Rational design of highly active and durable electrocatalysts for oxygen reactions is critical for rechargeable metal–air batteries. Herein, we report the design and development of composite ...electrocatalysts based on transition metal oxide nanocrystals embedded in a nitrogen‐doped, partially graphitized carbon framework. Benefiting from the unique pomegranate‐like architecture, the composite catalysts possess abundant active sites, strong synergetic coupling, enhanced electron transfer, and high efficiencies in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The Co3O4‐based composite electrocatalyst exhibited a high half‐wave potential of 0.842 V for ORR, and a low overpotential of only 450 mV at the current density of 10 mA cm−2 for OER. A single‐cell zinc–air battery was also fabricated with superior durability, holding great promise in the practical implementation of rechargeable metal–air batteries.
Persephone's battery: Bifunctional electrocatalysts with pomegranate‐like architecture were designed and developed, exhibiting high catalytic activity for oxygen reduction and evolution reactions. These catalysts enabled the assembly of high‐performance zinc–air batteries with long cycling durability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The unique TiO2–C/MnO2 core–double-shell nanowires are synthesized for the first time using as anode materials for lithium ion batteries (LIBs). They combine both advantages from TiO2 such as ...excellent cycle stability and MnO2 with high capacity (1230 mA h g–1). The additional C interlayer intends to improve the electrical conductivity. The self-supported nanowire arrays grown directly on current-collecting substrates greatly simplify the fabrication processing of electrodes without applying binder and conductive additives. Each nanowire is anchored to the current collector, leading to fast charge transfer. The unique one-dimensional core–double-shell nanowires exhibit enhanced electrochemical performance with a higher discharge/charge capacity, superior rate capability, and longer cycling lifetime.
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IJS, KILJ, NUK, PNG, UL, UM
A CO2 in water nanoparticle stabilized Pickering emulsion is used to template micrometer sized hollow porous nitrogen doped carbon particles for high rate performance lithium sulfur battery. For the ...first time, nanoparticles serve the dual role of an emulsion stabilizer and a pore template for the shell, directly utilizing in situ generated CO2 bubbles as template for the core. The minimalistic nature of this method does not require expensive surfactants or additional core templates. Upon polymerization of melamine formaldehyde onto CO2, a robust polymer/silica composite shell is formed and transformed into a porous shell upon washing. The micrometer‐sized hollow morphology in combination with its nitrogen rich porous shell demonstrates impressive rate capabilities of 670 and 500 mAh g−1 even at a high rate of 7C and 9C, respectively. This material also possesses excellent cycle durability, exhibiting a low capacity decay of 0.088%/cycle over 300 cycles. Measurement of the shuttle current and impedance provides interesting insight into the polysulfide mass transfer mechanism of hollow structured sulfur hosts.
A gas Pickering emulsion is used to synthesize porous hollow carbon, taking advantage of the dual role of the nanoparticle as both an emulsion stabilizer and a pore template for the shell. Impressive rate performance is observed and investigated, providing valuable insight into the mechanistic benefits of hollow structures for lithium sulfur battery applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A free‐standing sulfonic acid functionalized graphene oxide (fSGO)‐based electrolyte film is prepared and used in an electrochemical gas sensor, an alcohol fuel cell sensor (AFCS), for the detection ...of alcohol. The fSGO electrolyte film‐based AFCS detects ethanol vapor with excellent response, linearity, and sensitivity, since it possesses a high proton conductivity (58 mS cm−1 at 55 °C). An ethanol detection limit level as low as 25 ppm is achieved and high selectivity for ethanol over acetone is demonstrated. These results do not only show the promising potential of fSGO films in an electrochemical gas sensors, specifically a portable breathalyzer, but also open an alternative pathway to investigate the application of graphene derivatives in the field of gas sensors.
An new type of electrochemical gas sensor, employing a free‐standing film of sulfonic acid functionalized graphene oxide (fSGO) as the solid electrolyte, is developed. Based on the design of alcohol fuel cell sensors (AFCSs), the developed sensor detects alcohol with excellent sensor response, linearity, sensitivity, and selectivity, promising its implementation into portable devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A novel self-supported electrode with long cycling life and high mass loading was developed based on carbon-coated Si nanowires grown in situ on highly conductive and flexible carbon fabric ...substrates through a nickel-catalyzed one-pot atmospheric pressure chemical vapor deposition. The high-quality carbon coated Si nanowires resulted in high reversible specific capacity (∼3500 mA h g–1 at 100 mA g–1), while the three-dimensional electrode’s unique architecture leads to a significantly improved robustness and a high degree of electrode stability. An exceptionally long cyclability with a capacity retention of ∼66% over 500 cycles at 1.0 A g–1 was achieved. The controllable high mass loading enables an electrode with extremely high areal capacity of ∼5.0 mA h cm–2. Such a scalable electrode fabrication technology and the high-performance electrodes hold great promise in future practical applications in high energy density lithium-ion batteries.
