Spectroscopic insights into the electrochemical mechanism of rechargeable calcium/sulfur batteries
Calcium batteries represent a promising alternative to lithium metal systems. The combination of the low redox potential and low cost and the energy-dense calcium anode (2073 mAh/cm3, similar to 2044 mAh/cm3 for Li) with appropriate low-cost cathode materials such as sulfur could produce a game-changing technology in several fields of applications. In this work, we present the reversible activity of a proof-of-concept Ca/S battery at room temperature, characterized by a surprising medium-term cycling stability with low polarization, promoted by the use of a simple positive electrode made of sulfur supported on an activated carbon cloth scaffold, and a state-of-the-art fluorinated alkoxyborate-based electrolyte. Insights into the electrochemical mechanism governing the chemistry of the Ca/S system were obtained for the first time by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The mechanism implies the formation of different types of soluble polysulfide species during both charge and discharge at room temperature, and the formation of solid CaS at the end of discharge. The reversible electrochemical activity is proven by the reformation of elemental sulfur at the end of the following charge. These promising results open the way to the comprehension of emerging Ca/S systems, which may represent a valid alternative to Mg/S and Li/S batteries.
13
2020-10-17 01:53:08
1033
elektrokemija, baterije, spektroskopija, žveplo
r6
Antonio
Scafuri
70
Romain
Berthelot
70
Klemen
Pirnat
70
Alen
Vižintin
70
Jan
Bitenc
70
Giuliana
Aquilanti
70
Dominique
Foix
70
Rémi
Dedryvère
70
Iztok
Arčon
70
Robert
Dominko
70
Lorenzo
Stievano
70
COBISS_ID
3
32411907
ISSN pri članku
9
0897-4756
OceCobissID
13
6557189
DOI
15
10.1021/acs.chemmater.0c02074
NUK URN
18
URN:SI:UNG:REP:3DHK8QHO
Ce-S-bat_Lorenzo_2020_reprint_acs.chemmater.0c02074.pdf
3925980
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