One of the major drawbacks in Lithium-air batteries is the sluggish kinetics of the oxygen reduction reaction (ORR). In this context, better performances can be achieved by adopting a suitable electrocatalyst, such as MnO2. Herein, we tried to design nano-MnO2 tuning the final ORR electroactivity by tailoring the doping agent (Co or Fe) and its content (2% or 5% molar ratios). Staircase-linear sweep voltammetries (S-LSV) were performed to investigate the nanopowders electrocatalytic behavior in organic solvent (propylene carbonate, PC and 0.15 M LiNO3 as electrolyte). Two percent Co-doped MnO2 revealed to be the best-performing sample in terms of ORR onset shift (of ~130 mV with respect to bare glassy carbon electrode), due to its great lattice defectivity and presence of the highly electroactive γ polymorph (by X-ray diffraction analyses, XRPD and infrared spectroscopy, FTIR). 5% Co together with 2% Fe could also be promising, since they exhibited fewer diffusive limitations, mainly due to their peculiar pore distribution (by Brunauer-Emmett-Teller, BET) that disfavored the cathode clogging. Particularly, a too-high Fe content led to iron segregation (by energy dispersive X-ray spectroscopy, EDX, X-ray photoelectron spectroscopy, XPS and FTIR) provoking a decrease of the electroactive sites, with negative consequences for the ORR.
ORR in Non-Aqueous Solvent for Li-Air Batteries : The Influence of Doped MnO2-Nanoelectrocatalyst / E. Pargoletti, A. Salvi, A. Giordana, G. Cerrato, M. Longhi, A. Minguzzi, G. Cappelletti, A. Vertova. - In: NANOMATERIALS. - ISSN 2079-4991. - 10:9(2020 Sep 01), pp. 1735.1-1735.15.
|Titolo:||ORR in Non-Aqueous Solvent for Li-Air Batteries : The Influence of Doped MnO2-Nanoelectrocatalyst|
PARGOLETTI, ELEONORA (Primo)
CAPPELLETTI, GIUSEPPE (Penultimo) (Corresponding)
VERTOVA, ALBERTO (Ultimo) (Corresponding)
|Parole Chiave:||Li-air battery; cobalt doping; electrocatalyst; iron doping; manganese dioxide nanoparticles; organic solvent; oxygen reduction reaction|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Data di pubblicazione:||1-set-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.3390/nano10091735|
|Appare nelle tipologie:||01 - Articolo su periodico|