Sajjad Ahangar Zonouzi, Rahmatollah Khodabandeh, Habibollah Safarzadeh, HabibAminfar, Yuliya Trushkina, Mousa Mohammadpourfard, Morteza Ghanbarpour, German Salazar-Alvarez
Experimental Thermal and Fluid Science (2017) In press
DOI: 10.1016/j.expthermflusci.2017.10.013
Abstract:
In this paper, the effects of applying magnetic field on hydrodynamics and heat transfer of Fe3O4/water magnetic nanofluid flowing inside a vertical tube have been studied experimentally. The applied magnetic field was resulted from quadrupole magnets located at different axial positions along the tube length. The variations of the local heat transfer coefficient and also the pressure drop of the ferrofluid flow along the length of the tube by applying the magnetic quadrupole field have been investigated for different Reynolds numbers. The obtained experimental results show maximum enhancements of 23.4%, 37.9% and 48.9% in the local heat transfer coefficient for the magnetic nanofluid with 2 vol.% Fe3O4 in the presence of the quadrupole magnets located at three different axial installation positions for the Reynold number of 580 and the relative increase in total pressure drop by applying the magnetic field is about 1% for Re=580. The increase of the heat transfer coefficient is due to the radial magnetic force toward the heated wall generated by magnetic quadrupole field acting over the ferrofluid flowing inside the tube so that the velocity of the ferrofluid in the vicinity of the heated wall is increased. It is also observed that the enhancement of heat transfer coefficient by applying magnetic quadrupole is decreased with increasing the Reynolds number.
2017-11-02
2017-10-13
[MRS Symposium] SM07 - Functional (Bio)polymers in Energy and Environment Applications
Time and time again, "multidisciplinary" research is touted as essential to innovation. That is why, from April 2-6, 2018, researchers working in seemingly unrelated fields will gather in Phoenix, Arizona, to promote, share and discuss issues and developments across disciplines.
The 2018 MRS Spring Meeting & Exhibit is the key forum to present research to an interdisciplinary and international audience. It provides a window on the future of materials science, and offers an opportunity for researchers—from students and postdoctoral fellows, to Nobel and Kavli Prize Laureates—to exchange technical information and network with colleagues.
The 2018 MRS Spring Meeting & Exhibit is the key forum to present research to an interdisciplinary and international audience. It provides a window on the future of materials science, and offers an opportunity for researchers—from students and postdoctoral fellows, to Nobel and Kavli Prize Laureates—to exchange technical information and network with colleagues.
Call for Papers
Abstract submission deadline is October 31, 2017.
Symposium SM07—Functional (Bio)polymers in Energy and Environment Applications
The development of inexpensive, benign and efficient sustainable materials, which can replace our dependence on the fossil reserves, is imperative. This approach can take many forms, either by improving the lifetime of a material, making it lighter, easier and more economical to transport, or by creating novel materials that allow for new functions. In this context, the exploitation of functional materials based on renewable and sustainable (bio)polymers and bioplastics (i.e., biological polymers and bio-derived synthetic polymers) such as poly(ionic liquid)s (PILs), polysaccharides, fibrous proteins, etc represents an approach that can satisfy these stringent requirements.
Improved chemical and characterization methods have promoted the growing interest in (biopolymers as it enabled tuning their surface properties and the observation of their intricate nanostructures. Functional biopolymers and bioplastics have found their way in applications in catalysis, sensing, energy storage and energy generation. However, the understanding of the coupling of the micro-, meso-, and macroscopic-length scales is far from being understood, particularly in combination with inorganic nanomaterials. This symposium will cover the range of applications of biopolymers and bioplastics in energy and environment applications.
The topics of the symposium include interdisciplinary areas merging chemistry, biology, polymer science and materials science. The invited abstracts will provide the required bridges to connect these areas with an emphasis on their characterization methods and applications. These, in turn, will help to initiate discussions towards the implementation of the various functional (bio)polymers in different areas and the cross-fertilization of the characterization methods that are used.
