Microstructure and electrochemical characterization of spherical-like orthorhombic LiMnO2 via co-precipitation

Spherical-like morphology orthorhombic LiMnO2 (So-LiMnO2) powders were prepared using spherical-like MnCO3 precursors, which were obtained by a carbonate co-precipitation method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) method. Non-spherical orthorhombic LiMnO2 (No-LiMnO2) powders were also studied and compared with the above-mentioned So-LiMnO2. The results show that the microstructure of o-LiMnO2 depends significantly on that of the precursors. The obtained So-LiMnO2 has a poor crystalline structure, more stacking faults and small crystallites that have morphology similar to that of powders consisting of larger particles. Benefiting from its unique microstructure, the So-LiMnO2 cathode exhibits a higher maximum capacity and better capacity retention compared to that of No-LiMnO2. The analyses performed with a transmission electron microscopy (TEM) and an energy dispersive spectroscopy (EDS), confirmed that So-LiMnO2 particle, formed by the agglomeration of primary particles, can reduce the erosion of positive material by electrolytes and the dissolution of manganese, which results in the enhanced electrochemical cycleability.