Salt-concentrated acetate electrolytes for a high voltage aqueous Zn/ MnO2 battery

Shigang  Chen; Rong Lan; John Humphreys; Shanwen Tao

doi:10.1016/j.ensm.2020.03.011

Salt-concentrated acetate electrolytes for a high voltage aqueous Zn/ MnO2 battery

Shigang Chen, Rong Lan, John Humphreys, Shanwen Tao

University of Warwick

Research output: Contribution to journal › Article › peer-review

154 Citations (Scopus)

Abstract

Aqueous rechargeable Zn/MnO ₂ batteries are attractive due to their low-cost, high safety and use of non-toxic materials. In term of electrolyte materials, it is anticipated that an aqueous electrolyte with a wider electrochemical window will improve the stability and energy density. In this work, we investigated salt-concentrated electrolytes based on relatively inexpensive acetate salts. An electrochemical window of 3.4 V was achieved in salt-concentrated 1 m Zn(OAc) ₂+31 m KOAc electrolyte. Its total ionic conductivity is 2.96 × 10 ^-2 S cm ^-1 while the ionic conductivity of Zn ²⁺ ions is 7.80 × 10 ^-3 S cm ^-1, estimated by a current interrupt method. This electrolyte is regarded as a mild alkaline environment with a pH value of 9.76, causing the different storage mechanism for anode with Zn ²⁺ ions and, cathode with OH ^- ions as the charge carriers respectively. A Zn/MnO ₂ battery was assembled using 1 m Zn(OAc) ₂+31 m KOAc electrolyte, self-supported α-MnO ₂-TiN/TiO ₂ cathode and Zn foil anode. The Zn/MnO ₂ battery can be charged to 2.0 V versus Zn/Zn ²⁺ and delivers discharge capacity and energy density of 304.6 mAh·g ^-1 (calculated on the mass of MnO ₂) or 0.32 mAh·cm ^-2 (calculated on the area of electrode) and, 368.5 Wh·kg ^-1 (calculated on the mass of MnO ₂) or 232.7 Wh·kg ^-1 (calculated on the total active mass of electrodes and electrolyte) in the first cycle under a current density of 100 mA·g ^-1 (~ C/3, based on the mass of MnO ₂) or 0.1 mA·cm ^-2 (based on the area of electrode). During cycling, the coulombic efficiency can be maintained around 99% and reached 99.9% during the 14-340th cycles. After the cycling tests, almost no dendrites were observed on the Zn foil anode attributing to the super-high salt concentration in that acetate-based electrolyte, which will benefit the stability of aqueous Zn/MnO ₂ batteries.

Original language	English
Pages (from-to)	205-215
Number of pages	11
Journal	Energy Storage Materials
Volume	28
Early online date	14 Mar 2020
DOIs	https://doi.org/10.1016/j.ensm.2020.03.011
Publication status	Published - Jun 2020

Keywords

Aqueous rechargeable battery
Zn/MnO2
Acetates
Salt-concentrated electrolytes
WiBSE
Zn/MnO

ASJC Scopus subject areas

Energy Engineering and Power Technology
Materials Science(all)
Renewable Energy, Sustainability and the Environment

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.ensm.2020.03.011

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@article{f62ffac2e50748eabee463ad42e3c0eb,

title = "Salt-concentrated acetate electrolytes for a high voltage aqueous Zn/ MnO2 battery",

abstract = "Aqueous rechargeable Zn/MnO 2 batteries are attractive due to their low-cost, high safety and use of non-toxic materials. In term of electrolyte materials, it is anticipated that an aqueous electrolyte with a wider electrochemical window will improve the stability and energy density. In this work, we investigated salt-concentrated electrolytes based on relatively inexpensive acetate salts. An electrochemical window of 3.4 V was achieved in salt-concentrated 1 m Zn(OAc) 2+31 m KOAc electrolyte. Its total ionic conductivity is 2.96 × 10 -2 S cm -1 while the ionic conductivity of Zn 2+ ions is 7.80 × 10 -3 S cm -1, estimated by a current interrupt method. This electrolyte is regarded as a mild alkaline environment with a pH value of 9.76, causing the different storage mechanism for anode with Zn 2+ ions and, cathode with OH - ions as the charge carriers respectively. A Zn/MnO 2 battery was assembled using 1 m Zn(OAc) 2+31 m KOAc electrolyte, self-supported α-MnO 2-TiN/TiO 2 cathode and Zn foil anode. The Zn/MnO 2 battery can be charged to 2.0 V versus Zn/Zn 2+ and delivers discharge capacity and energy density of 304.6 mAh·g -1 (calculated on the mass of MnO 2) or 0.32 mAh·cm -2 (calculated on the area of electrode) and, 368.5 Wh·kg -1 (calculated on the mass of MnO 2) or 232.7 Wh·kg -1 (calculated on the total active mass of electrodes and electrolyte) in the first cycle under a current density of 100 mA·g -1 (~ C/3, based on the mass of MnO 2) or 0.1 mA·cm -2 (based on the area of electrode). During cycling, the coulombic efficiency can be maintained around 99% and reached 99.9% during the 14-340th cycles. After the cycling tests, almost no dendrites were observed on the Zn foil anode attributing to the super-high salt concentration in that acetate-based electrolyte, which will benefit the stability of aqueous Zn/MnO 2 batteries. ",

keywords = "Aqueous rechargeable battery, Zn/MnO2, Acetates, Salt-concentrated electrolytes, WiBSE, Zn/MnO",

author = "Shigang Chen and Rong Lan and John Humphreys and Shanwen Tao",

year = "2020",

month = jun,

doi = "10.1016/j.ensm.2020.03.011",

language = "English",

volume = "28",

pages = "205--215",

journal = "Energy Storage Materials",

issn = "2405-8297",

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T1 - Salt-concentrated acetate electrolytes for a high voltage aqueous Zn/ MnO2 battery

