Morphology Control of LiMnPO_4 Cathodes by a Careful Choice of Additives

摘要

LiMnPO_4 cathode materials of various sizes and shapes are synthesized by a hydrothermal method. In order to control the morphology of the LiMnPO_4 particles, a nonionic surfactant or a cationic surfactant has employed as a key additive to the reactant solution. LiMnPO_4 nanoparticles of grain-shape and rod-shape can be made with sizes between about 100 and 300 nm by adding a nonionic large polymer surfactant. Micrometer-sized LiMnPO_4 particles of cuboid shape result from the reaction with a cationic surfactant. LiMnPO_4 spheres of about 20 μm diameter are produced when no surfactant is added. The cathode composed of nanocrystalline (about 100 nm size) LiMnPO_4 exhibited the best performance with the specific capacity of 153 mAhg~(-1) for the first battery cycle.