"A Garnet-Type Solid-Electrolyte-Based Molten Lithium−Molybdenum−Iron(II) Chloride Battery with Advanced Reaction Mechanism"

Jing Xu: Kai Liu, Yang Jin, Bin Sun, Zili Zhang, Yi Chen, Dawei Su, Guoxiu Wang, Hui Wu, and Yi Cui; Advanced Materials, 06/23/20.

Additional Authors: Kai Liu, Yang Jin, Bin Sun, Zili Zhang, Yi Chen, Dawei Su, Guoxiu Wang, Hui Wu, and Yi Cui

Abstract:

Solid-electrolyte-based molten-metal batteries have attracted considerable attention for grid-scale energy storage. Although ZEBRA batteries are considered one of the promising candidates, they still have the potential concern of metal particle growth and ion exchange with the β”-Al2O3 electrolyte. Herein, a Li6.4La3Zr1.4Ta0.6O12 solid-electrolyte-based molten lithium−molybdenum−iron(II) chloride battery (denoted as Li−Mo−FeCl2) operated at temperature of 250 °C, comprising a mixture of Fe and LiCl cathode materials, a Li anode, a garnet-type Li-ion ceramic electrolyte, and Mo additive, is designed to overcome these obstacles. Different from conventional battery reaction mechanisms, this battery revolutionarily synchronizes the reversible Fe−Mo alloying−dealloying reactions with the delithiation−lithiation processes, meaning that the porous Mo framework derived from Fe−Mo alloy simultaneously suppresses the growth of pure Fe particles. By adopting a Li anode and a Li-ion ceramic electrolyte, the corrosion problem between the cathode and the solid electrolyte is overcome. With similar battery cost ($12 kWh−1), the theoretical energy density of Li−Mo−FeCl2 battery surpasses that of a Na−FeCl2 ZEBRA battery over 25%, to 576 Wh kg−1 and 2216 Wh L−1, respectively. Experimental results further prove this cell has excellent cycling performance (472 mAh gLiCl−1 after 300 cycles, 50 mg active material) and strong tolerance against the overcharge− overdischarge (3−1.6 V) and freezing−thawing (25−250 °C) incidents.