Charge storage mechanism of MnO2 cathodes in Zn/MnO2 batteries using ionic liquid-based gel polymer electrolytes

• Published in: Electrochemistry communications Vol. 60; pp. 190 - 194
• Main Authors: Tafur, Juan P., Abad, José, Román, Elisa, Fernández Romero, Antonio J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2015
• Subjects: Ionic liquid-based gel polymer electrolytes; MnO2 cathode; XPS; Zinc batteries; MnO2 cathode; XPS; Ionic liquid-based gel polymer electrolytes; Zinc batteries
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2015.09.011

Cathode reactions in Zn/MnO2 batteries using aqueous electrolytes have been usually interpreted by the reduction of Mn4+ to Mn3+ while protons and/or cations penetrate inside the cathode. However, until now, the MnO2 storage charge mechanism using a non-aqueous gel polymer electrolyte (GPE) has not been investigated. In this work, ionic liquid-based GPEs including BMIM Tf and ZnTf2 have been employed in Zn/MnO2 batteries. Different states of charge of MnO2 cathodes used in Zn/IL-GPE/MnO2 batteries have been analyzed by XPS and EDX techniques. XPS analysis showed that Mn4+ is reduced during the discharge process at the same time as Zn2+ cations are incorporated into the cathode. Besides, Zn2+ cations insertion is accompanied by triflate anions. [Display omitted] •MnO2 charge storage mechanism in a Zn/IL-GPE/MnO2 battery is analyzed.•XPS analysis demonstrated that Mn4+ is reduced to Mn2+ during discharging.•Zn2+ cations are incorporated into the cathode accompanied by triflate anions.•Mn2+ species are expulsed to the GPE during the discharge process.