Solvothermal synthesis and electrochemical charge storage assessment of Mn3N2

η-Mn3N2 is produced using solvothermal reactions between MnCl2 and LiNH2 in benzene. At 350 °C nanocapsule structures are obtained, whereas at higher temperatures samples consisted of isotropic nanoparticulates. In aqueous KOH solution capacitances of up to 300 F g (2 mV s, potential window 0.3 to -0.6 V vs Hg/HgO), but capacitance fell to relatively low values on cycling. In lithium cells a reversible first cycle capacity of 600 mA h g was obtained, and this decayed to 340 mA h g after 50 cycles. In sodium cells a reversible first cycle capacity of 156 mA h g was obtained and was maintained well on cycling (127 mA h g in the 50 cycle).