Crystal Alignment Technology of Electrode Material for Enhancing Electrochemical Performance in Lithium Ion Battery

Abstract

The crystal alignment technology of lithium nickel manganese oxide (LiNi 0.5 Mn 0.3 Co 0.2 O 2 ) is proposed using its magnetic properties. The crystalline LiNi 0.5 Mn 0.3 Co 0.2 O 2 exhibits the paramagnetic behavior at room temperature as well as the magnetic anisotropy originated from its crystallographic anisotropy. If the crystalline LiNi 0.5 Mn 0.3 Co 0.2 O 2 is exposed to a magnetic field, it can tend to rotate to an angle minimizing its system energy due to spontaneous magnetization. Taking these magnetic natures into account, the vector quantity of an external magnetic field (i.e., magnetic flux density and field direction) is adjusted to apply to a viscous LiNi 0.5 Mn 0.3 Co 0.2 O 2 slurry coated onto a current collector; thus, the crystal aligned LiNi 0.5 Mn 0.3 Co 0.2 O 2 electrode is obtained, in which the (00 l ) plane is notably oriented perpendicular to the surface of a current collector. The aligned LiNi 0.5 Mn 0.3 Co 0.2 O 2 electrode consistently records superior electrochemical performance to a pristine LiNi 0.5 Mn 0.3 Co 0.2 O 2 electrode because the former demonstrates an improved capability of lithium ion transport during the charge/discharge process in a lithium ion battery. The aligned LiNi 0.5 Mn 0.3 Co 0.2 O 2 is considered to have the improved transport capability because the kinetics of lithium ion transport in LiNi x Mn y Co 1-( x + y ) O 2 intrinsically occurs along the (00 l ) plane.