Li2ZrO3 coated LiFe0.4Mn0.6PO4/C with enhanced cycling performance at elevated temperature for lithium-ion batteries

Abstract

Lithium iron manganese phosphate (LFMP) is regarded as one of the most promising cathode materials for lithium-ion batteries due to its high energy density and low cost. However, the Jahn-Teller effect of Mn3+ inevitably causes the dissolution of Mn during the cycling process, is accompanied by a severe decrease in the discharge capacity and a decline in capacity retention rate, which is more serious at elevated temperature. Here, the LiFe0.4Mn0.6PO4/C (LFMP-0LZO) cathode material is prepared via carbothermal reduction method, and its surface is modified by Li2ZrO3 (LFMP-1LZO) to enhance the surface stability and improve the cycling performance at room temperature and elevated temperature. The residual capacities of LFMP-0LZO sample is 113.7 mAh g−1, with a capacity retention rate of only 75.55 % after 150 cycles at 55 °C and a current density of 1C (1C = 170 mA g−1), while the discharge capacity of 1 wt% Li2ZrO3-coated material (LFMP-1LZO) under the same conditions is 134.85 mAh g−1, with a higher capacity retention rate of 87.49 %. Furthermore, a series of characterization experiments show that the surface modification of LiFe0.4Mn0.6PO4/C with Li2ZrO3 can effectively inhibit the side reaction between the electrode/electrolyte interface and reduce the dissolution of Mn in the active substance.