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Role of Cu current collector on electrochemical mechanism of Mg–S batteryAna Robba,
Maja Mežnar,
Alen Vižintin,
Jan Bitenc,
Jernej Bobnar,
Iztok Arčon,
Anna Randon-Vitanova,
Robert Dominko, 2020, original scientific article
Abstract: Development of magnesium sulfur battery is accompanied with all known difficulties present in Li–S batteries,
however with even more limited choice of electrolytes. In the present work, the influence of current collector on
electrochemical mechanism was investigated in light of different reports where improved behavior was ascribed
to electrolyte. Notable differences in cycling behavior are reported when Al current collector is replaced by Cu
current collector independent of electrolyte. The initial reduction of sulfur follows similar reaction path no mater
of current collector, but formation of MgS can be in competition with formation of CuS in the presence of Cu
cations. With the subsequent cycling cells prepared from cathodes deposited on Cu current collector show
decrease in the voltage and formation of single plateau during cycling. The change corresponds to the
involvement of Cu into the reaction and formation of redox couple Mg/CuS as determined by Cu K-edge XANES
measurements. Corrosion of Cu foil is identified by SEM and serves as a source of Cu cations for the chemical
reaction between Cu and polysulfides. Mg/CuS redox couple shows improved cycling stability, but theoretical
energy density is severely reduced due to substitution of S with CuS as cathode active material.
Keywords: Magnesium
Sulfur
Rechargeable batteries
Current collector
Copper
Corrosion
Published in RUNG: 16.01.2020; Views: 3573; Downloads: 0
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