Insights into temperature-induced evolution of spinel MnCo2O4 as anode material for Li-ion batteries with enhanced electrochemical performance.

The mechanism of non-stoichiometric MnCo 2 O 4+δ to stoichiometric MnCo 2 O 4 structural transformation in the calcination temperature range of 350–650 °C and its morphology evolution from nanoplates with {112} facets to quasi nanoplates with {110} facets in the preferential orientation of [220] direction is investigated in detail and confirmed using XPS, HRTEM, TGA, and XRD analysis. By having a profound understanding of this mechanism, MnCo 2 O 4 with a well-controlled structure and morphology was synthesized via co-precipitation as the anode for Li-ion batteries to overcome the capacity fading issue. Moreover, the anode microstructure was optimized based on the correlation between Li+ storage, electrode durability, and interfacial resistance through the electrochemical response of electrode components, including MnCo 2 O 4 , carbon black, and binder. The optimum electrode exhibited a high initial discharge capacity of 2063 mAh g−1 at 400 mA g−1, excellent rate capability (807 mAh g−1 at 1000 mA g−1), and outstanding cycling performance (709 mAh g−1 at 400 mA g−1 after 150 cycles). These are attributed to the balance between the high surface area and robust architecture of MnCo 2 O 4 , and the stability, conductivity, and porosity of the electrode. [Display omitted] • Phase studies show that increasing the temperature to 650 °C resulted in the evacuation of excess oxygen in MnCo 2 O 4+δ. • By increasing the temperature, {112} facets alter to {110} facets in the preferential orientation of [220] direction. • The optimized electrode exhibited a stable reversible capacity of 709.5 mAh g−1 over 150 cycles at 400 mA g−1. [ABSTRACT FROM AUTHOR]