Ion Exchange Reactions for Synthesis of Nano-Sized Lithium and Sodium Manganese Phospho-Olivines as Cathode Materials in Lithium and Sodium Ion Batteries

摘要

Nowadays phospho-olivines with compositions L1MPO4 (M = Fe, Mn, Co and Ni) are attracted both research and technological interest as electrode materials for lithium ion batteries with potential application in the hybrid electric vehicles (1, 2). This interest is motivated by the many advantages of these compounds: reasonably high capacity (170mAhg~(-1)) and cyclic stability, tolerance to overcharge, excellent safety and low cost. More recently, in response to the current requirements for the development of cheaper "green" batteries the replacement of lithium with sodium becomes very attractive (3). Since the thermodynamically stable NaMPO4 does not form the electrochemically active olivine-type structure, the synthesis of olivine-type NaMPO4 is a great challenge and requires original synthesis approaches. On the other hand, to improve the low rate capability of the phospho-olivines the research efforts have to be devoted to the development of new specific synthetic routes which enable to control the morphology and design M'MPO4 (M' = Li, Na) in the nano-scale region.