Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries

Boeun Lee, Hyo Ree Seo, Hae Ri Lee, Chong Seung Yoon, Jong Hak Kim, Kyung Yoon Chung, Byung Won Cho, Si Hyoung Oh

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

The reaction mechanism of α-MnO2 having 2×2 tunnel structure with zinc ions in a zinc rechargeable battery, employing an aqueous zinc sulfate electrolyte, was investigated by in situ monitoring structural changes and water chemistry alterations during the reaction. Contrary to the conventional belief that zinc ions intercalate into the tunnels of α-MnO2, we reveal that they actually precipitate in the form of layered zinc hydroxide sulfate (Zn4(OH)6(SO4)⋅5 H2O) on the α-MnO2 surface. This precipitation occurs because unstable trivalent manganese disproportionates and is dissolved in the electrolyte during the discharge process, resulting in a gradual increase in the pH value of the electrolyte. This causes zinc hydroxide sulfate to crystallize from the electrolyte on the electrode surface. During the charge process, the pH value of the electrolyte decreases due to recombination of manganese on the cathode, leading to dissolution of zinc hydroxide sulfate back into the electrolyte. An analogous phenomenon is also observed in todorokite, a manganese dioxide polymorph with 3×3 tunnel structure that is an indication for the critical role of pH changes of the electrolyte in the reaction mechanism of this battery system.

Original languageEnglish
Pages (from-to)2948-2956
Number of pages9
JournalChemSusChem
Volume9
Issue number20
DOIs
Publication statusPublished - 2016 Oct 20

Fingerprint

electrolyte
Electrolytes
Zinc
zinc
sulfate
Sulfates
Manganese
hydroxide
manganese
Tunnels
tunnel
todorokite
Ions
Zinc Sulfate
Secondary batteries
ion
battery
Polymorphism
structural change
water chemistry

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Chemical Engineering(all)
  • Materials Science(all)
  • Energy(all)

Cite this

Lee, Boeun ; Seo, Hyo Ree ; Lee, Hae Ri ; Yoon, Chong Seung ; Kim, Jong Hak ; Chung, Kyung Yoon ; Cho, Byung Won ; Oh, Si Hyoung. / Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries. In: ChemSusChem. 2016 ; Vol. 9, No. 20. pp. 2948-2956.
@article{b4864a3da8fd45e48e713968ba6c4cdf,
title = "Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries",
abstract = "The reaction mechanism of α-MnO2 having 2×2 tunnel structure with zinc ions in a zinc rechargeable battery, employing an aqueous zinc sulfate electrolyte, was investigated by in situ monitoring structural changes and water chemistry alterations during the reaction. Contrary to the conventional belief that zinc ions intercalate into the tunnels of α-MnO2, we reveal that they actually precipitate in the form of layered zinc hydroxide sulfate (Zn4(OH)6(SO4)⋅5 H2O) on the α-MnO2 surface. This precipitation occurs because unstable trivalent manganese disproportionates and is dissolved in the electrolyte during the discharge process, resulting in a gradual increase in the pH value of the electrolyte. This causes zinc hydroxide sulfate to crystallize from the electrolyte on the electrode surface. During the charge process, the pH value of the electrolyte decreases due to recombination of manganese on the cathode, leading to dissolution of zinc hydroxide sulfate back into the electrolyte. An analogous phenomenon is also observed in todorokite, a manganese dioxide polymorph with 3×3 tunnel structure that is an indication for the critical role of pH changes of the electrolyte in the reaction mechanism of this battery system.",
author = "Boeun Lee and Seo, {Hyo Ree} and Lee, {Hae Ri} and Yoon, {Chong Seung} and Kim, {Jong Hak} and Chung, {Kyung Yoon} and Cho, {Byung Won} and Oh, {Si Hyoung}",
year = "2016",
month = "10",
day = "20",
doi = "10.1002/cssc.201600702",
language = "English",
volume = "9",
pages = "2948--2956",
journal = "ChemSusChem",
issn = "1864-5631",
publisher = "Wiley-VCH Verlag",
number = "20",