Improved chemical and characterization methods have promoted the growing interest in (biopolymers as it enabled tuning their surface properties and the observation of their intricate nanostructures. Functional biopolymers and bioplastics have found their way in applications in catalysis, sensing, energy storage and energy generation. However, the understanding of the coupling of the micro-, meso-, and macroscopic-length scales is far from being understood, particularly in combination with inorganic nanomaterials. This symposium will cover the range of applications of biopolymers and bioplastics in energy and environment applications.
The topics of the symposium include interdisciplinary areas merging chemistry, biology, polymer science and materials science. The invited abstracts will provide the required bridges to connect these areas with an emphasis on their characterization methods and applications. These, in turn, will help to initiate discussions towards the implementation of the various functional (bio)polymers in different areas and the cross-fertilization of the characterization methods that are used.
2017-10-09
Effects of Different Manufacturing Processes on TEMPO-oxidized CNF Performance as binder for Flexible Lithium-ion Batteries
Huiran Lu, Valentina Guccini, Hyeyun Kim, German Salazar-Alvarez, Göran Lindbergh, and Ann Cornell*
ACS Appl. Mater. Interfaces (2017)
DOI: 10.1021/acsami.7b10307
Abstract:
Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF, such as charge density and degree of homogenization, affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and various degrees of homogenization and their performance as binder for flexible LiFePO4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with the CNF with low charge density, as observed with atomic force microscope (AFM). Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed with rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (1550 µmol g-1) and lowest degree of homogenization (3+3 passes in the homogenizer) achieved the overall best performance, including a high Young’s modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g-1 even up to 1C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results can also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.
ACS Appl. Mater. Interfaces (2017)
DOI: 10.1021/acsami.7b10307
Abstract:
Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF, such as charge density and degree of homogenization, affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and various degrees of homogenization and their performance as binder for flexible LiFePO4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with the CNF with low charge density, as observed with atomic force microscope (AFM). Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed with rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (1550 µmol g-1) and lowest degree of homogenization (3+3 passes in the homogenizer) achieved the overall best performance, including a high Young’s modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g-1 even up to 1C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results can also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.
2017-07-18
[OPEN ACCESS] Superlattice growth and rearrangement during evaporation-induced nanoparticle self-assembly
Elisabeth Josten*, Erik Wetterskog, Artur Glavic, Peter Boesecke, Artem Feoktystov, Elke Brauweiler-Reuters, Ulrich Rücker, German Salazar-Alvarez, Thomas Brückel & Lennart Bergström
Scientific Reports 7 (2017) 2802
DOI: 10.1038/s41598-017-02121-4
Abstract:
Understanding the assembly of nanoparticles into superlattices with well-defined morphology and structure is technologically important but challenging as it requires novel combinations of in-situ methods with suitable spatial and temporal resolution. In this study, we have followed evaporation-induced assembly during drop casting of superparamagnetic, oleate-capped γ-Fe2O3 nanospheres dispersed in toluene in real time with Grazing Incidence Small Angle X-ray Scattering (GISAXS) in combination with droplet height measurements and direct observation of the dispersion. The scattering data was evaluated with a novel method that yielded time-dependent information of the relative ratio of ordered (coherent) and disordered particles (incoherent scattering intensities), superlattice tilt angles, lattice constants, and lattice constant distributions. We find that the onset of superlattice growth in the drying drop is associated with the movement of a drying front across the surface of the droplet. We couple the rapid formation of large, highly ordered superlattices to the capillary-induced fluid flow. Further evaporation of interstitital solvent results in a slow contraction of the superlattice. The distribution of lattice parameters and tilt angles was significantly larger for superlattices prepared by fast evaporation compared to slow evaporation of the solvent.
