Investigation of sodium insertion into tetracyanoquinodimethane (TCNQ): results for a TCNQ thin film obtained by a surface science approach

Abstract

In this contribution, we investigate the insertion of sodium into tetracyanoquinodimethane (TCNQ) and its effect on the electronic structure by means of a surface science experiment. We exposed a TCNQ thin film stepwise to sodium vapour and monitored the electronic structure by X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). During the insertion experiment three stages were observed, which can be related to three different phases, predominantly consisting of TCNQ(0), TCNQ(1-) and TCNQ(2-). With increasing sodium content the Fermi level shifts upwards and new electronic states appear in the band gap. For phases with high sodium content the sodium diffusion seems to be inhibited which we attribute to closed diffusion pathways in the molecular structure of TCNQ(1-).

Evidence of double layer/capacitive charging in carbon nanomaterial-based solid contact polymeric ion-selective electrodes

“…S10b) revealed a peak at 1072.5 eV that is representative of Na + in an ionic salt (viz., NaTFPB). 25 The aforesaid SR-XPS core level chemical states are also consistent with the formation of an electrical double layer of adsorbed/absorbed Na + and TFPB ions within the capacitively charged f-MWCNT SC layer. Figure 2a presents the VB spectra for the PVC/f-MWCNT SC electrode following electrochemical charging of the system to induce an ion-exchange of NaTFPB from the membrane into the f-MWCNT film after removal of the plasticized PVC membrane by sputtering for 8 minutes which correspond to approximately 96 nm in depth (note that the membrane was thinner than in Figure 1).…”

Advanced Organic Electrode Materials for Rechargeable Sodium‐Ion Batteries

“…[26] Reversible tautomerism is expected to occur on these derivatives. Further In addition to the CN double bonds, tetracyanoethylene [101,102] and tetracyanoquinodimethane (TCNQ) [103] with CN bond have also been investigated as a cathode for SIB. Further In addition to the CN double bonds, tetracyanoethylene [101,102] and tetracyanoquinodimethane (TCNQ) [103] with CN bond have also been investigated as a cathode for SIB.…”

Recent Progress in Advanced Organic Electrode Materials for Sodium‐Ion Batteries: Synthesis, Mechanisms, Challenges and Perspectives

“…Schiff and pteridine derivatives containing CN bond has an adjustable electrochemical activity, in which plane structure and conjugated structure play an important role in stabilizing their electrochemical activity. [56][57][58][59][60][61] Azo compounds containing NN bonds are newly recognized as electrode materials for OSIBs; the experimental results show that the NN bond acts as an electrochemical activity groups to reversibly bond with Na ions. [62] Through reasonable design of their structures, there is great room for further development.…”