AU - Chen, Shigang

AU - Lan, Rong

AU - Humphreys, John

AU - Tao, Shanwen

PY - 2020/6

Y1 - 2020/6

N2 - Aqueous rechargeable Zn/MnO 2 batteries are attractive due to their low-cost, high safety and use of non-toxic materials. In term of electrolyte materials, it is anticipated that an aqueous electrolyte with a wider electrochemical window will improve the stability and energy density. In this work, we investigated salt-concentrated electrolytes based on relatively inexpensive acetate salts. An electrochemical window of 3.4 V was achieved in salt-concentrated 1 m Zn(OAc) 2+31 m KOAc electrolyte. Its total ionic conductivity is 2.96 × 10 -2 S cm -1 while the ionic conductivity of Zn 2+ ions is 7.80 × 10 -3 S cm -1, estimated by a current interrupt method. This electrolyte is regarded as a mild alkaline environment with a pH value of 9.76, causing the different storage mechanism for anode with Zn 2+ ions and, cathode with OH - ions as the charge carriers respectively. A Zn/MnO 2 battery was assembled using 1 m Zn(OAc) 2+31 m KOAc electrolyte, self-supported α-MnO 2-TiN/TiO 2 cathode and Zn foil anode. The Zn/MnO 2 battery can be charged to 2.0 V versus Zn/Zn 2+ and delivers discharge capacity and energy density of 304.6 mAh·g -1 (calculated on the mass of MnO 2) or 0.32 mAh·cm -2 (calculated on the area of electrode) and, 368.5 Wh·kg -1 (calculated on the mass of MnO 2) or 232.7 Wh·kg -1 (calculated on the total active mass of electrodes and electrolyte) in the first cycle under a current density of 100 mA·g -1 (~ C/3, based on the mass of MnO 2) or 0.1 mA·cm -2 (based on the area of electrode). During cycling, the coulombic efficiency can be maintained around 99% and reached 99.9% during the 14-340th cycles. After the cycling tests, almost no dendrites were observed on the Zn foil anode attributing to the super-high salt concentration in that acetate-based electrolyte, which will benefit the stability of aqueous Zn/MnO 2 batteries.

AB - Aqueous rechargeable Zn/MnO 2 batteries are attractive due to their low-cost, high safety and use of non-toxic materials. In term of electrolyte materials, it is anticipated that an aqueous electrolyte with a wider electrochemical window will improve the stability and energy density. In this work, we investigated salt-concentrated electrolytes based on relatively inexpensive acetate salts. An electrochemical window of 3.4 V was achieved in salt-concentrated 1 m Zn(OAc) 2+31 m KOAc electrolyte. Its total ionic conductivity is 2.96 × 10 -2 S cm -1 while the ionic conductivity of Zn 2+ ions is 7.80 × 10 -3 S cm -1, estimated by a current interrupt method. This electrolyte is regarded as a mild alkaline environment with a pH value of 9.76, causing the different storage mechanism for anode with Zn 2+ ions and, cathode with OH - ions as the charge carriers respectively. A Zn/MnO 2 battery was assembled using 1 m Zn(OAc) 2+31 m KOAc electrolyte, self-supported α-MnO 2-TiN/TiO 2 cathode and Zn foil anode. The Zn/MnO 2 battery can be charged to 2.0 V versus Zn/Zn 2+ and delivers discharge capacity and energy density of 304.6 mAh·g -1 (calculated on the mass of MnO 2) or 0.32 mAh·cm -2 (calculated on the area of electrode) and, 368.5 Wh·kg -1 (calculated on the mass of MnO 2) or 232.7 Wh·kg -1 (calculated on the total active mass of electrodes and electrolyte) in the first cycle under a current density of 100 mA·g -1 (~ C/3, based on the mass of MnO 2) or 0.1 mA·cm -2 (based on the area of electrode). During cycling, the coulombic efficiency can be maintained around 99% and reached 99.9% during the 14-340th cycles. After the cycling tests, almost no dendrites were observed on the Zn foil anode attributing to the super-high salt concentration in that acetate-based electrolyte, which will benefit the stability of aqueous Zn/MnO 2 batteries.

KW - Aqueous rechargeable battery

KW - Zn/MnO2

KW - Acetates

KW - Salt-concentrated electrolytes

KW - WiBSE

KW - Zn/MnO

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U2 - 10.1016/j.ensm.2020.03.011

DO - 10.1016/j.ensm.2020.03.011

M3 - Article

SN - 2405-8297

VL - 28

SP - 205

EP - 215

JO - Energy Storage Materials

JF - Energy Storage Materials

ER -

Salt-concentrated acetate electrolytes for a high voltage aqueous Zn/ MnO2 battery

Abstract

Keywords

ASJC Scopus subject areas

UN SDGs

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