High Volumetric Energy Density LiFePO4/C Cathode Materials Synthesized by Dodecyl Polyglucoside-Assisted Glucose-Polyethylene Glycol Composite Carbon Source

Abstract

Abstract High volumetric energy density LiFePO4/C cathode materials were synthesized by wet ball milling, spray drying, and carbothermal reduction method using glucose and polyethylene glycol (PEG) as composite carbon sources and dodecyl polyglucoside (C12APG) as a milling aid. With the introduction of C12APG during the ball milling process, the prepared cathode materials have uniform particle size (100-200 nm in diameter) and regular primary particle morphology. In addition, PEG substitutes part of glucose as a carbon source, resulting in low carbon content and high graphitization of residual carbon after high-temperature calcination. The prepared LiFePO4/C cathode materials have a high powder compaction density (2.68 g cm-3) and excellent electrochemical performance (discharged capacities of 161.2 and 141.7 mAh g-1 at 0.2 C and 5 C, and cycle retention of 98.6% for 100 cycles at 1 C/1 C). This LiFePO4/C composite was assembled into 14500-type cylindrical batteries with a compaction density of 2.62 g cm-3 for the positive electrode. The volumetric energy densities of the positive electrode were 1135.18 Wh L-1 and 918.16 Wh L-1 at 0.2 C and 5 C, respectively.