Evaluating the Polymer Backbone – Vinylene versus Styrene – of Anisyl‐substituted Phenothiazines as Battery Electrode Materials

Abstract

Organic electrode materials are capable candidates for nextgeneration greener energy storage solutions. One advantage is that their electrochemical performance can be tuned by structural modification. We herein investigate anisyl-substituted poly(vinyl-) and poly(styrylphenothiazines) as positive electrode materials for dual-ion batteries. π-Interactions -characteristic to phenothiazine redox polymers -are facilitated in the poly(styrene) derivatives PSAPT and PSAPT-X-DVB due to the longer spacing between phenothiazine units and polymer backbone and lead to high cycling stabilities, but reduce their specific capacities. In the poly(vinylenes), the linear PVAPT shows high cycling stability but a dissolution/redeposition mechanism, diminishing its capacity, while the cross-linked X-PVAPT demonstrates high cycling stabilities at specific capacities up to 81 mAh g À 1 paired with an excellent rate performance, where 10,000 cycles at 100 C rate proceed with 86 % capacity retention.

Ferrocene Appended Porphyrin‐Based Bipolar Electrode Material for High‐Performance Energy Storage

“…From cycles (10 th →20 th ), highly reversible CVs were recorded with a slight shift to lower potential (Figure 2a). This behaviour accounts for the increase in electrical conductivity of the material upon cycling, [24] which has been further verified by electrochemical impedance spectroscopy (EIS), in which the charge‐transfer resistance of the CuDEFcP electrode has reduced after the initial cycle (Figure S31).…”

Unlocking twofold oxidation in phenothiazine polymers for application in symmetric all-organic anionic batteries

“…Aryl substituents can assume an intra (quasi-equatorial) or extra (quasi-axial) conformation relative to the PT core. 66 The intra conformation is energetically favorable for most aryl substituents except strongly electron-withdrawing ones, and was also found to be preferred for TDMPT and TPT, albeit by only a small energy amount for TDMPT (−0.14 kcal mol −1 ; see Table S4 in the ESI).…”

“…37 Attaching an electron-donating aryl substituent to the N-atom, however, has a comparably small effect on the redox potential of PT. 66,67 PT and its analogues usually show good solubility in polar organic solvents, including battery electrolytes. Hence, to achieve immobilization, PT was attached to a polystyrene backbone.…”

“…The crosslinked derivatives were synthesized as previous studies have shown that linear PT-based polymers tend to be soluble in battery electrolytes in their oxidized form. 66,69,70 Linear PSDMPT exhibits a theoretical specific capacity of Qtheo = 148.3 mAh g −1 for a two-electron transfer.…”

Unlocking twofold oxidation in phenothiazine polymers for application in symmetric all-organic anionic batteries

“…37 Attaching an electron-donating aryl substituent to the N-atom, however, has a comparably small effect on the redox potential of PT. 67,68 PT and its analogues usually show good solubility in polar organic solvents, including battery electrolytes. Hence, to achieve immobilization, PT was attached to a polystyrene backbone.…”