A PVB-based rheological phase approach to nano-LiFePO₄/C composite cathodes

Nano-LiFePO₄/C cathode materials were synthesized by a PVB-based rheological phase method, followed by calcination at 550 °C for 10 h in argon. Simultaneous thermogravimetric-differential scanning calorimetry analysis indicates that the crystallization temperature of LiFePO₄ is about 436 °C. In the process of heat treatment, the decomposition of polyvinylbutyral coats carbon on the synthesized LiFePO₄ particles in situ. The resulting LiFePO₄ powders with fine particle sizes and homogeneous carbon network connection were observed by using scanning electron microscopy and transmission electron microscopy. Electrochemical measurements show that the LiFePO₄/C composite cathode delivers a large discharge capacity of 162.3 mAh·g^{- 1} at the 0.1 C rate, and exhibits a favorable capacity cycling maintenance at lower charge and discharge rate such as 0.5 C rate.