Excellent cycling stability of spherical spinel LiMnO by YO coating for lithium-ion batteries.

The YO nano-film is coated on the surface of the spherical spinel LiMnO by precipitation method and subsequent heat treatment at 550 °C for 5 h in air. The structure and performance of the bare LiMnO and YO-coated LiMnO are characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis X-ray spectroscopy, galvanostatic charge-discharge, cyclic voltammetry, and impedance spectroscopy. It has been found that the addition of YO does not change the bulk structure of LiMnO, and the thickness of the YO coating layer is approximate to 3.0 nm. The 1 wt% YO-coated LiMnO electrode reveals excellent cycling performance with 80.3 % capacity retention after 500 cycles at 1 C at 25 °C. When cycling at elevated temperature 55 °C, the as-prepared sample still shows 76.7 % capacity retention after 500 cycles. These remarkable improvements indicate that thin YO coating on the surface of LiMnO is an effective way to improve the electrochemistry performance. Besides, the suppression of Mn dissolution into the electrolyte via the YO coating layer can be accounted for the improved performances. [ABSTRACT FROM AUTHOR]