Scientific Reports 7 (2017) 2802
DOI: 10.1038/s41598-017-02121-4
Abstract:
Understanding the assembly of nanoparticles into superlattices with well-defined morphology and structure is technologically important but challenging as it requires novel combinations of in-situ methods with suitable spatial and temporal resolution. In this study, we have followed evaporation-induced assembly during drop casting of superparamagnetic, oleate-capped γ-Fe2O3 nanospheres dispersed in toluene in real time with Grazing Incidence Small Angle X-ray Scattering (GISAXS) in combination with droplet height measurements and direct observation of the dispersion. The scattering data was evaluated with a novel method that yielded time-dependent information of the relative ratio of ordered (coherent) and disordered particles (incoherent scattering intensities), superlattice tilt angles, lattice constants, and lattice constant distributions. We find that the onset of superlattice growth in the drying drop is associated with the movement of a drying front across the surface of the droplet. We couple the rapid formation of large, highly ordered superlattices to the capillary-induced fluid flow. Further evaporation of interstitital solvent results in a slow contraction of the superlattice. The distribution of lattice parameters and tilt angles was significantly larger for superlattices prepared by fast evaporation compared to slow evaporation of the solvent.
2017-04-07
[OPEN POSITION]: PhD-position in solid state physics – X-ray and Neutron scattering
PhD-position in solid state physics – X-ray and Neutron scattering
Published: 2017-04-04
Uppsala University is an international research university focused on the development of science and education. Our most important assets are all the individuals who with their curiosity and their dedication make Uppsala University one of Sweden’s most exciting work places. Uppsala University has 40,000 students, 7,000 employees and a turnover of SEK 6,5 billion.
A PhD-position in solid state physics – X-ray and Neutron scattering in the subject Engineering Science with specialization in the solid state physics, at the Ångström Laboratory, Department of Engineering Sciences, Division of Solid state physics (http://teknik.uu.se/solid-state-physics+/?languageId=3). Starting date as soon as possible.
This project will be conducted as part of a collaborative effort between Structural Chemistry and Solid State Physics, both situated at the Ångström Laboratory. The Ångström Advanced Battery Centre at Structural chemistry is the largest battery research group in the Nordic countries. Our research focuses on all aspects of the chemistry of rechargeable batteries; recently, we are looking at advanced nanomaterials with the aim of making energy storage more sustainable and cost-effective. The Magnetism group at the division of Solid State Physics is working with experimental research on novel magnetic materials, and has made key contributions to this research field. Apart from pursuing basic research on magnetic materials, the group is also involved in interdisciplinary research; developing magnetic nanoparticle based bioassays, and the study of the magnetization dynamics of self-assembled nanoparticle assemblies.
The PhD project will focus on the characterization of nanomaterials using neutron and X-ray scattering. The focal point of the project is the combination of scattering techniques at multiple length scales, in order gain insights in materials and processes by covering both the atomic- and the mesoscale. Several different materials will be explored throughout the project, including self-assembled magnetic nanomaterials and battery components. This work is funded by the Swedish research council, with the aim to develop several sample environments for the neutron diffractometer DREAM at the European spallation source (ESS). The work is performed in close collaboration with Stockholm University and involves travel to major facilities in EU and other parts of the world. We offer a varied and exciting work, with well-established collaboration with the department of Chemistry at the Ångström laboratory as well as with nationally and internationally renowned research groups.
We are seeking candidates with a MSc in engineering or science. A strong motivation and ability to work independently is desirable, and good verbal and written skills in English are required. Experience in materials science work will be considered as a merit.
The PhD position is for four years, extendable to a maximum of five years including departmental duties at a level of at most 20% (typically teaching).
Further information http://www.teknat.uu.se and http://www.teknik.uu.se.
Local guidelines for salary placement are used.
Uppsala University aims for gender balance and diversity in all activities in order to achieve a higher quality at all levels of the organization. We therefore welcome applicants of any gender and with different birth background, functionality and life experience.
Applications should include a brief description of research interests and relevant experience, a CV, copies of diplomas and certificates, thesis (or a draft thereof) and other relevant documents. The candidates are encouraged to provide letter(s) of recommendation and contact information to reference persons.
For further information please contact Dr Erik Wetterskog, +46-(0)18-471 3115, erik.wetterskog@angstrom.uu.se
You are welcome to submit your application no later than 25 April 2017, UFV-PA 2017/1102.
