Atomic Insights into Ti Doping on the Stability Enhancement of Truncated Octahedron LiMn2O4 Nanoparticles

Abstract

Ti-doped truncated octahedron LiTixMn2-xO4 nanocomposites were synthesized through a facile hydrothermal treatment and calcination process. By using spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), the effects of Ti-doping on the structure evolution and stability enhancement of LiMn2O4 are revealed. It is found that truncated octahedrons are easily formed in Ti doping LiMn2O4 material. Structural characterizations reveal that most of the Ti4+ ions are composed into the spinel to form a more stable spinel LiTixMn2−xO4 phase framework in bulk. However, a portion of Ti4+ ions occupy 8a sites around the {001} plane surface to form a new TiMn2O4-like structure. The combination of LiTixMn2−xO4 frameworks in bulk and the TiMn2O4-like structure at the surface may enhance the stability of the spinel LiMn2O4. Our findings demonstrate the critical role of Ti doping in the surface chemical and structural evolution of LiMn2O4 and may guide the design principle for viable electrode materials.

Understanding the Effect of Al Doping on the Electrochemical Performance Improvement of the LiMn2O4 Cathode Material

“…The LiAl x Mn 2– x O 4 (0 ≤ x ≤ 0.2) cathode materials were prepared by the method reported in our previous works with Al­(NO 3 ) 3 ·9H 2 O (99.0%, Aladdin Chemical Reagent Co., Ltd.) being added as one more reactant. , To get Al-doped LiMn 2 O 4 precursors, after mixing Al­(NO 3 ) 3 ·9H 2 O with the other reactants, the powders were burned in a muffle furnace at 500 °C for 3 h. The final products were obtained by the as-prepared Al-doped LiMn 2 O 4 precursors calcined in a muffle furnace at 750 °C for 6 h.…”

“…To solve the above problems, partial replacement of Mn 3+ through chemical doping was used to increase the average oxidation state of Mn (higher than 3.5), which will well restrain the structural deformation caused by Jahn–Teller distortion and hence improve the cyclic performance of LiMn 2 O 4 . , Several transition-metal (TM) elements are proved to be effective for doping, such as Ni, Al, Cr, Mg, Cu, and so on. Among the above elements, Al has been reported to be one of the most favorable elements as it is nontoxic, abundant, less expensive, and lighter than other TM elements. − Also, the chemical bond of Al–O (512 kJ mol –1 ) is stronger than that of Mn–O (402 kJ mol –1 ), so Al substitution will lead to the lattice parameter decrease and further increase the stability of octahedral sites by inhibiting the Jahn–Teller distortion .…”

Modulation of Ferroelectric and Optical Properties of La/Co-Doped KNbO3 Ceramics

“…In the past several decades, ferroelectric materials have become important candidates for photovoltaic, random-access memory and optoelectronic devices due to their inherent spontaneous polarization [ 1 , 2 , 3 , 4 , 5 , 6 ]. Among them, KNbO 3 (KNO) materials with excellent properties are a research hotspot.…”

One pot synthesis of hydrogen and glucaric acid via glucose electrolysis

“…1e). 55–57 Moreover, an additional satellite peak was observed at 662.2 eV. Also, O1s spectra upon fitting showed the presence of M–O binding at 530.9 eV which might be due to the formation of nickel and manganese oxides.…”