Structure and cycle stability of SrHPO4-coated LiMn2O4 cathode materials for lithium-ion batteries

Abstract

The SrHPO4-coated LiMn2O4 composite materials are prepared through co-precipitation method. The phase structures and morphologies of pristine and SrHPO4 coated LiMn2O4 are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The cycling performances are thoroughly investigated and discussed both at room and elevated temperature. The results indicate that 2.0wt% SrHPO4 coated LiMn2O4 can efficiently improve the cycling performance with capacity retention of 92.3% and 83.6% under room temperature (25°C) and elevated temperature (55°C) after 100 cycles at 1C rate, respectively, which are much better than those of the pristine materials. The CV, EIS and XRF measurements reveal that the enhanced stabilization in the cycling performance can be attributed to the suppression of manganese dissolution into electrolyte with the contribution of SrHPO4 coating on the surface of LiMn2O4.