We decline offers of recruitment and advertising help. We only accept the application the way described in the advertisement.
Placement: Department of Engineering Sciences
Type of employment: Full time , Temporary position longer than 6 months
Pay: Fixed pay
Number of positions: 1
Working hours: 100 %
Town: Uppsala
County: Uppsala län
Country: Sweden
Union representative: Ellena Papaioannou, Seko 018-471 3315
Marie Ols, TCO/ST 018-471 2459
Per Sundman, Saco-rådet 018-471 1485
Marie Ols, TCO/ST 018-471 2459
Per Sundman, Saco-rådet 018-471 1485
Number of reference: UFV-PA 2017/1202
Last application date: 2017-04-25
[OPEN POSITION] Postdoctoral Fellow in Materials Chemistry - Neutron Scattering
Postdoctoral Fellow in Materials Chemistry - Neutron ScatteringRef. No. SU FV-0992-17
at the Department of Materials and Environmental Chemistry. Closing date: 30 April 2017.
The Department of Materials and Environmental Chemistry at Stockholm University is one of the largest with about 150 persons working with the synthesis and structural characterisation of materials.
Project description
We are looking for a postdoc who can carry out research with neutron diffraction and SANS of nanomaterials with technical applications as biomaterials, battery components and potentially magnetic materials.
We are looking for a postdoc who can carry out research with neutron diffraction and SANS of nanomaterials with technical applications as biomaterials, battery components and potentially magnetic materials.
The project is a collaboration between Stockholm University, Uppsala University and the European Spallation Source (ESS) and has as a long-term plan to expand the neutron diffractometer DREAM at the ESS in Lund to study nanomaterials. Within the project, we will design different sample environments to enable the simultaneous acquisition of data in two length scales (atomic and nanoscopic). This will be used to study three different materials classes that have a strong research tradition in Sweden: biomaterials, batteries, and magnetic materials. In this way, the connection between the variations in the crystal structure and nanoparticle morphology can be established. Some examples of the possible studies include the self-assembly of small cellulose fibres, how the structure of batteries changes during usage, or how magnetic nanoparticles assemble under an applied magnetic field. The project is financed by the Swedish Research Council.
Main responsibilities
The postdoctoral fellow will work together with a team that will focus in studying different types of nanomaterials with neutron scattering at the atomic (diffraction) and nanoscopic (small angle neutron scattering, SANS) levels. The work implies comprehensive experiments with neutron scattering in neutron facilities around the world with the focus on the multiple length scale approach. The work also includes the design, development, and testing of different sample environments for the in-situ characterisation of two different types of nanomaterials such as nanocellulose and iron oxide nanoparticles.
The postdoctoral fellow will work together with a team that will focus in studying different types of nanomaterials with neutron scattering at the atomic (diffraction) and nanoscopic (small angle neutron scattering, SANS) levels. The work implies comprehensive experiments with neutron scattering in neutron facilities around the world with the focus on the multiple length scale approach. The work also includes the design, development, and testing of different sample environments for the in-situ characterisation of two different types of nanomaterials such as nanocellulose and iron oxide nanoparticles.
Qualification requirements
Postdoctoral positions are appointed primarily for purposes of research. Applicants are expected to hold a Swedish doctoral degree or an equivalent degree from another country. The applicant should have a doctoral degree in chemistry or physics with a strong focus on condensed matter or similar qualifications.
Postdoctoral positions are appointed primarily for purposes of research. Applicants are expected to hold a Swedish doctoral degree or an equivalent degree from another country. The applicant should have a doctoral degree in chemistry or physics with a strong focus on condensed matter or similar qualifications.
Assessment criteriaThe degree should have been completed no more than three years before the deadline for applications. An older degree may be acceptable under special circumstances, such as sick leave, parental leave, clinical attachment, elected positions in trade unions, or similar.
In the appointment process special attention will be given to research skills. Documented experience of neutron scattering is required. Experience in X-ray scattering in general and total scattering in particular is advantageous.
