Investigating intercalation mechanism of manganese oxide electrode in aqueous aluminum electrolyte

Optimization of Electrolytes for High-Performance Aqueous Aluminum-Ion Batteries

“…It was believed that this coinserted water crystal is critically important for the reversible intercalation of Al 3+ into the oxides by insulating the electrostatic interaction between the Al 3+ ion and the host MnO 2 . , A similar mechanism was suggested using other multivalent ions including Mg 2+ and Zn 2+ during the electrochemical cycling of manganese oxide electrode in aqueous electrolytes. , However, recent research has questioned whether Al 3+ intercalation into MnO 2 occurs at all and, instead, proposed that proton insertion is the dominant reaction mechanism. Wang et al studied the charge storage mechanism of α-MnO 2 in the Al­[OTF] 3 electrolyte using various electrochemical/spectroscopic characterizations and found that proton intercalation/deintercalation largely contributes to the reversible capacity of the cell, while only a small amount of Al 3+ could also intercalate into MnO 2 . It also proposed that a complex surface product containing Al 3+ , OH – , and [OTF] − was formed during cell discharge and this product dissolves during the charging process.…”

“…Wang et al studied the charge storage mechanism of α-MnO 2 in the Al[OTF] 3 electrolyte using various electrochemical/spectroscopic characterizations and found that proton intercalation/ deintercalation largely contributes to the reversible capacity of the cell, while only a small amount of Al 3+ could also intercalate into MnO 2 . 52 It also proposed that a complex surface product containing Al 3+ , OH − , and [OTF] − was formed during cell discharge and this product dissolves during the charging process. Alternatively, Balland et al used an in situ spectroelectrochemical methodology to determine the reaction mechanism of Al 3+ in the MnO 2 electrode using the Al[OTF] 3 electrolyte.…”

“…Given that the theoretical capacity of Al 0.07 MnO 2 is only 65 mAh g −1 , the dominant reaction mechanism occurring at the MnO 2 electrode when using Al[TFSI] 3 electrolyte is proton insertion donated from hydrated Al 3+ (eq 1) rather than Al 3+ insertion (eq 2), which is consistent with the recent work. 52,53 The MnO 2 positive electrode structural reversibility after the charge−discharge process was also examined using ex situ XRD. Figure 7A shows the XRD pattern of pristine MnO 2 , which was well indexed to the α-MnO 2 phase.…”

Effect of Ag Content on the Electrochemical Performance of Ag2Te Nanostructures Synthesized by Hydrothermal Route for Supercapacitor Applications

“…Figure shows a linear correlation between the scan rate and specific capacitance (f). As the sweeping rate rises, the C s regarding the fabricated electrode substance then decreased, and it might be due to less time of intercalation between the electrolyte ion and the electrode surface …”

“…As the sweeping rate rises, the C s regarding the fabricated electrode substance then decreased, and it might be due to less time of intercalation between the electrolyte ion and the electrode surface. 55 To further demonstrate the electrochemical efficiency of Ag 0.006 Te, Ag 0.012 Te, Ag 0.025 Te, Ag 0.05 Te, and Ag 0.1 Te electrodes, GCD analysis was then performed at different current densities from 1, 3, and 5 A g −1 in the potential window ranging from −0.05 to 0.65 V (Ag/AgCl), as depicted in Figure 4a−e. The GCD curves clearly display two potential plateaus, depicting the typical battery behavior.…”