Rocking-Chair Proton Batteries with Conducting Redox Polymer Active Materials and Protic Ionic Liquid Electrolytes.

Huan Wang,Patric Jannasch,Christoffer Karlsson,Rikard Emanuelsson,Martin Sjödin,Maria Strømme

doi:10.1021/acsami.1c01353

Huan Wang, Patric Jannasch + Show 4 more

Open Access

https://doi.org/10.1021/acsami.1c01353

Copy DOI

Abstract

Rechargeable batteries that use redox-active organic compounds are currently considered an energy storage technology for the future. Functionalizing redox-active groups onto conducting polymers to make conducting redox polymers (CRPs) can effectively solve the low conductivity and dissolution problems of redox-active compounds. Here, we employ a solution-processable postdeposition polymerization (PDP) method, where the rearrangements ensured by partial dissolution of intermediated trimer during polymerization were found significant to produce high-performance CRPs. We show that quinizarin (Qz)- and naphthoquinone (NQ)-based CRPs can reach their theoretical capacity through optimization of the polymerization conditions. Combining the two CRPs, with the Qz-CRP as a cathode, the NQ-CRP as an anode, and a protic ionic liquid electrolyte, yields a 0.8 V proton rocking-chair battery. The conducting additive-free all-organic proton battery exhibits a capacity of 62 mAh/g and a capacity retention of 80% after 500 cycles using rapid potentiostatic charging and galvanostatic discharge at 4.5 C.

Highlights

The development of large-scale power systems such as electric vehicles and smart grids escalates the demand for energy storage technologies, such as batteries
Formation of a Soluble Trimer Radical Cation upon Neutral State Trimer Oxidation, (iii) Competition between Trimer Radical Coupling and Diffusion to the Bulk Solution, and (iv) Oligomer Redeposition react with water through Michael addition.[31−35] By replacing the water solvent, it should be possible to increase the stability of proton batteries by suppressing the Michael addition reaction. This could be done in organic protic electrolytes[36] or using nonstoichiometric protic ionic liquids,[37] which could allow a potential window over 1.23 V.38−40 We have previously shown that the use of nonaqueous solvents significantly extends the possibility to tune quinone redox potentials by substitution since, in aqueous solutions, specific interactions with water molecules counteract the effect of substituents.[41]
The prepared trimer film was polymerized using postdeposition polymerization (PDP),[29] which allows the full utilization of starting materials as opposed to traditional polymerization from a monomer solution, where most starting materials remain unreacted

Summary

INTRODUCTION

The development of large-scale power systems such as electric vehicles and smart grids escalates the demand for energy storage technologies, such as batteries. Formation of a Soluble Trimer Radical Cation upon Neutral State Trimer Oxidation, (iii) Competition between Trimer Radical Coupling and Diffusion to the Bulk Solution, and (iv) Oligomer Redeposition react with water through Michael addition.[31−35] By replacing the water solvent, it should be possible to increase the stability of proton batteries by suppressing the Michael addition reaction This could be done in organic protic electrolytes[36] or using nonstoichiometric protic ionic liquids,[37] which could allow a potential window over 1.23 V.38−40 We have previously shown that the use of nonaqueous solvents significantly extends the possibility to tune quinone redox potentials by substitution since, in aqueous solutions, specific interactions with water molecules counteract the effect of substituents.[41] protic ionic liquids may provide a solution for redox-active materials that show poor wettability in water electrolytes. A conducting additive-free all-organic proton rocking-chair battery was thereby fabricated (Scheme 1)

RESULTS AND DISCUSSION

BATTERY PERFORMANCE

CONCLUSIONS

■ REFERENCES