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High interfacial charge storage capability of carbonaceous cathodes for Mg batteries

Abstract

A rechargeable Mg battery where the capacity mainly originates from reversible reactions occurring at the electrode/electrolyte interface efficiently avoids the challenge of sluggish Mg intercalation encountered in conventional Mg batteries. The interfacial reactions in a cell based on microwave-exfoliated graphite oxide (MEGO) as the cathode and all phenyl complex (APC) as electrolyte are identified by quantitative kinetics analysis as a combination of diffusion-controlled reactions involving ether solvents (esols) and capacitive processes. During magnesiation, esols in APC electrolytes can significantly affect the electrochemical reactions and charge transfer resistances at the electrode/electrolyte interface and thus govern the charge storage properties of the MEGO cathode. In APC–tetrahydrofuran (THF) electrolyte, MEGO exhibits a reversible capacity of ∼220 mAh g–1 at 10 mA g–1, while a reversible capacity of ∼750 mAh g–1 at 10 mA g–1 was obtained in APC-1,2-dimethoxyethane (DME) electrolyte. The high capacity improvement not only points to the important role of the esols in the APC electrolytes but also presents a Mg battery with high interfacial charge storage capability as a very promising and viable competitor to the conventional intercalation-based batteries.
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Category

Academic article

Language

English

Author(s)

Affiliation

  • SINTEF Industry / Materials and Nanotechnology
  • Norwegian University of Science and Technology
  • China

Year

2018

Published in

ACS Nano

ISSN

1936-0851

Volume

12

Issue

3

Page(s)

2998 - 3009

View this publication at Norwegian Research Information Repository