Enabling the conventional TFSI-based electrolytes for high-performance Mg/Li hybrid batteries by Mg electrode interfacial regulation

The Mg-metal batteries (MMBs) as a forceful competitor for Li-metal batteries (LMBs) have the advantages of high-safety and high-volume energy density . Whereas, the MMBs still confronts two vital issues to be addressed, including the incompatibility of conventional TFSI-based electrolytes with the Mg electrode and the poor reversibility of the cathode. In this work, to satisfyingly settle the incompatibility, an artificial interphase was first pre-constructed by high-temperature displacement reaction of CuCl 2 and Mg metal, responsible for the faster charge-transfer rate and the lower Mg plating/stripping overpotential (∼0.2 V) in Mg symmetric cells. Regarding the Mg-Mo 6 S 8 full cells, to enhance the reversibility and rate performance, Mg/Li hybrid batteries were designed. Consequently, the Mg-Mo 6 S 8 battery can achieve excellent cycle stability and deliver a desirable capacity. Even as the current density increases to 1C, the battery still shows a desirable capacity of 92 mAh g −1 over 500 cycles.