Preparation of environment-friendly solid epoxy resin with high-toughness via one-step banburying.

Solid epoxy resin is highly desired in adhesives, electronic materials and coatings due to the attractive characteristics of solvent-free, highly efficient utilization and convenient storage and transportation. However, the challenges remain in fabricating high-toughness solid epoxy resin through a facile and efficient way. Here, a high-performance environment-friendly solid epoxy resin was fabricated by employing maleic anhydride grafted ethylene-vinyl acetate copolymer (EVA-g-MAH) as the flexibilizer via one-step banburying method. The results showed that the modified epoxy resin maintained a high glass transition temperature (T g) and thermal stability, while its impact strength, tensile toughness and flexural toughness were significantly increased compared with the neat epoxy resin. The impact strength, tensile toughness and flexural toughness of R-EM10 are improved 138%, 195% and 149%, respectively. The EVA-g-MAH was introduced in the epoxy matrix as a separate phase to increase toughness via transfer stress and dissipated energy. The attractive properties of this facile fabrication process and the high-toughness, as well as the environment-friendly performance make this solid epoxy highly promising for large-scale industrial application.

Rational design of cobalt-nickel double hydroxides for flexible asymmetric supercapacitor with improved electrochemical performance.

Rational design of micro-nano morphology and suitable crystalline structure are highly desired for metal hydroxides to achieve overall high-performance in the advanced electrodes for flexible supercapacitors. Herein, a novel wisteria flower-like microstructure of cobalt-nickel double hydroxide (CoNi-DH) is successfully constructed on carbon cloth (CC) using an in-situ hydrolysis-induced exchange process between hydroxide ions and organic ligands of the Co-MOF in four different kinds of solutions containing Ni2+. The as-prepared wisteria flower-like microstructure grown on CC shows vertically aligned arrays with high specific area and abundant active sites, which not only guarantee the CoNi-DH active materials to be thoroughly exposed in the electrolyte, resulting in highly effective pseudocapacitive energy storage, but also are beneficial to rapid and reversible redox kinetics and thus give rise to high-rate capability. In addition, compared to Ni(NO3)2, NiCl2, and Ni(CH3COO)2 solutions, the Ni2SO4 solution is found to facilitate the formation of the most regular morphology and the largest interlayer spacing on (003) plane of the layered nickel hydroxide phase in the resultant CoNi-DH. As a result, the optimal CoNi-DH-S@CC (CoNi-DH prepared in Ni2SO4) serves as an advanced electrode to show high-rate capability (only 13% Cs decay after a 15-fold current elevation) and a superior specific capacity (Cs) of 929.4 C g-1, which remarkably exceeds those of CoNi-DH-N (823.1 C g-1, in Ni(NO3)2), CoNi-DH-Cl (798.4 C g-1, in NiCl2), CoNi-DH-C (803.8 C g-1, in Ni(CH3COO)2), and other similar metal hydroxides. Moreover, with this CoNi-DH-S electrode as the positive electrode, the as-prepared asymmetric supercapacitor (ASC) delivers an impressive capacity of 204.8 C g-1, a superior energy density of 42.5 Wh kg-1, and satisfactory cycle life (81.5% reservation after 7500 cycles). As a proof-of-concept application, a quasi-solid-state ASC is further successfully fabricated based on the CoNi-DH-S electrode to exhibit encouraging application potential.

Electrochemically Stable Cobalt⁻Zinc Mixed Oxide/Hydroxide Hierarchical Porous Film Electrode for High-Performance Asymmetric Supercapacitor.

Construction of electrochemically stable positive materials is still a key challenge to accomplish high rate performance and long cycling life of asymmetric supercapacitors (ASCs). Herein, a novel cobalt⁻zinc mixed oxide/hydroxide (CoZn-MOH) hierarchical porous film electrode was facilely fabricated based on a cobalt⁻zinc-based metal⁻organic framework for excellent utilization in ASC. The as-constructed hierarchical porous film supported on conductive Ni foam possesses a rough surface and abundant macropores and mesopores, which allow fast electron transport, better exposure of electrochemically active sites, and facile electrolyte access and ion diffusion. Owing to these structural merits in collaboration, the CoZn-MOH electrode prepared with a zinc feeding ratio up to 45% at 110 min of heating time (CoZn-MOH-45-110) exhibited a high specific capacitance of 380.4 F·g-1, remarkable rate capability (83.6% retention after 20-fold current increase), and outstanding cycling performances (96.5% retention after 10,000 cycles), which exceed the performances of similar active electrodes. Moreover, an ASC based on this CoZn-MOH-45-110 electrode exhibited a high specific capacitance of 158.8 F·g-1, an impressive energy density of 45.8 Wh·kg-1, superior rate capability (83.1% retention after 50-fold current increase), and satisfactory cycling stability (87.9% capacitance retention after 12,000 cycles).

