Synthesis of nanoarchitectured LiNi0.5Mn0.5O2 spheres for high-performance rechargeable lithium-ion batteries via an in situ conversion route

Abstract

LiNi_0.5Mn_0.5O₂ nanoarchitectured spheres (NA-LiNi_0.5Mn_0.5O₂) have been synthesized via an in situ conversion route derived from the use of γ-MnO₂ hollow nanostructured spheres. The complete conversion of the γ-MnO₂ precursor to layered α-NaFeO₂-type NA-LiNi_0.5Mn_0.5O₂ has been confirmed by XRD, FE-SEM, TEM, and HR-TEM. This NA-LiNi_0.5Mn_0.5O₂ cathode exhibits a remarkable enhancement of rate performance compared with that of LiNi_0.5Mn_0.5O₂ particles prepared by a conventional solid-state reaction method (SS-LiNi_0.5Mn_0.5O₂). The batteries based on NA-LiNi_0.5Mn_0.5O₂ retain a discharge capacity of 153.5 mA h g⁻¹ (93% of the first discharge capacity) after 75 cycles. A specific discharge capacity of 121.9 mA h g⁻¹ was retained at a rate of 3.2 C, which is about 70% of the capacity at a rate of 0.2 C.