Negatively Charged Laponite Sheets Enhanced Solid Polymer Electrolytes for Long-Cycling Lithium-Metal Batteries.

Solid polymer electrolytes suffer from the low ionic conductivity and poor capability of suppressing lithium dendrites, which have greatly hindered the practical application of solid-state lithium-metal batteries. Here, we report a novel laponite sheet (LS) with a large negatively charged surface as an additive in a solid composite electrolyte (poly(ethylene oxide)-LS) to rearrange the lithium-ion environment and enhance the mechanical strength of the electrolytes (PEO-LS). The strong electrostatic regulation of laponite sheets assists the dissociation of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and constructs multiple transport channels for free lithium ions, achieving a high ionic conductivity of 1.1 × 10-3 S cm-1 at 60 °C. Furthermore, LS facilitates the in situ formation of a LiF-rich interface because of the boosting TFSI- anion concentration, which significantly suppresses lithium dendrites and prevents short circuit. As a result, the assembled LiFePO4|PEO-LS|Li battery demonstrates a long cycle life of over 800 cycles and a high Coulombic efficiency of 99.9% at 1C and 60 °C. When paired with a high-voltage NCM811 cathode, the battery also demonstrates excellent cycling stability and rate capability.

Controllable Transition Metal-Directed Assembly of [Mo2O2S2]2+ Building Blocks into Smart Molecular Humidity-Responsive Actuators.

Smart molecular actuators have become a cutting-edge theme due to their ability to convert chemical energy into mechanical energy under external stimulations. However, realizing actuation at the molecular level and elucidating the mechanisms for actuating still remain challenging. Herein, we design and fabricate a novel nanoscaled polyoxometalate-based humidity-responsive molecular actuator {Bi8Mo48} through the assembly of [Mo2O2S2]2+ units, transition metals, and flexible phosphonic acid ligands. {Bi8Mo48} exhibits a semi-flexible cage-like architecture with oxygen-rich surfaces and highly negative charges 72-. The nanoscaled molecular actuator shows reversible expansion and contraction behavior under humidity variations due to lattice expansion and contraction induced by hydrogen bonding and solvation interactions between {Bi8Mo48} and water molecules. Molecular dynamics simulation was further employed to study these processes, which provides a fundamental understanding for the mechanism of humidity actuation at the molecular level.

Surface-Mediated Construction of an Ultrathin Free-Standing Covalent Organic Framework Membrane for Efficient Proton Conduction.

As a new class of crystalline porous organic materials, covalent organic frameworks (COFs) have attracted considerable attention for proton conduction owing to their regular channels and tailored functionality. However, most COFs are insoluble and unprocessable, which makes membrane preparation for practical use a challenge. In this study, we used surface-initiated condensation polymerization of a trialdehyde and a phenylenediamine for the synthesis of sulfonic COF (SCOF) coatings. The COF layer thickness could be finely tuned from 10 to 100 nm by controlling the polymerization time. Moreover, free-standing COF membranes were obtained by sacrificing the bridging layer without any decomposition of the COF structure. Benefiting from the abundant sulfonic acid groups in the COF channels, the proton conductivity of the SCOF membrane reached 0.54 S cm-1 at 80 °C in pure water. To our knowledge, this is one of the highest values for a pristine COF membrane in the absence of additional additives.

Precise Molecular-Level Modification of Nafion with Bismuth Oxide Clusters for High-performance Proton-Exchange Membranes.

Fabricating proton exchange membranes (PEMs) with high ionic conductivity and ideal mechanical robustness through regulation of the membrane microstructures achieved by molecular-level hybridization remains essential but challenging for the further development of high-performance PEM fuel cells. In this work, by precisely hybridizing nano-scaled bismuth oxide clusters into Nafion, we have fabricated the high-performance hybrid membrane, Nafion-Bi12 -3 %, which showed a proton conductivity of 386 mS cm-1 at 80 °C in aqueous solution with low methanol permeability, and conserved the ideal mechanical and chemical stabilities as PEMs. Moreover, molecular dynamics (MD) simulation was employed to clarify the structural properties and the assembly mechanisms of the hybrid membrane on the molecular level. The maximum current density and power density of Nafion-Bi12 -3 % for direct methanol fuel cells reached to 432.7 mA cm-2 and 110.2 mW cm-2 , respectively. This work provides new insights into the design of versatile functional polymer electrolyte membranes through polyoxometalate hybridization.

Syntheses of cucurbit[6]uril-based metal-organic rotaxane networks by the anion regulation strategy and their proton conduction properties.

Two new cucurbit[6]uril (CB[6])-based metal-organic rotaxane networks (MORNs) were successfully obtained by tuning the coordination sphere of metal copper clusters. Compounds 1 and 2 exhibited relatively high proton conductivity at 85 °C and 97% relative humidity (RH), providing great promise for fuel cell electrolyte materials.

Calix[4]resorcinarene-based [Co16] coordination cages mediated by isomorphous auxiliary ligands for enhanced proton conduction.

We herein propose a design assembly of calix[4]resorcinarene-based proton-conductive [Co16] coordination cages (1-SO3H and 1-OH) by carefully mediating the acidic sites of isomorphous auxiliary ligands. Markedly, 1-SO3H exhibits a proton conductivity that increased about 1 order of magnitude relative to its counterpart 1-OH, reaching 1.35 × 10-2 S cm-1 at 90 °C and under 98% relative humidity.

