Crystalline geometry engineering towards high-energy spinel cathode for lithium-ion batteries

Abstract

The spinel LiNi0.5Mn1.5O4 (LNMO) material is considered as a promising cathode in high-voltage lithium-ion batteries due to its advantageous voltage and capacity. Previous results indicate that the electrodes constructed by LNMO with the same compositions while differing in the crystallite geometries always exhibit various electrochemical performances. Here, to probe the relationships between the crystalline geometry of the obtained cathodes and their electrochemical properties, we synthesized different facet-exposed LNMOs with the same compositions using a template method. We demonstrate that the crystallite geometries of the hydroxide precursors can be tuned easily via varying the synthesize parameters, while the tuned precursors can be employed as the templates during the final product preparation. LNMOs enclosed by single {111} facets (LNMO-OH) and both {110} and {100} facets (LNMO-HP) are obtained and employed to elucidate the particle geometry-dependent electrochemical properties. Despite better rate capabilities exhibited for LNMO-HP because of the higher lithium diffusion coefficients along these crystal orientations, inferior cycling performance is released compared with its LNMO-OH counterpart. These insights can provide informative guidance in particle geometry-dependent material construction, thus helpful in realizing high-performance LNMO cathode.