Long-Term Cyclability of Nano-Crystalline LiFePO4
In the previous chapter we described the preparation of nano-crystalline LiFePO4 by heating amorphous nano-sized LiFePO4 (Prosini et al., J. Electrochem. Soc. 149:A886–A890, 2002). The crystalline phase was obtained after heating the amorphous compound in a tubular furnace at 550°C for 1 h under reducing atmosphere (Ar/H2). In this chapter, we further report on the electrochemical characterization of crystalline LiFePO4 obtained by firing the amorphous precursor at 550°C for different periods of time (Prosini et al., Electrochim. Acta 48:4205–4211, 2003). All the samples showed very good electrochemical performance in terms of energy and power density. Upon cycling a capacity fading affected the material, thus reducing the electrochemical performance. The initial fading was related to structural variations or contact losses between the conductive binder and the active material particles, resulting from volume variations during lithium extraction. The fading decreased upon cycling and after the 200th cycle the material was able to intercalate/deintercalate lithium for more than 500 cycles without further capacity decline.
KeywordsSpecific Capacity Electrochemical Performance Firing Time Good Electrochemical Performance Amorphous Precursor