Effect of Binding Affinity of Crystal Water on the Electrochemical Performance of Layered Double Hydroxides

Abstract

The ever‐increasing demand for safe batteries has driven research efforts to develop aqueous rechargeable batteries. In this regard, Ni‐based layered double hydroxides (LDHs) have received marked attention owing to their adequate operating potential, high specific capacity, and decent cycling performance. Nevertheless, the effect of immobile intercalants (e. g., crystal water and anions) that are inherently present in the interlayer galleries is barely understood. In this paper, we report that the electrochemical performance of LDH largely depends on the extent to which the crystallinity is affected by the binding strength of crystal water to the transition metal slabs. A series of infrared spectroscopy and in‐situ X‐ray absorption analyses reveal that the lattice disordering in LDHs is beneficial for accommodating the stress during the (de)intercalation of carrier ions, which serves as the origin of their superior specific capacities and cycle life. This study presents a useful structure‐property relationship of the way in which the binding affinity of crystal water affects the key electrochemical properties of the host electrode materials.

The Missing Piece: The Structure of the Ti3C2Tx MXene and Its Behavior as Negative Electrode in Sodium Ion Batteries

“…This, combined with the higher surface area due to the open-lamellar structure, can be identified as the source of the higher irreversibility in the first cycle and in the lower capacity retention observed for MXT-30 with respect to MXT-5 (Figure a). A similar correlation among the higher degree of crystallinity and better stability has already been pointed out for layered materials . Thus, the overall outstanding reversibility of the MXT-5 as Na ion intercalation material can be associated with the favorable distance among the layer and the presence of stacking faults, providing a mechanism for the relief of the stress upon sodiation and desodiation cycles, as already highlighted for similar layered compounds …”

“…A similar correlation among the higher degree of crystallinity and better stability has already been pointed out for layered materials. 45 Thus, the overall outstanding reversibility of the MXT-5 as Na ion intercalation material can be associated with the favorable distance among the layer and the presence of stacking faults, providing a mechanism for the relief of the stress upon sodiation and desodiation cycles, as already highlighted for similar layered compounds. 46 ■ ASSOCIATED CONTENT * sı Supporting Information…”

Turning Berlin green frameworks into cubic crystals for cathodes with high-rate capability

“…S8 †). 53 Given the limited amount of potassium ions in both samples, the negligible capacity (<2.5 mA h g −1 ) delivered in the first charging process is omitted for better visualization (Fig. S9 †).…”

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“…Consequently, the difference between the ideal and practical catalytic sites makes it difficult to clearly and deeply clarify the practical mechanism during the reaction. Therefore, integrating in situ characterizations (such as XRD, XANES, and Raman spectra) into the clarification of practical physicochemical properties of catalytic sites is necessary. − For example, the surface reconstruction is widely recognized for transition metal chalcogenides. Wang et al reported the generation of α-Ni­(OH) 2 and γ-NiOOH phase from NiS 0.5 Se 0.5 under the OER condition, which was characterized by in situ Raman spectroscopy (Figure a) .…”