Facile synthesis of LiMn₂O₄ octahedral nanoparticles as cathode materials for high capacity lithium ion batteries with long cycle life

Spinel lithium manganate octahedral nanoparticles have been prepared by high temperature solid-state combustion reaction using cellulose as fuel. The crystal structure, morphology, and electrochemical performance of the as-prepared materials are analyzed by X-ray diffraction (XRD), electron microscopy, and electrochemical testing. The XRD results show that the materials are single-phase and perfectly crystalline with a spinel structure. Microscopic observations reveal that the nanoparticles possess octahedral morphology, with an average particle size of about 165.4 nm and a uniform particle size distribution. The lithium manganate octahedral nanoparticles exhibit excellent initial discharge capacity of 118.5 and 78.3 mAh g^-1, and about 72.49% and 94.6% of its initial discharge capacity can be retained even after 1600 cycles at 10 C and 3000 cycles at 20 C, respectively. The excellent electrochemical performance of the lithium manganate can be mainly attributed to the strong MnO₆ framework mitigates the occurrence of Mn dissolution, maintains structural stability, and allows higher Li⁺ diffusion during electrochemical cycling. Furthermore, the nano-sized octahedral structure not only facilitates fast ion diffusion, but also mitigates the manganese dissolution due to the exposed (111) crystal planes, where the solid electrolyte interphase (SEI) forms. © 2014 Elsevier B.V. All rights reserved.