[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.

Project "Extended DREAM: Multiple-length scale approach to functional nanomaterials”

Co-applicants:

- Kristina Edström, Uppsala University

- Werner Schweika, DREAM-ESS 

- Gunnar Svensson, MMK-SU 

- Peter Svedlindh and Erik Wetterskog, Uppsala University

Contact:

German Salazar-Alvarez

(german@mmk.su.se)

[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.

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.

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.