One-time sintering process to synthesize ZrO-coated LiMnO materials for lithium-ion batteries.

Herein, different amounts of ZrO-coated LiMnO materials are successfully prepared by one-time sintering ZrO-coated MnO and LiCO. Scanning and transmission electron microscopy results confirm that the ZrO coating layer on the surface of MnO can still be maintained on the surface of the final LiMnO particles even after long-term high-temperature heat-treatment. Three key factors to realize ZrO-coated LiMnO materials the one-time sintering process are as follows: (i) the MnO precursor is coated by ZrO in advance; (ii) the ionic radius of Zr is much larger than those of Mn and Mn; (iii) the pre-calcination temperature is set in the reaction temperature range between LiCO and MnO and lower than that between LiCO and ZrO. The 3 wt% ZrO-coated LiMnO material exhibits excellent electrochemical properties with an initial specific discharge capacity of 118.8 mA h g and the capacity retention of 90.1% after 400 cycles at 25 °C and 88.9% after 150 cycles at 55 °C. Compared with the conventional coating method, the one-time sintering process to synthesize ZrO-coated LiMnO materials is very simple, low-cost, environmentally friendly, and easy to scale up for large-scale industrial production, which also provides a valuable reference for preparing other coating-type cathode materials for lithium-ion batteries.