125th General Meeting of the KCS

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Type Oral Presentation
Area Oral Presentation for Young Material Chemists
Room No. Room 303 (Live Streaming)
Time TUE 10:45-11:00
Code MAT.O-8
Subject XMg/Mg2Sn: Phase controlled synthesis and high-performance anode materials for magnesium-ion batteries
Authors Amol Bhairuba Ikhe, Myoungho Pyo*
Department of Printed Electronics Engineering, Suncheon National University, Korea
Abstract Nowadays, rechargeable magnesium ion batteries (MIB) have gained increasing attention as a promising battery systems alternative to lithium-based batteries for grid-scale energy storage. Mg, as an anode material which inherently possesses a number of merits over the alkali metals such as lithium/potassium is safe to use without dendritic growth, high crustal abundant, low cost, and high theoretical volumetric capacity (3833mAh/cm3). However, the passivating behaviors of the Mg in common electrolytes are still challenging. Herein, we show that XMg/Mg2Sn can be used as high capacity anode with excellent rate-capability and cyclability in MIBs. As-made XMg/Mg2Sn consists of crystalline Mg-rich (c-Mg), amorphous Mg-rich (a-Mg), and intermetallic Mg2Sn phases. During the 1st de-magnesiation of XMg/Mg2Sn in conventional magnesium electrolytes, c-Mg is first de-alloyed. After complete dealloying of c-Mg, a-Mg and intermetallic Mg2Sn phases is subsequently de-magnesiated at slightly higher potentials, resulting in a discharge capacity of 1243 mAhg-1 (3.9Mg2+) at 100 mAg-1. Following charge/discharge (C/D) reversibly delivers 805 mAh-1 (2.5Mg2+), which indicates most capacities from Sn ⇄ Mg2Sn and additional capacities from a-Mg. Once de-alloyed, c-Mg is not involved in a reversible magnesiation/de-magnesiation process. Instead, it provides meso-to-macro porosity to an active material, which eventually contributes to the high-rate capability (540 mAhg-1 at 1000 mAg-1). XMg/Mg2Sn also shows a reasonable stability (90% retention after 100 C/D) and compatibility with various conventional electrolytes. Furthermore, XMg/Mg2Sn could be an optimal anode when coupled with partially Mg2+-trapping cathodes (e.g., Mo6S8), because irreversible Mg2+ ions that are released from c-Mg can be balanced with trapped Mg2+ in Mo6S8 during the 1st discharge.
E-mail ikheamol@gmail.com