Tailoring the electrochemical activity of magnesium chromium oxide towards Mg batteries through control of size and crystal structure

Abstract

Reversible Mg removal from MgCr2O4 (a high-voltage Mg-intercalation cathode material) was improved by nanosizing and introducing significant structural defects.

Reversible High Capacity and Reaction Mechanism of Cr2(NCN)3 Negative Electrodes for Li‐Ion Batteries

“…The spectrum of component 1 overlaps with that of the pristine Cr 2 (NCN). Moreover, the pre‐edge doublet seen around ≈5993 eV is commonly observed for Cr 3+ , in line with the attribution of component 1 to pristine Cr 2 (NCN) 3 . The slight shift toward lower energies observed on going to component 2 testifies the reduction of Cr 3+ to Cr 2+ , which is again consistent with the Cr 3+ –Cr 2+ –Cr 0 pathway predicted by theoretical calculations (vide supra ) .…”

Direct Nano‐Synthesis Methods Notably Benefit Mg‐Battery Cathode Performance

“…This strategy has been implemented to activate Li + insertion into olivine LiMnPO 4 [ 33,34 ] and to improve the electrochemistry of other Li‐ion [ 35–42 ] as well as Mg electrode materials. [ 43–47 ] Nanomaterials can either be prepared (1) directly through rapid, low‐temperature syntheses that limit the growth of crystallites or (2) by mechanical milling of micron‐sized materials. While a wide variety of synthetic methods have been developed to directly prepare nano‐sized oxide and binary sulfide materials, most ternary sulfides are prepared with a high‐temperature solid state synthesis that produces micron‐sized particles.…”

Enhanced charge storage of nanometric ζ-V2O5 in Mg electrolytes

“…[10][11][12][13] In contrast, oxide materials can offer much higher potentials vs. Mg/Mg 2+ , e.g. 2.5 V for V 2 O 5 , 14,15 2.9 V for MgMn 2 O 4 , 16 and 3.5 V for MgCr 2 O 4 , 14,15,[17][18][19] although these materials typically exhibit Mg insertion and removal kinetics that are moderateto-poor (e.g. overpotentials of >0.7 V for V 2 O 5 , corresponding to ∼70% energy efficiency).…”

“…The use of CHFS enabled the production of nano-sized crystallites via highly supersaturating conditions and a short reaction time (residence time on the order of a few seconds), 25,26 and the process has previously produced a wide variety of high-performance nanosized electrode materials for Mg batteries, Liion batteries and supercapacitors. 17,[27][28][29][30][31] Experimental section…”