Terms of employment
The position involves full-time employment for a maximum of two years, with the possibility of extension under special circumstances.
The position involves full-time employment for a maximum of two years, with the possibility of extension under special circumstances.
Stockholm University strives to be a workplace free from discrimination and with equal opportunities for all.
Contact
Further information about the position can be obtained from the PI, Assoc. Prof. German Salazar-Alvarez, telephone: +46 8 16 39 42, german@mmk.su.se, or Head of Department, Prof. Gunnar Svenson, telephone: +46 8 16 12 54, gunnar@mmk.su.se.
Further information about the position can be obtained from the PI, Assoc. Prof. German Salazar-Alvarez, telephone: +46 8 16 39 42, german@mmk.su.se, or Head of Department, Prof. Gunnar Svenson, telephone: +46 8 16 12 54, gunnar@mmk.su.se.
Union representatives
Anqi Lindblom-Ahlm (Saco-S) and Lisbeth Häggberg (Fackförbundet ST and Lärarförbundet), telephone: +46 8 16 20 00 (operator), and seko@seko.su.se (SEKO).
Anqi Lindblom-Ahlm (Saco-S) and Lisbeth Häggberg (Fackförbundet ST and Lärarförbundet), telephone: +46 8 16 20 00 (operator), and seko@seko.su.se (SEKO).
Application
Apply for the position at Stockholm University's recruitment system by clicking the "Apply" button. It is the responsibility of the applicant to ensure that the application is complete in accordance with the instructions in the job advertisement, and that it is submitted before the deadline.
Apply for the position at Stockholm University's recruitment system by clicking the "Apply" button. It is the responsibility of the applicant to ensure that the application is complete in accordance with the instructions in the job advertisement, and that it is submitted before the deadline.
Please include the following information with your application
- Your contact details and personal data
- Your highest degree
- Your language skills
- Contact details for 2–3 references
and, in addition, please include the following documents
- Cover letter
- CV – degrees and other completed courses, work experience and a list of publications
- Research proposal (no more than 3 pages) describing:
– why you are interested in the field/project described in the advertisement
– why and how you wish to complete the project
– what makes you suitable for the project in question - Copy of PhD diploma
- Letters of recommendation (no more than 3 files)
- Publications in support of your application (no more than 3 files).
The instructions for applicants are available at: Instructions – Applicants.
Stockholm University – our education and research produce results.
URL to the original announcement pagehttp://www.su.se/english/about/vacancies/vacancies-new-list?rmpage=job&rmjob=3120&rmlang=UK
2017-03-23
[Project Grant] Extended DREAM: Multiple-length scale approach to functional nanomaterials
A team led by German Salazar-Alvarez, researcher at the Department of Materials and Environmental Chemistry, Stockholm University, has been awarded 10 MSEK by the Swedish Research Council, VR, to develop sample environments that will allow the in-situ and in-operando multiscale characterization of novel functional nanomaterials such as biomaterials, battery components, and magnetic nanoparticles. Coupled to the high brilliance of the ESS source the project will provide exceptional opportunities for the envisioned materials. Also, testing of the new sample environments at existing neutron facilities will promote the training of the Swedish community in neutron scattering.
