Lin Wang1 Samuel Welborn1 Hemant Kumar Kumar1 Vivek Shenoy1 Eric Detsi1

1, Univ of Pennsylvania, Philadelphia, Pennsylvania, United States

Resources used in lithium-ion batteries are becoming more expensive due to demand, and the global cobalt market heavily depends on supplies from countries with high geopolitical risks. Alternative battery technologies including magnesium-ion batteries are therefore desirable. Progress toward practical magnesium-ion batteries have been impeded by an absence of suitable anodes that can operate with conventional electrolyte solvents. Although alloy-type magnesium-ion battery anodes are compatible with common electrolyte solvents, they suffer from severe failure associated with huge volume changes during cycling. Consequently, achieving more than 200 cycles in alloy-type magnesium-ion battery anodes remains a challenge [1]. In this talk I will an unprecedented long-cycle life of 1000 cycles, achieved at a relatively high (dis)charge rate of 3C (current density: 922.5 mA/g) in Mg2Ga5 alloy-type anode, taking advantage of near-room-temperatures solid-liquid phase transformations between Ga(liquid) and Mg2Ga5(solid)[2]. A combination of Finite-Element Modelling (FEM), electrochemical characterization, and operando wide-angle X-ray scattering (WAXS) is used to investigate this remarkable cycling performance[2]. This concept should open the way to the development of practical anodes for the next generation magnesium-ion batteries.

Keywords: Beyond lithium, Magnesium-ion battery anode, self-healing, solid-liquid phase transformation, operando X-ray scattering.

[1] Y. Cheng, Y. Shao, L.R. Parent, M.L. Sushko, G. Li, N.D. Browning, C. Wang and J. Liu:
Interface promoted reversible Mg insertion in nanostructured tin-antimony alloys Adv. Mater. 27, 6598-6605 (2015).

[2] L. Wang, S.S. Welborn, H. Kumar, Z. Wang, M. Li, V. Shenoy, and E. Detsi:
High-Rate and Long Cycle-Life Alloy-Type Magnesium-Ion Battery Anode Enabled through (De)magnesiation-Induced Near-Room-Temperature Solid-Liquid Phase Transformation
Under Review (2019)