MgMn
2O
4 was synthesized by employing the Pechini sol-gel method [13 (
link)]. Specifically, a solution containing 0.5 M Mg(NO
3)
2·6H
2O (VWR chemicals BHD, 99%, Leuven, Belgium), 1.0 M Mn(NO
3)
2·4H
2O (Sigma Aldrich, 97%, St. Louis, MO, USA) in 5 mL
ethylene glycol (Sigma Aldrich, 99.8%) and 5 mL H
2O was stirred for 30 min. The
citric acid (Sigma Aldrich) was then added to obtain a 3.0 M solution, which was stirred for 1 h.
The solution was maintained at 70 °C for 24 h, triggering the generation of a brown gel, which was next thermally treated in an oven at 200 °C for 12 h. The resulting black solid was ground and heated at 400 °C in the air for 10 h. The MgMn
2O
4 spinels doped with either cobalt or nickel were synthesized in the same way but adding to the precursor solution 1.6 mmol of Co(NO
3)
2·6H
2O (Sigma Aldrich, 98%) in the case of the Co-doped spinel and 1.6 mmol of Ni(NO
3)
2·6H
2O (Sigma Aldrich, 97%) for the Ni-doped spinel.
Miralles C., Lana-Villarreal T, & Gómez R. (2023). Unraveling the Phase Transition Behavior of MgMn2O4 Electrodes for Their Use in Rechargeable Magnesium Batteries. Materials, 16(15), 5402.