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

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.