The Mechanism of the Interfacial Charge and Mass Transfer during Intercalation of Alkali Metal Cations

Abstract

Intercalation of alkali metal cations, like Li+ or Na+, follows the same three‐stage mechanism of the interfacial charge and mass transfer irrespective of the nature of the electrolyte, electrolyte composition or electrode material.

Dynamic Impedance Spectroscopy of Nickel Hexacyanoferrate Thin Films

“…This is at variance with some literature, in which by using static impedance a three step mechanism was proposed. [47] We attributed the observed differences between literature and our results to instability of the thin film and/or distortions due to the cell geometry or reference electrode. The kinetic parameters for both cations (Na + and K + ) were observed to be in the same order of magnitude indicating similar rates of the kinetic processes which was attributed to similarity in ionic and hydrated radii of the inserted cations.…”

“…In addition to this, we want to stress that the spectra obtained in this work were in contrast with what has been reported by Ventosa et al for NiHCF and Prussian blue thin films, [47] where the impedance spectra obtained in NiHCF thin film in aqueous and non-aqueous solutions of univalent cations in the frequency range of 50 kHz to 100 mHz exhibited an inductive loop in low frequency region. As discussed in the introduction, the origin of this loop could be caused by the instability of the thin films or by artefacts arising from the electrochemical setup.…”

“…This could be one of the reason for the peculiar shape of the impedance spectra reported by Ventosa et al who have shown for similar films impedance spectra with inductive loop in the low frequency region. [47] Other possible reason for the inductive loops in the low frequency region could be artefacts from the cell set-up and the reference electrode. It has been reported that if the impedance of the reference electrode is around 10 kΩ, its coupling with the inherent stray capacitance of the potentiostat may generate distortions in the range of kHz.…”

High‐Efficiency Na‐Storage Performance of a Nickel‐Based Ferricyanide Cathode in High‐Concentration Electrolytes for Aqueous Sodium‐Ion Batteries

“…[25][26][27] Among those materials, nickel-based ferricyanides (A x Ni y [Fe(CN 6 )]·zH 2 O, A = K or Na, NiHCF) exhibit promising application for low-cost aqueous SIBs owing to their open structural framework and reversible intercalation chemistry, as well as outstanding high-rate capability in aqueous electrolytes. [28][29][30][31][32] As reported by Wessells et al, [29] the NiHCF material can be stably cycled in acidic NaNO 3 with a reversible capacity of about 60 mAh g À1 and an average operating potential of 0.59 V (vs SHE), achieving a rate capacity of about 40 mAh g À1 at 41.7 C and a capacity retention of above 98 % after 1000 cycles. As exhibited by Wu et al, [33] it delivers discharge capacities of 65 mAh g À1 at 1 C and 63 mAh g À1 at 5 C in neutral Na 2 SO 4 electrolyte, with a slight capacity decay after 500 cycles.…”

Nanocrystal‐Assembled Porous Na3MgTi(PO4)3 Aggregates as Highly Stable Anode for Aqueous Sodium‐Ion Batteries

“…Unlike in organic ester/ ether-based electrolytes, mostN a-storage materials are not suitable electrodes for aqueous SIBs owing to the limitation of the voltage window defined by the potentials of H 2 evolution and O 2 evolution, as well as the chemical instability and electrochemical irreversibility in aqueous solutions. [31][32][33][34][35][36][37][38] However,t here is still lack of an anode material with good cycling stability for aqueousS IBs. 44 6 ]h ave demonstrated excellent cycling performance as cathode for aqueous SIBs.…”