One-step hydrothermal synthesis of LiMn2O4 cathode materials for rechargeable lithium batteries

•LiMn2O4 was prepared by one-step hydrothermal reaction.•Particle size decreased with an increase in hydrothermal temperature.•Appropriate particle size improved the electrochemical performance of LiMn2O4.

LiMn2O4 cathode materials with high discharge capacity and good cyclic stability were prepared by a simple one-step hydrothermal treatment of KMnO4, aniline and LiOH solutions at 120–180 °C for 24 h. The aniline/KMnO4 molar ratio (R) and hydrothermal temperature exhibited an obvious influence on the component and phase structures of the resulting product. The precursor KMnO4 was firstly reduced to birnessite when R was less than 0.2:1 at 120–150 °C. Pure-phased LiMn2O4 was formed when R was 0.2:1, and the LiMn2O4 was further reduced to Mn3O4 when R was kept in the range of 0.2–0.3 at 120–150 °C. Moreover, LiMn2O4 was fabricated when R was 0.15:1 at 180 °C. Octahedron-like LiMn2O4 about 300 nm was prepared at 120 °C, and particle size decreased with an increase in hydrothermal temperature. Especially, LiMn2O4 synthesized at 150 °C exhibited the best electrochemical performance with the highest initial discharge capacity of 127.4 mAh g−1 and cycling capacity of 106.1 mAh g−1 after 100 cycles. The high discharge capacity and cycling stability of the as-prepared LiMn2O4 cathode for rechargeable lithium batteries were ascribed to the appropriate particle size and larger cell volume.

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