MXenes and the progress of Li–S battery development - a perspective

Lithium–sulfur (Li–S) battery has attracted tremendous interest owing to its high energy density at affordable costs. However, the irreversible active material loss and subsequent capacity fading caused by the uncontrollable shuttling of polysulfides have greatly hampered its commercial viability. MXenes, a novel class of 2D materials derived from nano-layered MAX phases, have been shown the potential to push the development of sulfur-based batteries to a next level owing to their high conductivity, strong polysulfide affinity and electrocatalytic properties. This perspective article focuses on the possible implications that MXene-based materials will have in the development of advanced sulfur-based batteries and their potential application in different upcoming technologies. In four sections possible developments are outlined which can be reached in the next 10 years, that enable a highly reliable, minimized Li–S battery finally combined with energy harvesters to fabricate autonomous power supplies for the next generation of microscaled devices like meteorological or geotechnical probes, wearable (medical) sensors or other suitable mobile devices. Finally, a flowchart illustrates the possible way to realize some important milestones for the certain possible steps with significant contributions of MXenes

MXenes and the progress of Li-S battery development-a perspective

Lithium–sulfur (Li–S) battery has attracted tremendous interest owing to its high energy density at affordable costs. However, the irreversible active material loss and subsequent capacity fading caused by the uncontrollable shuttling of polysulfides have greatly hampered its commercial viability. MXenes, a novel class of 2D materials derived from nano-layered MAX phases, have been shown the potential to push the development of sulfur-based batteries to a next level owing to their high conductivity, strong polysulfide affinity and electrocatalytic properties. This perspective article focuses on the possible implications that MXene-based materials will have in the development of advanced sulfur-based batteries and their potential application in different upcoming technologies. In four sections possible developments are outlined which can be reached in the next 10 years, that enable a highly reliable, minimized Li–S battery finally combined with energy harvesters to fabricate autonomous power supplies for the next generation of microscaled devices like meteorological or geotechnical probes, wearable (medical) sensors or other suitable mobile devices. Finally, a flowchart illustrates the possible way to realize some important milestones for the certain possible steps with significant contributions of MXenes.Fil: Balach, Juan Manuel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Giebeler, Lars. Leibniz Institute for Solid State and Materials Research; Alemani

Stimuli-responsive nanogel composites and their application in nanomedicine

Nanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine

Stimuli-responsive nanogel composites and their application in nanomedicine

Nanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine

A top-down approach to build Li2S@rGO cathode composites for high-loading lithium–sulfur batteries in carbonate-based electrolyte

With a notable advantage in terms of specific capacity (1166 mAh g−1), lithium disulfide (Li2S) has been considered a promising cathode material for high-energy-density lithium–sulfur (Li–S) batteries. In contrast to pure sulfur, Li2S opens the opportunity to implement alternative anodes such as silicon or graphite instead of hardly controllable lithium metal. However, its intrinsically low conductivity and the formation of soluble lithium polysulfide species during cell operation resulting in a poor cycling stability, especially in carbonate-based electrolytes. Herein, a reduced graphene oxide-wrapped Li2S particles (Li2S@rGO) electrode is presented for improving the electrochemical performance of Li–S batteries in carbonate-based electrolytes. A hydrothermally prepared rGO-covered MoS2 particles composite was fully lithiated and irreversible decomposed at 0.01 V vs. Li/Li+ to in situ produce a Li2S@rGO composite with a high Li2S loading of ≈5 mg cm−2. Despite operating Li–S cells in a conventional carbonate-based electrolyte, the resulting cathode exhibits high initial capacity (975 mAh gLi2S −1 and 1401 mAh gS −1 at 0.1 C), low degradation rate (0.18% per cycle after 200 cycles at 2 C) and excellent Coulombic efficiency (≈99.5%). This work provides a simple strategy to fabricate practical high-loading Li2S cathodes for high-performance Li–S batteries “free” of polysulfide shuttle phenomenon.Fil: Zensich, Maximiliano Andres. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Jaumann, Tony. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Morales, Gustavo Marcelo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Giebeler, Lars. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Barbero, César Alfredo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Balach, Juan Manuel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentin

