Flame-retarding battery cathode materials based on reversible multi-electron redox chemistry of phenothiazine-based polymer

Lv, Jing; Ye, Jing; Dai, Gaole; Niu, Zhihui; Sun, Yi; Zhang, Xiaohong

doi:10.1016/j.jechem.2020.02.017

Cited by 20 publications

(20 citation statements)

References 55 publications

(44 reference statements)

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“…For S2p spectra, in spite of the existed oxidized sulfur species (SO x ) in pristine electrode, the obvious proportion increase of peaks at higher binding energy (168.5 and 169.7 eV) to those at lower binding energy (164.5 and 165.7 eV) indicated that a minority of neutral sulfur atoms (‐S‐) were electrochemically oxidized to positively charged one (‐S + ‐). Combining the analysis for N1s and S2p spectra, we could draw a conclusion that the positive charge was delocalized in the conjugated phenothiazine unit but mainly taken by the N atom rather than S atom, in good agreement with previous assumptions [26] . For Cl2p spectra, peaks at 208.6 and 210.2 eV suddenly appeared in the charged electrode and completely disappeared in the discharged electrode, which was a strong evidence of highly reversible ClO 4 − doping/dedoping behavior.…”

Section: Resultssupporting

confidence: 87%

“…The most well‐known p‐type organic cathode materials are conducting polymers (e. g., polyaniline, [11,12] polytriphenylamine, [13] and polypyrrole [14] ) and nitroxyl radical polymers (e. g., PTMA [15] ). In recent years, researchers’ interest also shifts to polymers based on various electroactive heteroaromatics, including N ‐substituted phenazine, [16–19] conjugated pyridine dimer, [20] phenothiazine, [18,21–31] phenoxazine, [32] and thianthrene [33,34] . A merit of these heteroaromatic units is that they are potentially able to deliver two electrons and thus achieve attractive capacity above 200 mAh g −1 .…”

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Polyphenothiazine as a High‐Performance p‐Type Cathode for Rechargeable Lithium Batteries

Wang

Han

et al. 2021

ChemSusChem

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p‐Type electroactive polymers are promising cathodes for dual‐ion batteries but cost‐effective candidates are still lacking. In this study, the p‐type polymer polyphenothiazine (PPTZ) is synthesized by a facile one‐step oxidation polymerization from the low‐cost phenothiazine (PTZ) monomer. As a cathode for rechargeable lithium batteries, PPTZ shows superior electrochemical performance to previously reported PTZ‐based polymers with complicated structures and syntheses. For example, PPTZ has a high reversible capacity of 157 mAh g−1 within 2.5–4.3 V vs. Li+/Li with an average discharge voltage of 3.5 V, and a high capacity retention of 77 % after 500 cycles. The highly reversible one‐electron redox mechanism of PPTZ is also investigated in detail by electrochemical testing, ex situ FT‐IR and X‐ray photoelectron spectroscopy, and DFT calculations. PPTZ has the potential to serve as an attractive p‐type cathode material for practical applications and the facile synthesis may be also extended to other polymer cathodes based on N‐heteroaromatic units.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Polyphenothiazine as a High‐Performance p‐Type Cathode for Rechargeable Lithium Batteries

Wang

Han

et al. 2021

ChemSusChem

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“…Totally, we generate 47 structures, but not all of them are novel. Among these structures, three of them were reported previously in our work, which are (1) DPPZ, 21 (2) PhPT, 31 and (3) DPICZ, 32 which strengthened the availability of our work, as shown in Figure 1b. These examples denoted that the generation on high-potential structures preferred benzene rings and some specific functional groups by joining rings and a nitrogen atom.…”

Section: Oobsupporting

confidence: 84%

Machine Learning-Assisted Discovery of High-Voltage Organic Materials for Rechargeable Batteries

Liang

et al. 2021

J. Phys. Chem. C

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Organic redox compounds are rich in elements and structural diversity, which are an ideal choice for lithium-ion batteries. However, most organic cathode materials show a trade-off between specific capacity and voltage, limiting energy density. By increasing the redox potential of cathode materials, the balance between redox potential and specific capacity can be broken to increase energy density. In this work, we use machine learning to train materials with different redox potentials to predict novel polymers with ideal potentials. In situ computer vision and infrared spectroscopy monitor the reaction in real time. We also theoretically studied the concentrationdependent yields by providing a depletion-force model. This work provides a new solution to material research flow, including training, prediction, synthesis, examination, and analysis, accelerating high-capacity organic cathode material discovery.

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“…In 2017, we introduced poly(3-vinyl- N -methylphenothiazine) ( PVMPT ) as a positive electrode material . This was the third report of a phenothiazine-based polymer investigated as electrode material , and has been followed by other studies on different polymer architectures since then. − Phenothiazine can be reversibly oxidized to a radical cation during charge, which in PVMPT -based cells occurs at a potential of 3.5 V vs Li/Li + .…”

Section: Introductionmentioning

confidence: 99%

Bridging the Gap between Small Molecular π-Interactions and Their Effect on Phenothiazine-Based Redox Polymers in Organic Batteries

Otteny

Perner

Einholz

et al. 2021

ACS Appl. Energy Mater.

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Organic redox polymers are considered a “greener” alternative as battery electrode materials compared to transition metal oxides. Among these, phenothiazine-based polymers have attracted significant attention due to their high redox potential of 3.5 V vs Li/Li+ and reversible electrochemistry. In addition, phenothiazine units can exhibit mutual π-interactions, which stabilize their oxidized states. In poly(3-vinyl-N-methylphenothiazine) (PVMPT), such π-interactions led to a unique charge/discharge mechanism, involving the dissolution and redeposition of the polymer during cycling, and resulted in an ultrahigh cycling stability. Herein, we investigate these π-interactions in more detail and what effect their suppression by molecular design has on battery performance. Our study includes a dimeric reference compound for PVMPT, polymers with bulky tolyl or mesityl substituents on the phenothiazine units to inhibit π-interactions and alternating copolymers with maleimide groups to increase spatial distancing between phenothiazine groups. UV/vis- and electron paramagnetic resonance (EPR)-spectroscopic as well as electrochemical measurements in composite electrodes demonstrate how the unique structure of PVMPT is instrumental in obtaining a high cycling stability in poly(vinylene) derivatives of phenothiazine.

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Flame-retarding battery cathode materials based on reversible multi-electron redox chemistry of phenothiazine-based polymer

Cited by 20 publications

References 55 publications

Facile Synthesis of Polyphenothiazine as a High‐Performance p‐Type Cathode for Rechargeable Lithium Batteries

Facile Synthesis of Polyphenothiazine as a High‐Performance p‐Type Cathode for Rechargeable Lithium Batteries

Machine Learning-Assisted Discovery of High-Voltage Organic Materials for Rechargeable Batteries

Bridging the Gap between Small Molecular π-Interactions and Their Effect on Phenothiazine-Based Redox Polymers in Organic Batteries

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