Li‐Driven Copper Extrusion/Re‐injection in Various Cu‐based Oxides and Sulfides

Abstract

The present paper is in part a continuation of our recent work dealing with the fully reversible Li‐driven Cu extrusion/injection of Cu in Cu2.33V4O11. The peculiar electrochemical property of such a compound was mainly ascribed to both structural considerations (presence of anchoring oxygen, giving flexibility to the [V4O11] layers) and electronic considerations, such as the existence of a delicate balance between the two Cu+/Cu2+ and V4+/V5+ redox centers. To support such suggestions, numerous compounds were revisited for their electrochemical–structural interplay. Network dimensionality, lattice flexibility, and cationic mobility parameters were addressed by exploring in depth the richness of the Cu–V–O system, while the importance of the donor/acceptor energy levels was checked via the choice of compounds having the right energy match between the two redox centers. As an extensive trial‐and‐error approach was not realistic, we relied on simple considerations based on the ionization energy of the various d‐metals to narrow down metal pairs having redox levels occurring within the same range of energies. Bearing this in mind, it was logical to consider compounds still containing Cu ions but with Nb instead of V or compounds having V and Ag instead of Cu. Regardless of our effort, it turned out that the number of potential candidates worth considering for practical applications is still very limited, in spite of the elegance of this new Li reactivity mechanism.

Controlling the Specific CO2Adsorption on Electrochemically Formed Metallic Copper Surfaces

“…2a) and that the molar CO 2 /Cu 0 ratio is very high for a surface effect, this mechanism could be plausible. However, the desorption occurring at high potential upon oxidation would in contrary indicate that the Cu(I)CO 2 34 further demonstrating that the copper redox is necessary for the gas desorption process.…”

Structural Evolution of Layered Manganese Oxysulfides during Reversible Electrochemical Lithium Insertion and Copper Extrusion

“…The differences between these two thiospinels have been ascribed to the higher mobility of Cu in CuTi2S4 than in CuCr2S4. 17 A systematic study on a few other Cu-V-O and Cu-V-S systems has revealed that the dimensionality and flexibility of the framework structure, together with the Cu mobility in the material, play important roles in governing the CDI reactions. 17 More recently, Li2Cu2O(SO4)2, has been investigated as a 4.7 V Li ion battery cathode.…”

“…17 A systematic study on a few other Cu-V-O and Cu-V-S systems has revealed that the dimensionality and flexibility of the framework structure, together with the Cu mobility in the material, play important roles in governing the CDI reactions. 17 More recently, Li2Cu2O(SO4)2, has been investigated as a 4.7 V Li ion battery cathode. Although such high voltage promotes electrolyte decomposition, the mechanistic study showed that Li2Cu2O(SO4)2 utilizes the Cu 2+/ Cu 3+ couple at 4.7 V, while the reaction pathway follows either Li (de)insertion or complex displacement-conversion pathways depending on the voltage window.…”

The composite structure of mixed τ-(Ag, Cu) V2O5 bronzes—Evidence for T dependant guest-species ordering and mobility

“…More recently, the combination of insertion and displacement processes operating reversibly was shown for Cu 7/3 V 4 O 11 opening the way to a new class of active material known as Combined Displacement Inser tion (CDI) electrodes [14]. Different studies allowed the definition of structural parameters responsible for the efficiency and rever sibility of displacement phenomena [15,16]. The delocalization of the displaceable species over several crystallographic sites, none of them being either disallowed or ideally suitable, appears as one of the most important.…”