Lifetime vs. rate capability: Understanding the role of FEC and VC in high-energy Li-ion batteries with nano-silicon anodes

Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are the most frequently used electrolyte components to enhance the lifetime of anode materials in Li-ion batteries, but for silicon it is still ambiguous when FEC or VC is more beneficial. Herein, a nanostructured silicon/carbon anode derived from low-cost HSiCl3 is tailored by the rational choice of the electrolyte component, to obtain an anode material outperforming current complex silicon structures. We demonstrate highly reversible areal capacities of up to 5 mA h/cm2 at 4.4 mg/cm2 mass loading, a specific capacity of 1280 mA h/gElectrode, a capacity retention of 81% after 500 deep-discharge cycles versus lithium metal and successful full-cell tests with high-voltage cathodes meeting the requirements for real application. Electrochemical impedance spectroscopy and post-mortem investigation provide new insights in tailoring the interfacial properties of silicon-based anodes for high performance anode materials based on an alloying mechanism with large volume changes. The role of fluorine in the FEC-derived interfacial layer is discussed in comparison with the VC-derived layer and possible degradation mechanisms are proposed. We believe that this study gives a valuable understanding and provides new strategies on the facile use of additives for highly reversible silicon anodes in Li-ion batteries.Fil: Jaumann, Tony. Ifw Dresden; AlemaniaFil: Balach, Juan Manuel. Ifw Dresden; AlemaniaFil: Langklotz, Ulrike. Technische Universität Dresden; AlemaniaFil: Sauchuk, Viktar. Fraunhofer Institute for Ceramic Materials and Systems; AlemaniaFil: Fritsch, Marco. Fraunhofer Institute for Ceramic Materials and Systems; AlemaniaFil: Michaelis, Alexander. Technische Universität Dresden; AlemaniaFil: Teltevskij, Valerij. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Mikhailova, Daria. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Oswald, Steffen. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Klose, Markus. Leibniz Institute for Solid State and Materials Research; Alemania. Technische Universität Dresden; AlemaniaFil: Stephani, Guenter. Branch Lab Dresden. Fraunhofer Institute for Manufacturing Technology and Advanced Materials; ArgentinaFil: Hauser, Ralf. Branch Lab Dresden. Fraunhofer Institute for Manufacturing Technology and Advanced Materials; ArgentinaFil: Eckert, Jürgen. Technische Universität Dresden; Alemania. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Giebeler, Lars. Leibniz Institute for Solid State and Materials Research; Alemania. Technische Universität Dresden; Alemani

SEI-component formation on sub 5 nm sized silicon nanoparticles in Li-ion batteries: The role of electrode preparation, FEC addition and binders

Silicon is a promising negative electrode for secondary lithium-based batteries, but the electrochemical reversibility of particularly nanostructured silicon electrodes drastically depends on their interfacial characteristics, commonly known as the solid electrolyte interface (SEI). The beneficial origin of certain electrolyte additives or different binders is still discussed controversially owing to the challenging peculiarities of interfacial post-mortem investigations of electrodes. In this work, we address the common difficulties of SEI investigations of porous silicon/carbon nanostructures and study the addition of a fluoroethylene carbonate (FEC) as a stabilizing additive as well as the use of two different binders, carboxymethyl cellulose/styrene-butadiene rubber (CMC/SBR) and polyacrylic acid (PAA), for the SEI formation. The electrode is composed of silicon nanocrystallites below 5 nm diameter allowing a detailed investigation of interfacial characteristics of silicon owing to the high surface area. We first performed galvanostatic long-term cycling (400 times) and carried out comprehensive ex situ characterization of the cycled nanocrystalline silicon electrodes with XRD, EDXS, TEM and XPS. We modified the preparation of the electrode for post-mortem characterization to distinguish between electrolyte components and the actual SEI. The impact of the FEC additive and two different binders on the interfacial layer is studied and the occurrence of diverse compounds, in particular LiF, Li2O and phosphates, is discussed. These results help to understand general issues in SEI formation and to pave the way for the development of advanced electrolytes allowing for a long-term performance of nanostructured Si-based electrodes

