Reduction of silver ions in molybdates: elucidation of framework acidity as the factor controlling charge balance mechanisms in aqueous zinc-ion electrolyte

Abstract

Across four molybdates, reduction of silver ions in aqueous zinc electrolyte is more facile with increasing acidity.

Manganese Molybdate Cathodes with Dual-Redox Centers for Aqueous Zinc-Ion Batteries: Impact of Electrolyte on Electrochemistry

“…36−39 Recently, Ag 2 MoO 4 and other variants of silver molybdate have been reported in weakly acidic zinc-based electrolytes with the focus on the formation of a conductive silver network. 40 Although both Ag + and Mo 6+ have been confirmed to be redox active and insight into possible mechanisms for initial cycles was reported, dis(charge) cyclability was not achieved in this work due to severe Mo dissolution. Manganese molybdenum oxide (MnMoO 4 ) has been implemented in Li-ion batteries as an anode material and is of interest as a bimetallic oxide with both metal centers being redox active which increases the theoretical capacity.…”

“…Additionally, molybdates, such as CoMoO 4 , and NiMoO 4 , have be employed as cathode materials in alkaline-based aqueous rechargeable zinc-ion batteries. − However, alkaline-based systems suffer from severe dendrite formation on the zinc metal anode. Additionally, the redox-active metal centers in these molybdate-based materials are either Co or Ni instead of Mo. − Recently, Ag 2 MoO 4 and other variants of silver molybdate have been reported in weakly acidic zinc-based electrolytes with the focus on the formation of a conductive silver network . Although both Ag + and Mo 6+ have been confirmed to be redox active and insight into possible mechanisms for initial cycles was reported, dis­(charge) cyclability was not achieved in this work due to severe Mo dissolution.…”

Mesoporous β-Ag2MoO4 nanopotatoes as supercapacitor electrodes

“…34 There are several feasible structures of A x MoO y in the Ag 2 O-MoO 3 phase diagram, including layered Ag 6 Mo 10 O 33 , Ag 2 Mo 2 O 7 with its two polymorphs, orthorhombic Ag 2 Mo 3 O 10 and spinel Ag 2 MoO 4 . 34 However, only a few of these Ag + containing A x MoO y have been examined, to the best of our knowledge, for their suitability and performance in supercapacitors. So far, a literature search only revealed a work that reported the coexistence of surface and intercalation redox reactions for layered-structured triclinic Ag 6 Mo 10 O 33 electrodes in energy storage.…”

“…In contrast, a-Ag 2 MoO 4 is mostly reported at high temperatures or with large amounts of surfactants. [32][33][34] However, the synthesis of a-Ag 2 MoO 4 generally required extreme conditions, such as high pressure and temperature, as well as high-tech equipment. When heated above the ambient temperature, the a-phase irreversibly changes into the b-phase.…”

“…Thus, A x MoO y materials containing Ag + rank high in research interest because Ag has excellent electrical conductivity, attributed to the materialized Ag + (reduced product) containing an anatomically distributed network of conductive Ag 0 particles that facilitate rapid electron transport. 34 There are several feasible structures of A x MoO y in the Ag 2 O–MoO 3 phase diagram, including layered Ag 6 Mo 10 O 33 , Ag 2 Mo 2 O 7 with its two polymorphs, orthorhombic Ag 2 Mo 3 O 10 and spinel Ag 2 MoO 4 . 34 However, only a few of these Ag + containing A x MoO y have been examined, to the best of our knowledge, for their suitability and performance in supercapacitors.…”