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Retrospective case series.
To compare individuals with cervical spinal cord injury (SCI) submitted to transcutaneous electrical diaphragmatic stimulation (TEDS) or a standard weaning protocol (SWP) ...according to the following variables: invasive mechanical ventilation (IMV) time, ventilator weaning time, intensive care unit (ICU) length of stay, and overall hospital length of stay.
Tertiary university hospital. Clinical Hospital of Campinas State University-UNICAMP-Campinas (SP), Brazil.
Retrospective case study investigating ICU patients submitted to tracheostomy due to cervical SCI at a tertiary university hospital (Clinical Hospital of Campinas State University, Brazil). Data were extracted from medical records of patients seen between January 2007 and December 2016. According to medical records, four patients were submitted to TEDS and six to a SWP. Provision of training to patients in the TEDS group was based on consensus medical decision, preference of the physical therapy team and availability of electrostimulation equipment in the ICU.
Total IMV time in the TEDS and the SWP group was 33 ± 15 and 60 ± 22 days, respectively. Length of stay in ICU in the TEDS and the SWP group was 31 ± 18 and 63 ± 45 days, respectively.
TEDS appears to influence the duration of IMV as well as the length of stay in ICU. This physiotherapeutic intervention may be a potentially promising tool for treatment of patients with SCI. However, randomized clinical trials are warranted to support this assumption.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A device that can derive electrical power from the wastewater treatment process is highly desirable and would help to address both the issues of environmental conservation and energy production. A ...novel flow-photocatalytic fuel cell (flow-PFC) was designed, using a burr-like Ag-TiO2 coated photoanode, as a promising alternative to microbial fuel cells (MFCs) for extracting electricity during wastewater treatment. The amount of Ag in the photoanode is controlled to provide optimal visible light activity to the cell in the form of plasmon resonance. When fed with real brewery wastewater, the device provides continuous power generation of 1.85 W m−2 under solar-simulated light, with an average COD removal of 14.8% (532 mg L−1). The flow-PFC provides power densities up to 6 times higher than current MFCs when being fed by wastewater, with comparable if not superior COD removal rates.
•Flow-PFC provides competitive power output and organic removal under solar light.•LSPR-based photocatalysis improves device conductivity and visible light activity.•Photocatalysis and flow design for green, continuous wastewater remediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, polypropylene (PP)/graphene nanoplatelet (GnPs) nanocomposites with very large sized GnPs (∼150 μm) are prepared by melt extrusion followed by injection molding. A number of ...characteristics including thermal, mechanical, and electrical properties are analyzed. DSC shows that the introduction of GnPs facilitates the crystallization of polymer matrix due to a role of GnPs that serves as seeds for heterogeneous nucleation, and XRD reveals that GnPs have a minor induction effect of β crystals. Taking advantage of the large size and high aspect ratio of GnPs, a relatively low percolation threshold of ∼2.99 vol% is obtained with highly increased in-plane and through-plane electrical conductivity. The fitting of experimental data to the percolation theory indicates that GnPs are three dimensionally dispersed within the polymer matrix. The composites exhibit relatively limited mechanical enhancement due to compromising of GnPs by the shear force introduced during the compounding process. Overall, the usage of large sized GnPs is clearly beneficial for obtaining high electrical conductivity with a less amount of filler, but an enhanced dispersion of fillers with controlled morphology is required to achieve great physical and mechanical properties of the PP/GnPs composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Despite the intensive studies of combining silicon (Si) and reduced graphene oxide (rGO), the architecture of Si–rGO composites still needs to be improved to maintain better electrode structure ...integrity and stable solid electrolyte interphase (SEI) upon extensive cycling. Herein, a conductive and protective network with rGO and CVD-implemented carbon is constructed with silicon nanoparticles (Si NPs) embedded inside for the first time. Compared with the regular Si–rGO composite with only Si NPs wrapped by rGO, Si–rGO–C composite successfully improves the electrical conductivity and structure stability. In addition to the wrapping of rGO on Si NPs, the additional carbon layer on the partially exposed Si NPs provides extra protection from fracture during volume change and helps form a stable SEI layer. Carbon rods between rGO flakes function as conductive bridges, creating an effective conductive network on a macroscopic scale. The initial capacity of Si–rGO–C composite reaches 1139mAhg−1 and 894mAhg−1 at 0.1Ag−1 and 1C respectively, and retains 94% of its initial capacity after 300 cycles at 1C. The electrode is stabilized at 770mAhg−1 at 2C during rate performance testing.
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•Si nanoparticles were modified with an in-situ carbon network.•The composite exhibits enhanced rate performance and cycling stability.•This procedure may provide a general method for improving electrode stability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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