Electrochemical performance of Mg electrolytes is highly sensitive to water and other impurities. The water sensitivity of a MgCl₂/AlCl₃ electrolyte in DME was demonstrated, showing increased overpotential and poor Coulombic efficiency for Mg deposition. Mg powder treatment was found to be very effective and convenient to remove deleterious impurities present in MgCl₂/AlCl₃ electrolytes to yield unprecedented electrochemical performance for reversible Mg deposition including 100% Coulombic efficiency, low overpotential (< 200 mV), and high anodic stability (up to 3.8 V). It is also found the Mg powder scavenger is also effective for other Mg electrolytes, highlighting the generality of the Mg powder treatment approach. The working mechanism of the Mg powder scavenger will be discussed. In addition, we will show that ternary Mg/MgCl₂/AlCl₃ (MMAC) electrolytes are reliable for Mg battery applications.

References:

(1) Luo, J; .He, S.; Liu, T. L.* ACS Energy Letters 2017, 2, 1197-1202.

(2) He, S.; Luo, J. Liu, T. L.*, J. Mater. Chem. A 2017, 12718-12722.

(3) He, S.; Neilson, K. V.; Luo, J..; Liu, T. L.*, Energy Storage Mater 2017, 8, 184-188.