Constructing hierarchical urchin-like LiNi0.5Mn1.5O4 hollow spheres with exposed {111} facets as advanced cathode material for lithium-ion batteries

Abstract

Control over porosity and crystal orientation is a huge challenge in the field of materials science. Cathode materials with high porosity and reactivity of exposed crystal planes contribute to the charge transfer kinetics, structural stability and interfacial compatibility between electrode and electrolyte. In this paper, hierarchically porous urchin-like LiNi0.5Mn1.5O4 hollow spheres comprising aggregated nanosheets with highly exposed {111} facets have been successfully synthesized with ultrathin MnO2 nanosheets encapsulating poly styrene spheres as precursor. Transmission electron microscopy results present the crystal orientation of target cathode material is exposed with dominant {111} facets, which could effectively relieve the dissolution of manganese from the lattice, thus leading to an excellent cycling stability. The charge-discharge characterizations demonstrate that the resultant urchin-like LiNi0.5Mn1.5O4 hollow spheres exhibits excellent rate capability and high-rate cyclic stability. Notably, even at a high rate of 30 C, the battery can deliver about 92% of the initial discharge capacity retention after 1500 cycles. Experiment results and theoretical calculation indicate that the superior performance of the synthesized product can be ascribed to its intrinsic structure and preferred orientation growth of {111} facets. Therefore, hierarchically porous urchin-like LiNi0.5Mn1.5O4 with highly exposed {111} plane is a promising cathode material for high-energy density lithium-ion batteries.