Facile Activation of Commercial Carbon Felt as a Low-Cost Free-Standing Electrode for Flexible Supercapacitors.

High cost, low capacitance, and complicated synthesis process are still the key limitations for carbon-negative materials to meet their industrial production and application in high-energy-density asymmetric supercapacitors (ASCs). In this work, we demonstrate the facile preparation of ultrahigh-surface-area free-standing carbon material from low-cost industrial carbon felt (CF) and its application for flexible supercapacitor electrode with outstanding performance. Through a simple freeze-drying-assisted activation method, the as-prepared activated CF (ACF) was endowed with satisfactory flexibility, ultrahigh specific surface area of 2109 m2 g-1, good electric conductivity (311 S m-1), and excellent wettability to aqueous electrolyte. Owing to these merits, the ACF expressed an ultrahigh areal capacitance of 1441 mF cm-2, a high specific capacitance ( Cs) of 280 F g-1 based on the mass of the whole electrode, and an impressive cycling stability (87% retention after 5000 cycles). When applied as a flexible freestanding electrode for MnO2//ACF ASCs, the ACF-based device provided satisfactory areal energy densities of 0.283 and 0.104 mWh cm-2 in aqueous and quasi-solid electrolytes, respectively. The values outperform many previously reported carbon-based electrochemical devices. The low cost of raw material and the facile fabrication process, together with the high electrochemical performance, make our ACF electrode highly applicable for the mass production of flexible energy-storage devices.

Synthesis of NiMn-LDH Nanosheet@Ni3S2 Nanorod Hybrid Structures for Supercapacitor Electrode Materials with Ultrahigh Specific Capacitance.

One of the key challenges for pseudocapacitive electrode materials with highly effective capacitance output and future practical applications is how to rationally construct hierarchical and ordered hybrid nanoarchitecture through the simple process. Herein, we design and synthesize a novel NiMn-layered double hydroxide nanosheet@Ni3S2 nanorod hybrid array supported on porous nickel foam via a one-pot hydrothermal method. Benefited from the ultrathin and rough nature, the well-defined porous structure of the hybrid array, as well as the synergetic effect between NiMn-layered double hydroxide nanosheets and Ni3S2 nanorods, the as-fabricated hybrid array-based electrode exhibits an ultrahigh specific capacitance of 2703 F g-1 at 3 A g-1. Moreover, the asymmetric supercapacitor with this hybrid array as a positive electrode and wood-derived activated carbon as a negative electrode demonstrates high energy density (57 Wh Kg-1 at 738 W Kg-1) and very good electrochemical cycling stability.

Multiple diabetic complications, as well as impaired physical and mental function, are associated with declining balance function in older persons with diabetes mellitus.

OBJECTIVE: To investigate whether there is a difference in balance function between older persons with and without diabetes mellitus (DM), and to identify whether mediating factors, such as diabetic complications, Instrumental Activities of Daily Living (IADL) score, Mini-Mental State Examination (MMSE) score, as well as hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), serum total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL), are associated with balance function in older persons with DM. METHODS: In this cross-sectional study, a total of 208 older persons were divided into a DM group (n=80) and a control group who did not have DM (n=128). Balance function was evaluated with the Tinetti performance-oriented mobility assessment (POMA), which includes balance and gait subscales. Activities of daily living (ADL), IADL, and the MMSE were also measured. Fall incidents in last 12 months, the use of walking aids, fear of falling, comorbidities, and polypharmacy were recorded. Diabetic complications were recorded, and HbA1c, FPG, TC, TG, and LDL were measured in the patients of the DM group. RESULTS: Fall incidents in last 12 months were higher in the DM group than in the control group (P<0.01). POMA score as well as ADL and IADL scores were lower in the diabetic group than the control group (P<0.05). Within the diabetic group, the POMA score was positively related to the ADL score (odds ratio [OR], 11.7; 95% confidence interval [CI], 3.076-44.497; P<0.01), IADL score (OR, 16.286; 95% CI, 4.793-55.333; P<0.01), and MMSE score (OR, 10.524; 95% CI, 2.764-40.074; P<0.01), but was negatively related to age (OR, 7.707; 95% CI, 2.035-29.185; P<0.01) and diabetic complication (OR, 6.667; 95% CI, 2.279-19.504; P<0.01). Also, within the DM group, the decreased POMA score was associated with multiple diabetic complications (OR, 5.977; 95% CI, 1.378-25.926; P<0.05), decreased IADL score (OR, 10.288; 95% CI, 2.410-43.915; P<0.01), and MMSE score (OR, 13.757; 95% CI, 2.556-74.048; P<0.01). CONCLUSION: Multiple diabetic complications, lower MMSE, ADL, and IADL scores were associated with declining balance function in the older persons with DM. These findings can alert physicians to detect and intervene earlier on declining balance in older persons with DM.