Enhanced rate and low-temperature performance of LiFePO4 cathode with 2D Ti3C2 MXene as conductive network

In recent years, LiFePO4 (LFP) has been widely used as the cathode of lithium-ion batteries due to its excellent stability, safety, and low cost. However, the low electronic conductivity limits its applications at low temper-ature or in high power occasions. Herein, we fabricated a network with excellent electrical conductivity using two-dimensional MXene to improve the poor conductivity of the LFP cathode. Benefited from the hydrophilic-ity of MXene, LFP and MXene were evenly dispersed in the water by ultrasonic treatment and freeze-dried to obtain LiFePO4/MXene (LFP/MXene) powder. Then, Ketjen black (KB) was mixed into the electrode slurry to prevent the restacking of 2D MXene and form a "surface-chain" conductive network structure. The prepared LFP/MXene/KB electrode exhibits an excellent rate performance (-120 mAh g-1 even at 10 C-rate) at room temperature. Combined with the electrolyte with low de-solvation energy using 1,3-dioxolane as the solvent, the LFP/MXene/KB electrode displays a good low-temperature tolerant performance. Only a weak IR drop can be detected, and about 133 mAh g-1 discharge capacity can be maintained at -40 degrees C and 0.1 C-rate. Both of these provide a practical guidance for the design of LFP with outstanding rate and low-temperature performances.