Synthetic control of manganese birnessite: Impact of crystallite size on Li, Na, and Mg based electrochemistry

Synthesis of Mg-birnessite (MgxMnO2) with different crystallite sizes via low temperature precipitation and ion exchange was demonstrated. The influence of crystallite size on electrochemistry of Mg-birnessite was studied for the first time. Material with smaller crystallite size showed enhanced capacity and rate capability in Li+, Na+, and Mg2+ based electrolytes.81