On the controlled electrochemical preparation of R4N+ graphite intercalation compounds and their host structural deformation effects

Abstract

a b s t r a c tWe present electrochemical studies of tetraalkylammonium (R 4 N + ) reduction chemistry at Highly Orientated Pyrolytic Graphite (HOPG) and glassy carbon (GC) electrodes. We show that by electrochemically controlled intercalation and formation of a graphite intercalation complex (GIC) into layered HOPG, the irreversible reduction of the tetraalkylammonium cation can be prevented and subsequent deintercalation of the GIC via the use of potentiostatic control is achievable. R 4 N + cations with varying alkyl chain lengths (methyl, ethyl and butyl) have been shown to exhibit excellent charge recovery effects during charge/discharge studies. Finally the effects of electrode expansion on the degree of recovered charge have been investigated and the observed effects of R 4 N + intercalation on the graphite cathode have been probed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Stabilization of Black Phosphorus by Sonication‐Assisted Simultaneous Exfoliation and Functionalization

“…The increased amount of few‐layer flakes with large lateral dimensions for BP exfoliated in the presence of TBAFP under minimal sonication indicates that it acts as an intercalating agent that facilitates exfoliation, in agreement with theoretical studies, [17] although prolonged sonication promotes separation of the layers and aids intercalation [14b] . TBA salts have been used for graphene intercalation due to the flexibility of the n ‐butyl chains, [19a,d] while the butyl chain length is optimal for BP intercalation compared to tetramethyl‐ and tetraoctylammonium cations [18b] . The flattened configuration of TBA has a diameter of 0.47 nm, which closely matches the 0.53 nm interlayer spacing of BP, and also allows efficient intercalation [18b, 28] .…”

“…The absence of a discernible contribution to the P 2p peak associated with PF 6 − indicates that TBAFP does not passivate the surface, but rather TBA interacts with the surface. TBA salts have been reported to facilitate exfoliation [32] and have also been employed as intercalation agents [19a–d] . Therefore TBA may play a similar role in the exfoliation of BP, which was evaluated by carrying out a stepwise exfoliation–functionalization procedure by immersion in a solution of TBAFP, followed by minimal sonication (10 min) to separate BP layers and subsequent functionalization with IBF.…”

Efficient Graphene Production by Combined Bipolar Electrochemical Intercalation and High-Shear Exfoliation

“…Other salts could also have been used for graphite intercalation. 13,17,18 Figure 1c shows a significant expansion of the cathodic end (left side) of the graphite foil. The expansion is expected to occur from the intercalation of Bu 4 N + at the cathodic end (left side) of the electrode with the oxidation of NMP taking place at the anodic end.…”

Electrochemically Exfoliated High‐Quality 2H‐MoS2 for Multiflake Thin Film Flexible Biosensors

“…TBA·HSO 4 is highly soluble in a wide cast of organic solvents, providing great freedom for the electrolyte design. Because the size of TBA + cation (0.85 nm) is generally greater than the interlayer spacing of MoS 2 layers (0.615 nm), the expansion at the boundaries of MoS 2 crystal is necessary to allow the intercalation of large TBA + cations. A low positive bias of +5 V was applied on the MoS 2 foils for 5 min, to intercalate small anions (SO 4 2− ), for the subsequent intercalation by cationic TBA + .…”