A hydrothermal synthesis of Ru-doped LiMn1.5Ni0.5O4 cathode materials for enhanced electrochemical performance

Dengfeng Zhou; Junqi Li; Can Chen; Fangchang Lin; Hongming Wu; Jianbing Guo

doi:10.1039/d1ra01607e

A hydrothermal synthesis of Ru-doped LiMn_1.5Ni_0.5O₄ cathode materials for enhanced electrochemical performance

RSC Adv. 2021 Mar 30;11(21):12549-12558. doi: 10.1039/d1ra01607e. eCollection 2021 Mar 29.

Authors

Dengfeng Zhou^{1

2}, Junqi Li¹, Can Chen¹, Fangchang Lin¹, Hongming Wu^{3

4}, Jianbing Guo^{1

3}

Affiliations

¹ College of Materials and Metallurgy, Guizhou University Guiyang 550025 China jqli@gzu.edu.cn jianbing.guo@126.com.
² School of Materials and Metallurgical Engineering, Guizhou Institute of Technology Guiyang 550003 China.
³ National Engineering Research Center for Compounding and Modification of Polymer Materials Guiyang 550014 China.
⁴ Guizhou Material Industrial Technology Institute, Material Technology Innovation Base of Guizhou Province Guiyang 550014 China.

Abstract

An Ru-doped spinel-structured LiNi_0.5Mn_1.5O₄ (LNMO) cathode has been prepared via a simple hydrothermal synthesis method. The as-prepared cathode is characterized via Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), laser particle size distribution analysis, X-ray photoelectron spectroscopy (XPS) and electrochemistry performance tests. The FTIR spectroscopy and XRD analyses show that the Ru-doped LNMO has a good crystallinity with a disordered Fd3̄m space group structure. The disordered structure in the cathode increased and the Li _x Ni_1-x O impurity phase decreased when Ru addition increased. SEM shows that all samples are octahedral particles with homogeneous sizes distribution, and the particle size analysis shows that the Ru-doped samples have smaller particle size. XPS confirms the existence of Ru ions in the sample, and reveals that the Ru induce to part of Mn⁴⁺ transfers to Mn³⁺ in the LNMO. The electrochemical property indicated that the Ru-doped cathode exhibits better electrochemical properties in terms of discharge capacity, cycle stability and rate performance. At a current density of 50 mA g^-1, the discharge specific capacity of the Ru-4 sample is 140 mA h g^-1, which is much higher than that of the other samples. It can be seen from the rate capacity curves that the Ru-doped samples exhibit high discharge specific capacity, particularly at high current density.