A bismuth oxide/graphene oxide nanocomposite membrane showing super proton conductivity and low methanol permeability.

Proton exchange membrane fuel cells are still limited as state-of-art proton exchange membranes perform poorly at high and low temperature and are easily damaged by harsh electrochemical conditions such as reactive peroxide species. One effective solution to this issue is to develop new types of proton conductive materials that are capable of working in a broad temperature range. A simple vacuum-assisted filtration method is employed to obtain a well-ordered new proton-conducting membrane by immobilizing nanosized bismuth oxide clusters [H6Bi12O16] (NO3)10·6(H2O) {H6Bi12O16} onto graphene oxide (GO) supports (named as {H6Bi12O16}/GO). {H6Bi12O16}/GO is stable in acidic media and has high proton conductivity over the temperature range from -40 to 80 °C. The proton conductivity of the {H6Bi12O16}/GO membrane is 0.564 S cm-1 at 80 °C in aqueous solution (in plane), and 0.1 S cm-1 at 80 °C and 97% RH (out of plane), respectively. Without loss of high proton conductivity, the membrane also exhibited 100-fold lower methanol permeability than a Nafion 117 membrane. Moreover, {H6Bi12O16}/GO displayed good catalytic decomposition of hydrogen peroxide and superior humidity response and recovery properties. These advantages mean that {H6Bi12O16}/GO holds great promise as a solid-state electrolyte that can potentially be applied in energy conversion devices in the future.

Acute arterial embolism of left lower extremity caused by paradoxical embolism in Ebstein's anomaly: A case report.

INTRODUCTION: Ebstein's anomaly is a benign and stable congenital heart disease for asymptomatic patients. Despite a low incidence of Ebstein's anomaly (EA), patients' quality of life can be badly affected by EA without positive surgical intervention. Especially EA is associated with other congenital heart disease, such as the atrial septal defect, patent foramen ovale, and arterial embolism exclude other reasons, it is often considered to be the consequence of paradoxical embolism, and surgical intervention must be conducted. CASE REPORT: An 11-year-old girl falling off the bed suffered pain from left lower extremity. Echocardiographic evaluation revealed an EA, severe tricuspid regurgitation, and secundum atrial septal defect. Both left leg amputation and cardiac surgery were conducted after recovery. Under the condition of anesthesia cardiopulmonary bypass extracorporeal circulation, atrial septal defect repair and Cone reconstruction of the tricuspid valve were performed. Patient recovered well and left hospital smoothly. DISCUSSION: EA is a rare and complex congenital cardiac malformation. There are about 80% to 90% of EA patients with combined atrial septal defect and patent foramen ovale. Sudden arterial occlusion is very rare especially in childhood. When thoracic roentgenoscopy, arterial blood gas analysis, coagulation test, and echocardiographic of lower extremity deep venous system are all normal, one should consider the possibility of a paradoxical embolism. If patients have the paradoxical embolism or worsening tricuspid regurgitation, the most suitable therapeutic regimen should be chosen according to patients' condition. With surgical techniques and methods renewed continuously, cone reconstruction of the tricuspid valve has been confirmed in clinical trials, which can use its own tissues to form not only central bloodstream, but also the coaption between leaflet and leaflet.

The modified cone reconstruction in the treatment of Ebstein's anomaly: Case reports.

RATIONALE: To investigate the early and mid-term clinical outcomes of the modified cone reconstruction in the treatment of Ebstein's anomaly (EA) which provide appropriate surgical treatment for clinical and reduce the incidence of re-operation and valve replacement. PATIENT CONCERNS: Clinical data of 18 consecutive patients with EA in our hospital between May 2008 and August 2015 were analyzed retrospectively. All patients were diagnosed by echocardiography. Among these patients, according to New York Heart Association functional grade, there were 12 patients with grade II cardiac function and 6 patients with grade III. All patients had severe tricuspid regurgitation grade. DIAGNOSES: All patients were diagnosed EA. One case was with acute arterial embolism and amputation of left lower extremity caused by paradoxical embolism of combined secundum atrial septal defect. INTERVENTIONS: The modified cone reconstruction in the treatment of EA of the tricuspid valve uses its own tissues to form not only central bloodstream, but also the coaption between 2 leaflets. For those patients whose anterior leaflet developed poor and smaller, the valve leaflet was widened by using autologous pericardial. For all patients, tricuspid annulus were reinforced by autologous pericardial. One case was combined with double-orifice technique due to postoperative poor closure of the tricuspid valve. OUTCOMES: There were 2 cases with arrhythmia, and they returned to normal after medication. The rest patients recovered smoothly with no death. Review of echocardiography: 1 patient with moderate regurgitation, the rest of patients' leaflets coapted well and had no tricuspid stenosis. All cases were followed up postoperatively for 9 to 38 months, and there were 14 patients with grade I cardiac function and 4 patients with grade II. LESSONS: The early and mid-term clinical outcomes of the modified cone reconstruction in the treatment of EA were which can make leaflets coapt and had a strong antiregurgitation ability, reducing the incidence of re-operation, valve replacement, and postoperative mortality.