Lifetime vs. rate capability: Understanding the role of FEC and VC in high-energy Li-ion batteries with nano-silicon anodes

Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are the most frequently used electrolyte components to enhance the lifetime of anode materials in Li-ion batteries, but for silicon it is still ambiguous when FEC or VC is more beneficial. Herein, a nanostructured silicon/carbon anode derived from low-cost HSiCl3 is tailored by the rational choice of the electrolyte component, to obtain an anode material outperforming current complex silicon structures. We demonstrate highly reversible areal capacities of up to 5 mA h/cm2 at 4.4 mg/cm2 mass loading, a specific capacity of 1280 mA h/gElectrode, a capacity retention of 81% after 500 deep-discharge cycles versus lithium metal and successful full-cell tests with high-voltage cathodes meeting the requirements for real application. Electrochemical impedance spectroscopy and post-mortem investigation provide new insights in tailoring the interfacial properties of silicon-based anodes for high performance anode materials based on an alloying mechanism with large volume changes. The role of fluorine in the FEC-derived interfacial layer is discussed in comparison with the VC-derived layer and possible degradation mechanisms are proposed. We believe that this study gives a valuable understanding and provides new strategies on the facile use of additives for highly reversible silicon anodes in Li-ion batteries

Carbon Nanomaterials: A versatile platform for energy technologies

Carbon nanomaterials play an important role in the development of alternative clean and sustainable energy technologies. These materials are a fascinating subject of study themselves, not only for its good chemical and mechanical stability, good electrical conductivity, high specific surface area and controlled pore size, but also because the pore structure can be further modified by active functional groups for the construction of more complex systems with a broad umbrella of applications. Furthermore, the surface chemistry, the morphology and the structural properties of the carbonaceous materials can be controlled by the judicious choice of the carbon precursor material and the route of fabrication. This minireview article spotlights the recent research progress on the synthesis of porous carbon nanomaterials and its application in energy storage and conversion. Particularly, we will discuss the synthesis and applications of mesoporous carbons as functional separator coatings in lithium-sulfur batteries, nanostructured carbons as catalyst supports for fuel cells and functionalized porous carbons as an acid catalyst for biofuel generation. Concluding the minireview, prospects for the future development of practical carbon nanomaterials are discussed.Fil: Zensich, Maximiliano Andres. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Baena Moncada, Angélica María. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Tamborini, Luciano Henri. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Coneo Rodríguez, Rusbel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Planes, Gabriel Angel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Morales, Gustavo Marcelo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Acevedo, Diego Fernando. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Balach, Juan Manuel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Bruno, Mariano Martín. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Barbero, César Alfredo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentin

Probing the interactions of phenol with oxygenated functional groups on curved fullerene-like sheets in activated carbon

The mechanism(s) of interactions of phenol with oxygenated functional groups (OH, COO and COOH) in nanopores of activated carbon (AC) is a contentious issue among researchers. This mechanism is of particular interest because a better understanding of the role of such groups in nanopores would essentially translate to advances in AC production and use, especially in regard to the treatment of organic-based wastewaters. We therefore attempt to shed more light on the subject by employing density functional theory (DFT) calculations in which fullerene-like models integrating convex or concave structure, which simulate the eclectic porous structures on AC surface, are adopted. TEM analysis, EDS mapping and Boehm titration are also conducted on actual phenol-adsorbed AC. Our results suggest the widely-reported phenomenon of decreased phenol uptake on AC due to increased concentration of oxygenated functional groups is possibly attributed to the increased presence of the latter on the convex side of the curved carbon sheets. Such a system effectively inhibits phenol from getting direct contact with the carbon sheet, thus constraining any available π–π interaction, while the effect of groups acting on the concave part of the curved sheet does not impart the same detriment