Spinel-layered integrate structured nanorods with both high capacity and superior high-rate capability as cathode material for lithium-ion batteries

Abstract

Spinel phase LiMn2O4 was successfully embedded into monoclinic phase layeredstructured Li2MnO3 nanorods, and these spinel-layered integrate structured nanorods showed both high capacities and superior high-rate capabilities as cathode material for lithium-ion batteries (LIBs). Pristine Li2MnO3 nanorods were synthesized by a simple rheological phase method using α-MnO2 nanowires as precursors. The spinel-layered integrate structured nanorods were fabricated by a facile partial reduction reaction using stearic acid as the reductant. Both structural characterizations and electrochemical properties of the integrate structured nanorods verified that LiMn2O4 nanodomains were embedded inside the pristine Li2MnO3 nanorods. When used as cathode materials for LIBs, the spinel-layered integrate structured Li2MnO3 nanorods (SL-Li2MnO3) showed much better performances than the pristine layered-structured Li2MnO3 nanorods (L-Li2MnO3). When charge–discharged at 20 mA·g−1 in a voltage window of 2.0–4.8 V, the SL-Li2MnO3 showed discharge capacities of 272.3 and 228.4 mAh·g−1 in the first and the 60th cycles, respectively, with capacity retention of 83.8%. The SL-Li2MnO3 also showed superior high-rate performances. When cycled at rates of 1 C, 2 C, 5 C, and 10 C (1 C = 200 mA·g−1) for hundreds of cycles, the discharge capacities of the SL-Li2MnO3 reached 218.9, 200.5, 147.1, and 123.9 mAh·g−1, respectively. The superior performances of the SL-Li2MnO3 are ascribed to the spinel-layered integrated structures. With large capacities and superior high-rate performances, these spinel-layered integrate structured materials are good candidates for cathodes of next-generation high-power LIBs.