Journal of Inorganic Materials, Volume. 37, Issue 2, 173(2022)
Magnesium metal batteries (MMBs) have attracted increasing attention due to the high volume specific capacity (3833 mAh/cm3) and high safety of Mg metal anode. Nevertheless, the high polarization effect induced by Mg2+ inhibits its diffusion in solid phase and therefore limits the specific capacity of MMBs. Li+/Mg2+ dual-salt electrolyte has been proposed to circumvent the sluggish diffusion of Mg2+ in solid phase, which enables Li+ to replace Mg2+ to drive the cathode reaction. In this work, the electrochemical performance of CoS2 as conversion cathode of MMBs is studied based on different Li+/Mg2+ dual-salt electrolytes, and the effects of Li-salt concentration and discharge-charge voltage range on cycling stability are analyzed. The strategy of Li-salt additive remarkably promotes the conversion kinetics of CoS2 based MMBs. By developing charge voltage to 2.75 V, the cycling stability of Mg-CoS2 cell in LiCl-APC electrolyte is significantly enhanced. Its specific capacity can be maintained at 275 mAh/g after 150 cycles, which is much higher than that (33 mAh/g) under the protocol of 2.0 V charge voltage. It is found that the capacity degradation of MMBs is related to the irreversible reaction of CoS2 and generation of Co3S4 at the charge potential of 2.0 V. And the dissolution of Co and S elements from active species aggravates the irreversible loss of capacity. This study provides an electrochemical activation solution to the development of transition metal sulfides in conversion type MMBs.
Get Citation
Copy Citation Text
Wenbo LI, Minsong HUANG, Yueming LI, Chilin LI.
Category:
Received: Jun. 4, 2021
Accepted: --
Published Online: Nov. 14, 2022
The Author Email: