Suppressing Electrolyte Decomposition at Cathode/Electrolyte Interface by Mg-Fe Binary Oxide Coating towards Room-Temperature Magnesium Rechargeable Battery Operation

Abstract

For practical room-temperature magnesium rechargeable battery operation, utilizing the nano-sized MgMn 2 O 4 spinel as cathode material is effective way to have high rate-capabilities; however, electrolyte decomposition at the cathode/electrolyte interface is inevitable. In this work, a Mg-Fe binary oxide is coated onto nano-sized MgMn 2 O 4 to form stable cathode electrolyte interface (CEI). This developed cathode material suppresses the electrolyte decomposition and improves the cyclability at room temperature.

Ultraporous, Ultrasmall MgMn2O4 Spinel Cathode for a Room-Temperature Magnesium Rechargeable Battery

“…Figure f shows the discharge/charge cycles of the MMO treated at 300 °C. We previously confirmed the electrolyte decomposition at the same cell test condition by XPS analysis . Although the decomposition of electrolyte occurred competitively during overcharge, but we performed the cell test with the voltage range of 0.1–4.0 V to proceed the oxidation reaction.…”

“…43,44 The on-site Coulomb correction (GGA+U) was used to describe the localized electronic states in the Mn 3d orbital (U Mn,d = 3.9 eV 45 ). The nudged elastic band (NEB) method 46 19,36 (n-Bu) 4 NMnO 4 was prepared according to a previous report. 47 2 mmol of (n-Bu) 4 NMnO 4 powder was first slowly added to a 2 mmol MgCl 2 solution made in a 25 mL ethanol and 25 mL diglyme mixture under vigorous stirring for 1 h. Ten milliliters of water was then injected to the brown colloidal solution, precipitating the MMO.…”

“…MgMn 2 O 4 (MMO) was prepared using the modified alcohol reduction process. , ( n -Bu) 4 NMnO 4 was prepared according to a previous report . 2 mmol of ( n -Bu) 4 NMnO 4 powder was first slowly added to a 2 mmol MgCl 2 solution made in a 25 mL ethanol and 25 mL diglyme mixture under vigorous stirring for 1 h. Ten milliliters of water was then injected to the brown colloidal solution, precipitating the MMO.…”

“…We previously confirmed the electrolyte decomposition at the same cell test condition by XPS analysis. 36 Although the decomposition of electrolyte occurred competitively during overcharge, but we performed the cell test with the voltage range of 0.1−4.0 V to proceed the oxidation reaction. The discharge capacity gradually decreases due to the side reaction of electrolyte decomposition at the charge step; the cathode can be well cycled using the high-voltage stable electrolyte.…”

Spray-Dried MgMn2O4 Spinel Oxide Cathode with Single Mg Ion-Conductive Polymers for Rechargeable Mg Metal Battery

“…It is reported that these problems can be overcome by coating the active material of the cathode. Coating materials used in the Mg cathode are reduced graphene oxide (rGO), V 2 O 4 , NH 4 VO 3 , phenylphosphonate, , Mg-Fe binary oxide, and further coating materials for MMB identified by computational analysis . These coating materials also achieved improved cycling ability.…”