Lu, C.-H.C.-H.LuWang, H.-C.H.-C.WangCHUNG-HSIN LU2020-01-062020-01-062004https://scholars.lib.ntu.edu.tw/handle/123456789/444808Ultrafine orthorhombic LiMnO2 (o-LiMnO2) were successfully synthesized using a newly developed reverse-microemulsion (RμE) process. To prepare o-LiMnO2 powers with a rock salt structure, precise control of the oxygen content in the heating atmosphere was required. Monophasic o-LiMnO2 was obtained at as low as 700°C. Not only the reaction temperature was lowered, the reaction duration for synthesizing the desired powders was also markedly shortened via the RμE route. The average particle size of the 900°C-calcined powders was measured to be around 90 nm. The discharge capacities of the prepared o-LiMnO2 powders significantly increased in the initial stages, and rapidly reached a saturated plateau. The impedance spectroscopy analysis revealed that the chemical diffusion coefficient of lithium ions in o-LiMnO2 was markedly greater than that in LiMn2O4-based materials. The high diffusion rate of lithium ions in o-LiMnO2 is attributed to the high crystallinity as well as the nanosize of the powders synthesized via this RμE process. © 2003 Elsevier Ltd. All rights reserved.Electrochemical impedance spectroscopy; Lithium manganese oxide; Lithium-ion batteries; Orthorhombic structure; Reverse-microemulsion process[SDGs]SDG7Diffusion; Lithium batteries; Microemulsions; Salts; Synthesis (chemical); Impedance spectroscopy; Reverse-microemulsion; Powder metals; powderjournal article10.1016/S0955-2219(03)00332-72-s2.0-0242456304https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242456304&doi=10.1016%2fS0955-2219%2803%2900332-7&partnerID=40&md5=92e2690515a5a565f213dd7c58eaa5fc