for shorted-lived species. Moreover, the influence of atmospheric physical processes on the decay of PFAS should be further considered.