Titanium dioxide and carbon co-modified lithium manganese silicate cathode materials with improved electrochemical performance for lithium ion batteries

Synthesis and Characterization of Li2Mn0.8Ni0.2SiO4/Mn3O4 Nanocomposite for Photocatalytic Degradation of Reactive Blue (RB5) Dye

This study successfully synthesized Li2MnSiO4/Mn3O4 (LMS/M3) and Li2Mn0.8Ni0.2SiO4/Mn3O4 (LMNS/M3) nanocomposites in a two-step method first, by preparing Mn3O4 (M3) nanoparticles through a hydrothermal method and second, by synthesizing Li2MnSiO4 (LMS) and Li2Mn0.8Ni0.2SiO4 (LMNS) by ethylene diamine tetra-acetic assisted sol–gel method. In the last method, the two nanoparticles are mixed by hand-milling to form nanocomposites. Synthesized nanoparticles were characterized using X-ray diffraction, Fourier-transform infrared, Raman spectra, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area, pL and UV–vis spectra measurements. The nanocomposite presents a well-developed orthorhombic crystal structure with a Pmn21 space group. BET surface area measurements indicate that all the prepared materials are mesoporous. The photocatalytic activity of M3, LMS, LMNS, (LMS/M3), and (LMNS/M3) was investigated by the photocatalytic degradation of reactive blue 5 (RB5) under UV light irradiation using a homemade photoreactor. The maximum photodegradation was achieved at optimal pH 4 and photocatalyst dose 0.005 g/50 ml dye. Higher stability for dye degradation efficiency was attained for the LMS and LMNS nanomaterials and LMS/M3 and LMNS/M3 nanocomposites than M3 to photocatalytic activity. The photocatalyst is readily recoverable and shows excellent stability even after three cycles. The photocatalytic degradation for RB5 followed first-order kinetics.

Graphical Abstract

Improved cycling performance and rate stability of ITO-compounded Li2MnSiO4 for lithium-ion batteries

Li₂MnSiO₄ compounded with indium tin oxide (ITO) was successfully synthesized through a sol-gel method. The structure and morphology characterization of Li₂MnSiO₄/ITO nanocomposite are demonstrated by XRD, SEM, TEM, EDS and XPS. Galvanostatic charge-discharge tests, EIS and CV are employed to examine the electrochemical performance of the composite. From those results, it could be observed that the electrochemical performance of Li₂MnSiO₄ cathode material has been significantly improved due to the introducing of indium tin oxide. The 3 wt% ITO-compounded sample displayed a discharge specific capacity around 141 mA h g^-1 at 0.05C, 134.4 mA h g^-1 at 0.1C, 132.9 mA h g^-1 at 0.2C and 127.4 mA h g^-1 at 0.5C in the first cycle, which is much higher than the pristine sample.

Effect of Ni substitution on structural stability, micromorphology, and electrochemical performance of Li2MnSiO4/C cathode materials

Li₂Mn_1−xNi_xSiO₄/C samples doped with different amounts of Ni show improved performances, especially the optimal capacity appears in the 5.0% Ni sample.