Co-applicants:
- Peter Svedlindh and Erik Wetterskog, Uppsala University
Contact:
(german@mmk.su.se)
2017-03-16
[OPEN ACCESS] A CaCO3/nanocellulose-based bioinspired nacre-like material
Masoud Farhadi-Khouzani, Christina Schütz, Grażyna M. Durak, Jordina Fornell, Jordi Sort, Germán Salazar-Alvarez, Lennart Bergström and Denis Gebauer*
J. Mater. Chem. A, (2017)
DOI:10.1039/C6TA09524K
Abstract:
Nacre continues to be an inspiration for the fabrication of strong and tough materials from renewable and earth-abundant raw materials. Herein, we showed how a nacre-like hybrid material based on nanocellulose (NC) and CaCO3 can be prepared via the sequential infiltration of polymer-stabilised CaCO3 liquid precursors into layers of pre-deposited NC films. Layer-by-layer assembly of the NC films followed by controlled spreading and infiltration with liquid CaCO3 precursors generated a lamellar material with an architecture and iridescent appearance similar to those of nacre. The wettability of the NC films towards the liquid CaCO3 precursors was controlled by hydroxyl and carboxyl functionalization of the NC fibrils and the addition of magnesium ions. The combination of a high stiffness and plasticity of the nacre-like NC/CaCO3 hybrid materials show that excellent mechanical properties can be obtained employing a fibrillar organic constituent that is relatively hard. The fabrication of a nacre-like hybrid material via an aqueous route of assembly and infiltration processing demonstrates how a sustainable composite material with outstanding properties can be produced using the most abundant biopolymer and biomineral on earth.
J. Mater. Chem. A, (2017)
DOI:10.1039/C6TA09524K
Abstract:
Nacre continues to be an inspiration for the fabrication of strong and tough materials from renewable and earth-abundant raw materials. Herein, we showed how a nacre-like hybrid material based on nanocellulose (NC) and CaCO3 can be prepared via the sequential infiltration of polymer-stabilised CaCO3 liquid precursors into layers of pre-deposited NC films. Layer-by-layer assembly of the NC films followed by controlled spreading and infiltration with liquid CaCO3 precursors generated a lamellar material with an architecture and iridescent appearance similar to those of nacre. The wettability of the NC films towards the liquid CaCO3 precursors was controlled by hydroxyl and carboxyl functionalization of the NC fibrils and the addition of magnesium ions. The combination of a high stiffness and plasticity of the nacre-like NC/CaCO3 hybrid materials show that excellent mechanical properties can be obtained employing a fibrillar organic constituent that is relatively hard. The fabrication of a nacre-like hybrid material via an aqueous route of assembly and infiltration processing demonstrates how a sustainable composite material with outstanding properties can be produced using the most abundant biopolymer and biomineral on earth.
Extensively interconnected silicon nanoparticles via carbon network derived from ultrathin cellulose nanofibers as high performance lithium ion battery anodes
Jong Min Kim, Valentina Guccini, Kwang-dong Seong, Jiseop Oh, German Salazar-Alvarez*, Yuanzhe Piao*.
Carbon 118 (2017) 8–17
DOI: 10.1016/j.carbon.2017.03.028
Abstract:
Silicon is a good alternative to conventional graphite anode but it has bad cycling and rate performance. To overcome these severe problems, extensively interconnected silicon nanoparticles using carbon network derived from ultrathin cellulose nanofibers were synthesized. Ultrathin cellulose nanofibers, an abundant and sustainable material, entangle each silicon nanoparticle and become extensively interconnected carbon network after pyrolysis. This wide range interconnection provides an efficient electron path by decreasing the likelihood that electrons experience contact resistivity and also suppresses the volume expansion of silicon during lithiation. In addition, Ultrathin cellulose nanofibers are carboxylated and therefore adhesive to silicon nanoparticles through hydrogen bonding. This property makes ultrathin cellulose the perfect carbon source when making silicon composites. As a consequence, it exhibits 808 mAh g−1 of the reversible capacity after 500 cycles at high current density of 2 A g−1 with a coulombic efficiency of 99.8%. Even at high current density of 8 A g−1, it shows a high reversible discharge capacity of 464 mAh g−1. Moreover, extensively interconnected carbon network prevents the formation of a brittle electrode with a water-based binder. Therefore, this remarkable material has a huge potential for LIBs applications.
