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

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 reactive-templating route to prepare manganese-based lithium-rich Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ using β−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 Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ with two integrated layered components of 0.5(Li₂MnO₃).0.5(LiMn_1/3Ni_1/3Co_1/3O₂). Electron microscopy studies reveal the formation of anisotropic rod-like crystals of 0.8–1.0 μm in length and ∼200 nm in thickness. The Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ 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 °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 °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 °C), which leads to high specific capacity, high coulombic efficiency, and high-power capability.