A novel morphology of high voltage LiMn1.5Ni0.5O4 cathode material with niobium-doping

Abstract

Spinel LiMn1.5Ni0.5O4 (LMNO) is one of the promising cathode materials for the next generation Li-ion batteries due to its voltage platform. However, the dissolution of the transition metal at high voltage is the biggest obstacle that LMNO suffers from. In this study, we successfully suppressed transition metal dissolution in LMNO by the morphology control from regular octahedron to spherical. Niobium was integrated as a dopant, which restricted the growth of (111) crystal face, and increased the indices of crystal faces by homogenizing the surface energy. By changing to a smaller surface area with spherical morphology, the contact area with the electrolyte was reduced, thus suppressing the dissolution of the Mn ion. Consequently, the niobium-doped LMNOexhibited superior rate performance, capacity retention with 74.1% at 1C after 500 cycles in half-cell, and thermal stability compared to pristine LMNO.