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

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 beta-Al(2)O(3)electrolyte. Herein, a Li(6.4)La(3)Zr(1.4)Ta(0.6)O(12)solid-electrolyte-based molten lithium-molybdenum-iron(II) chloride battery (denoted as Li-Mo-FeCl2) operated at temperature of 250 degrees 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-FeCl(2)battery surpasses that of a Na-FeCl(2)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 g(LiCl)(-1)after 300 cycles, 50 mg active material) and strong tolerance against the overcharge-overdischarge (3-1.6 V) and freezing-thawing (25-250 degrees C) incidents.