Reactive template synthesis of Li1.2Mn0.54Ni0.13Co0.13O2 nanorod cathode for Li-ion batteries: Influence of temperature over structural and electrochemical properties

摘要

Common preparation methods of manganese-based Li-rich layered oxides include co-precipitation, combustion, spray pyrolysis, and molten salt synthesis. Herein, we present a facile new reactivetemplating route to prepare manganese-based lithium-rich Li1.2Mn0.54Ni0.13Co0.13O2 using beta-MnO2 nanorod, which plays a dual role as reactive template as well as Mn-source. Rietveld refinement and electron diffraction patterns confirm the formation of phase pure, highly crystalline Li1.2Mn0.54Ni0.13Co0.13O2 with two integrated layered components of 0.5(Li2MnO3).(0.5)(LiMn1/3Ni1/3Co1/3O2). Electron microscopy studies reveal the formation of anisotropic rod-like crystals of 0.8-1.0 mm in length and similar to 200 nm in thickness. The Li1.2Mn0.54Ni0.13Co0.13O2 nanorod as cathode for Li-ion battery, delivers an impressive reversible capacity of 223 mAh.g(-1) at 0.1C rate after 150 cycles and 161 mAh.g(-1) at 1 C rate after 300 cycles. Rapid structural transition from layered to spinel-like phase at high temperature (55 degrees C) leads to gradual decay in discharge capacity upon cycling, whereas low Li-ion diffusivity, cell resistance, and high viscosity hampers the performance at low temperature (5 degrees C). Impedance spectroscopy along with (dis) charge differential plots corroborate that activation of Li2MnO3 and Li-ion de(intercalation) into the MnO2 phase is very facile at high temperature (55 degrees C), which leads to high specific capacity, high coulombic efficiency, and high-power capability. (C) 2019 Elsevier Ltd. All rights reserved.