Université de Fribourg

A nano-rattle SnO2@carbon composite anode material for high-energy Li-ion batteries by melt diffusion impregnation

Maharajan, Sivarajakumar ; Kwon, Nam Hee ; Brodard, Pierre ; Fromm, Katharina M.

In: Nanomaterials, 2020, vol. 10, no. 4, p. 804

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO2@C nano- rattle composites based on < 10 nm SnO2 nanoparticles in and on porous amorphous carbon spheres were synthesized using a silica template and tin melting...

Université de Fribourg

Characteristics and properties of nano-LiCoO2 synthesized by pre-organized single source precursors: Li-ion diffusivity, electrochemistry and biological assessment

Brog, Jean?Pierre ; Crochet, Aurélien ; Seydoux, Joël ; Clift, Martin J. D. ; Baichette, Benoît ; Maharajan, Sivarajakumar ; Barosova, Hana ; Brodard, Pierre ; Spodaryk, Mariana ; Züttel, Andreas ; Rothen?Rutishauser, Barbara ; Kwon, Nam Hee ; Fromm, Katharina M.

In: Journal of Nanobiotechnology, 2017, vol. 15, p. 58

LiCoO₂ is one of the most used cathode materials in Li-ion batteries. Its conventional synthesis requires high temperature (>800 °C) and long heating time (>24 h) to obtain the micronscale rhombohedral layered high-temperature phase of LiCoO₂ (HT-LCO). Nanoscale HT-LCO is of interest to improve the battery performance as the lithium (Li⁺) ion pathway is expected to be shorter in...

Université de Fribourg

Distribution of silica-coated silver/gold nanostars in soft- and hardwood applying SERS-based imaging

Geers, Christoph ; Rodríguez-Lorenzo, Laura ; Placencia Peña, M. I. ; Brodard, Pierre ; Volkmer, T. ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Langmuir, 2016, vol. 32, no. 1, p. 274–283

Nanoparticles (NPs) in aqueous suspension have just begun to be exploited for the preservative treatment of wood. However, at present, there is very little information available on the distribution of NPs in wood after impregnation, due to associated analytical challenges. In this study, we present the detection of model NPs in softwood and hardwood by surface-enhanced Raman spectroscopy (SERS)....

Université de Fribourg

Impact of composite structure and morphology on electronic and ionic conductivity of carbon contained LiCoO2 cathode

Kwon, Nam Hee ; Yin, Hui ; Brodard, Pierre ; Sugnaux, Claudia ; Fromm, Katharina M.

In: Electrochimica Acta, 2014, vol. 134, p. 215–221

Cathodes in lithium ion batteries consist of an ionic conductor, an electronic conductor and a binder in order to make a composite that is both electronically and ionically conductive. The carbon coating on the cathode material plays a critical role for the electrochemical properties of lithium ion batteries due to the increased electronic conductivity. We explain the relationship between the...

Université de Fribourg

Kinetics of the chrysotile and brucite dehydroxylation reaction: a combined non-isothermal/isothermal thermogravimetric analysis and high-temperature X-ray powder diffraction study

Trittschack, Roy ; Grobéty, Bernard ; Brodard, Pierre

In: Physics and Chemistry of Minerals, 2014, vol. 41, no. 3, p. 197–214

The dehydroxylation reactions of chrysotile Mg₃Si₂O₅(OH)₄ and brucite Mg(OH)₂ were studied under inert nitrogen atmosphere using isothermal and non-isothermal approaches. The brucite decomposition was additionally studied under CO₂ in order to check the influence of a competing dehydroxylation/carbonation/decarbonisation reaction on the reaction kinetics. Isothermal experiments...