Phenothiazine-based Redox Polymers for Energy Storage

Otteny, Fabian; Desmaizieres, Gauthier; Esser, Birgit

doi:10.1039/9781788019743-00166

Cited by 9 publications

(12 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It can be therefore concluded that the change of solvents drastically influenced the solubility of the polymer during cycling as well as the interactions of adjacent PVMPT units. Possible explanations for this behavior might be related to the change in molecular structure between DMC and EMC, which includes their symmetry, their molecular weight, and their relative permittivity (ε DMC = 3.11 and ε EMC = 2.96). , …”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Insights into the Solubility of Poly(vinylphenothiazine) in Carbonate-Based Battery Electrolytes

Perner

Diddens

Otteny

et al. 2021

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Organic materials are promising candidates for next-generation battery systems. However, many organic battery materials suffer from high solubility in common battery electrolytes. Such solubility can be overcome by introducing tailored high-molecular-weight polymer structures, for example, by crosslinking, requiring enhanced synthetic efforts. We herein propose a different strategy by optimizing the battery electrolyte to obtain insolubility of non-cross-linked poly(3-vinyl-N-methylphenothiazine) (PVMPT). Successive investigation and theoretical insights into carbonate-based electrolytes and their interplay with PVMPT led to a strong decrease in the solubility of the redox polymer in ethylene carbonate/ethyl methyl carbonate (3:7) with 1 M LiPF 6 . This allowed accessing its full theoretical specific capacity by changing the charge/discharge mechanism compared to previous reports. Through electrochemical, spectroscopic, and theoretical investigations, we show that changing the constituents of the electrolyte significantly influences the interactions between the electrolyte molecules and the redox polymer PVMPT. Our study demonstrates that choosing the ideal electrolyte composition without chemical modification of the active material is a successful strategy to enhance the performance of organic polymer-based batteries.

show abstract

Section: Resultsmentioning

confidence: 99%

“…This work focuses on a non-cross-linked redox polymer which contains methyl-phenothiazine (MPT) side groups attached to a poly(vinylene) backbone . Poly(3-vinyl- N -methylphenothiazine) ( PVMPT ) was studied intensively over the last years and revealed an outstanding cycling stability and rate capability .…”

Section: Introductionmentioning

confidence: 99%

Insights into the Solubility of Poly(vinylphenothiazine) in Carbonate-Based Battery Electrolytes

Perner

Diddens

Otteny

et al. 2021

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…We have intensively investigated phenothiazine-based redox polymers as positive electrode materials in recent years. ,− Due to the high reversibility and fast kinetics of the oxidation of the phenothiazine group, such polymers can show outstanding cycling stabilities and rate capabilities . Using aliphatic polymer backbones, however, the intrinsic conductivity in the polymer is low (transport through hopping processes), and thick electrodes with high mass loadings of active polymer are challenging to obtain.…”

Section: Introductionmentioning

confidence: 99%

“…18,29−34 Due to the high reversibility and fast kinetics of the oxidation of the phenothiazine group, such polymers can show outstanding cycling stabilities and rate capabilities. 35 Using aliphatic polymer backbones, however, the intrinsic conductivity in the polymer is low (transport through hopping processes), and thick electrodes with high mass loadings of active polymer are challenging to obtain. A conjugated polymer backbone offers advantages in this respect, as has, for instance, been shown by combining polythiophenes with redox-active nitroxide radical side groups.…”

Section: ■ Introductionmentioning

confidence: 99%

Conjugated Copolymer Design in Phenothiazine-Based Battery Materials Enables High Mass Loading Electrodes

Acker

Wössner

Desmaizieres

et al. 2022

ACS Sustainable Chem. Eng.

Self Cite

View full text Add to dashboard Cite

Organic electrode materials are considered to be promising candidates for alternative and greener energy storage solutions. Due to their intrinsic low conductivity, however, usually large amounts of conductive additives are required for electrode fabrication. Herein, we investigate electrodes with a 90 wt % active material ratio and high mass loadings of up to 4.3 mg cm–2, which show good cycling performance because of the conjugated copolymer structure chosen for the phenothiazine-based active material. By furthermore reducing the inactive weight within the polymer through structural modification and raising the potential range during constant current measurements we increased the discharge capacity for the whole composite by a factor of 12 to 0.169 mAh cm–2 compared to a previous study. This study demonstrates that conjugated organic copolymers are attractive electrode materials due to their intrinsic conductivity combined with the presence of defined redox centers.

show abstract

“…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.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Phenothiazine-based Redox Polymers for Energy Storage

Cited by 9 publications

References 70 publications

Insights into the Solubility of Poly(vinylphenothiazine) in Carbonate-Based Battery Electrolytes

Insights into the Solubility of Poly(vinylphenothiazine) in Carbonate-Based Battery Electrolytes

Conjugated Copolymer Design in Phenothiazine-Based Battery Materials Enables High Mass Loading Electrodes

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

Contact Info

Product

Resources

About