Issue 31, 2021

Intercalation/deintercalation of solvated Mg2+ into/from graphite interlayers


In the development of rechargeable Mg-ion batteries which are not limited by resource constraints, studies on negative electrode materials have been concentrated on efficient Mg-deposition/stripping rather than on insertion/extraction-type active materials, driven by the extremely high theoretical capacity of Mg metal (2205 mA h g−1). This work re-examined the potential of graphite, which is overlooked in electrochemical tests using a two-electrode type cell due to a large overpotential during sluggish Mg-deposition/stripping at the counter electrode caused by the passivation layer. The formation of a graphite intercalation compound (GIC) with a stage structure was demonstrated by the continual application of a constant current without considering the cut-off voltage to eliminate the detrimental impact of the counter electrode, although the intercalant was solvated Mg-ions. The GIC formed during the charging process has a blue tint just like a GIC synthesized by a vapor method. Although there is still issue with the large polarization during the deintercalation of solvated Mg ions, a reversible capacity of approximately 200 mA h g−1 could be achieved in the galvanostatic charge/discharge tests with a current density of 7.44 mA g−1. The results should facilitate future research and development of graphite as a negative electrode material.

Graphical abstract: Intercalation/deintercalation of solvated Mg2+ into/from graphite interlayers

Supplementary files

Article information

Article type
26 Jun 2021
26 Jul 2021
First published
27 Jul 2021
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2021,23, 16981-16988

Intercalation/deintercalation of solvated Mg2+ into/from graphite interlayers

M. Shimizu, A. Nakahigashi and S. Arai, Phys. Chem. Chem. Phys., 2021, 23, 16981 DOI: 10.1039/D1CP02895B

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