Characteristics of ZnMn₂O₄ nanopowders prepared by flame spray pyrolysis for use as anode material in lithium ion batteries

ZnMn₂O₄ nanopowders with homogeneous composition are prepared by flame spray pyrolysis from an aqueous spray solution containing Zn and Mn components. The ZnMn₂O₄ powders subjected to post-treatment at 500°C exhibit a mean size of 65 nm and nonaggregation characteristics. The discharge capacities of the precursor powder and the ZnMn₂O₄ powders post-treated at 400, 500, and 600°C are 1156, 1230, 1192, and 1086 mAh g^-1, respectively, after 40 cycles at a current density of 300 mA g^-1, and the corresponding capacity retentions measured after the first cycle are 69, 75, 78, and 79%. The ZnMn₂O₄ nanopowders post-treated at 500°C exhibit high initial discharge and charge capacities of 1192 and 632 mAh g^-1, respectively, at a current density of 1000 mA g^-1. The discharge capacity of the powders decreases from 1192 to 470 mAh g^-1 during the first 15 cycles, and then becomes stable at values above 450 mAh g^-1 until 110 cycles. Subsequently, the discharge capacities of the ZnMn₂O₄ nanopowders increase gradually from the 110^th cycle onward. The maximum discharge capacity reaches 670 mAh g^-1 after 160 cycles.