}

Lee, B, Seo, HR, Lee, HR, Yoon, CS, Kim, JH, Chung, KY, Cho, BW & Oh, SH 2016, 'Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries', ChemSusChem, vol. 9, no. 20, pp. 2948-2956. https://doi.org/10.1002/cssc.201600702

Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries. / Lee, Boeun; Seo, Hyo Ree; Lee, Hae Ri; Yoon, Chong Seung; Kim, Jong Hak; Chung, Kyung Yoon; Cho, Byung Won; Oh, Si Hyoung.

In: ChemSusChem, Vol. 9, No. 20, 20.10.2016, p. 2948-2956.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Critical Role of pH Evolution of Electrolyte in the Reaction Mechanism for Rechargeable Zinc Batteries

AU - Lee, Boeun

AU - Seo, Hyo Ree

AU - Lee, Hae Ri

AU - Yoon, Chong Seung

AU - Kim, Jong Hak

AU - Chung, Kyung Yoon

AU - Cho, Byung Won

AU - Oh, Si Hyoung

PY - 2016/10/20

Y1 - 2016/10/20

N2 - The reaction mechanism of α-MnO2 having 2×2 tunnel structure with zinc ions in a zinc rechargeable battery, employing an aqueous zinc sulfate electrolyte, was investigated by in situ monitoring structural changes and water chemistry alterations during the reaction. Contrary to the conventional belief that zinc ions intercalate into the tunnels of α-MnO2, we reveal that they actually precipitate in the form of layered zinc hydroxide sulfate (Zn4(OH)6(SO4)⋅5 H2O) on the α-MnO2 surface. This precipitation occurs because unstable trivalent manganese disproportionates and is dissolved in the electrolyte during the discharge process, resulting in a gradual increase in the pH value of the electrolyte. This causes zinc hydroxide sulfate to crystallize from the electrolyte on the electrode surface. During the charge process, the pH value of the electrolyte decreases due to recombination of manganese on the cathode, leading to dissolution of zinc hydroxide sulfate back into the electrolyte. An analogous phenomenon is also observed in todorokite, a manganese dioxide polymorph with 3×3 tunnel structure that is an indication for the critical role of pH changes of the electrolyte in the reaction mechanism of this battery system.

AB - The reaction mechanism of α-MnO2 having 2×2 tunnel structure with zinc ions in a zinc rechargeable battery, employing an aqueous zinc sulfate electrolyte, was investigated by in situ monitoring structural changes and water chemistry alterations during the reaction. Contrary to the conventional belief that zinc ions intercalate into the tunnels of α-MnO2, we reveal that they actually precipitate in the form of layered zinc hydroxide sulfate (Zn4(OH)6(SO4)⋅5 H2O) on the α-MnO2 surface. This precipitation occurs because unstable trivalent manganese disproportionates and is dissolved in the electrolyte during the discharge process, resulting in a gradual increase in the pH value of the electrolyte. This causes zinc hydroxide sulfate to crystallize from the electrolyte on the electrode surface. During the charge process, the pH value of the electrolyte decreases due to recombination of manganese on the cathode, leading to dissolution of zinc hydroxide sulfate back into the electrolyte. An analogous phenomenon is also observed in todorokite, a manganese dioxide polymorph with 3×3 tunnel structure that is an indication for the critical role of pH changes of the electrolyte in the reaction mechanism of this battery system.

UR - http://www.scopus.com/inward/record.url?scp=84988422108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84988422108&partnerID=8YFLogxK

U2 - 10.1002/cssc.201600702

DO - 10.1002/cssc.201600702

M3 - Article

C2 - 27650037

AN - SCOPUS:84988422108

VL - 9

SP - 2948

EP - 2956

JO - ChemSusChem

JF - ChemSusChem

SN - 1864-5631

IS - 20

ER -