Carbon 118 (2017) 8–17
DOI: 10.1016/j.carbon.2017.03.028
Abstract:
Silicon is a good alternative to conventional graphite anode but it has bad cycling and rate performance. To overcome these severe problems, extensively interconnected silicon nanoparticles using carbon network derived from ultrathin cellulose nanofibers were synthesized. Ultrathin cellulose nanofibers, an abundant and sustainable material, entangle each silicon nanoparticle and become extensively interconnected carbon network after pyrolysis. This wide range interconnection provides an efficient electron path by decreasing the likelihood that electrons experience contact resistivity and also suppresses the volume expansion of silicon during lithiation. In addition, Ultrathin cellulose nanofibers are carboxylated and therefore adhesive to silicon nanoparticles through hydrogen bonding. This property makes ultrathin cellulose the perfect carbon source when making silicon composites. As a consequence, it exhibits 808 mAh g−1 of the reversible capacity after 500 cycles at high current density of 2 A g−1 with a coulombic efficiency of 99.8%. Even at high current density of 8 A g−1, it shows a high reversible discharge capacity of 464 mAh g−1. Moreover, extensively interconnected carbon network prevents the formation of a brittle electrode with a water-based binder. Therefore, this remarkable material has a huge potential for LIBs applications.
2017-03-11
High-performance magnetic activated carbon from solid waste from lignin conversion processes. Part I: Their use as adsorbents for CO2
Wenming Hao, Fredrik Björnerbäck, Yulia Trushkina, Mikel Oregui-Bengoechea, German Salazar-Alvarez, Tanja Barth, and Niklas Hedin
ACS Sustainable Chem. Eng., (2017)
DOI: 10.1021/acssuschemeng.6b02795
Abstract:
Lignin is naturally abundant and a renewable precursor with a potential to be used in the production of both chemicals and materials. As many lignin conversion processes suffer from a significant production of solid wastes in the form of hydrochars, this study focused on transforming hydrochars into magnetic activated carbons (MAC). The hydrochars were produced via hydrothermal treatment of lignins together with formic acid. The activation of the hydrochars was performed chemically with KOH with a focus on the optimization of the MACs as adsorbents for CO2. MACs are potentially relevant to carbon capture and storage (CCS) and gas purification processes. In general, the MACs had high specific surface areas (up to 2875 m2/g), high specific pore volumes, and CO2 adsorption capacities of up to 6.0 mmol/g (1 atm, 0 °C). The textual properties of the MACs depended on the temperature of the activation. MACs activated at a temperature of 700 °C had very high ultramicropore volumes, which are relevant for potential adsorption-driven separation of CO2 from N2. Activation at 800 °C led to MACs with larger pores and very high specific surface areas. This temperature-dependent optimization option, combined with the magnetic properties, provided numerous potential applications of the MACs besides of CCS. The hydrochar derived from eucalyptus lignin, and the corresponding MACs displayed soft magnetic behavior with coercivities of < 100 Oe and saturation magnetization values of 1-10 emu/g.
ACS Sustainable Chem. Eng., (2017)
DOI: 10.1021/acssuschemeng.6b02795
Abstract:
Lignin is naturally abundant and a renewable precursor with a potential to be used in the production of both chemicals and materials. As many lignin conversion processes suffer from a significant production of solid wastes in the form of hydrochars, this study focused on transforming hydrochars into magnetic activated carbons (MAC). The hydrochars were produced via hydrothermal treatment of lignins together with formic acid. The activation of the hydrochars was performed chemically with KOH with a focus on the optimization of the MACs as adsorbents for CO2. MACs are potentially relevant to carbon capture and storage (CCS) and gas purification processes. In general, the MACs had high specific surface areas (up to 2875 m2/g), high specific pore volumes, and CO2 adsorption capacities of up to 6.0 mmol/g (1 atm, 0 °C). The textual properties of the MACs depended on the temperature of the activation. MACs activated at a temperature of 700 °C had very high ultramicropore volumes, which are relevant for potential adsorption-driven separation of CO2 from N2. Activation at 800 °C led to MACs with larger pores and very high specific surface areas. This temperature-dependent optimization option, combined with the magnetic properties, provided numerous potential applications of the MACs besides of CCS. The hydrochar derived from eucalyptus lignin, and the corresponding MACs displayed soft magnetic behavior with coercivities of < 100 Oe and saturation magnetization values of 1-10 emu/g.
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