Electrochemical Properties of LiFePO4 Cathodes: The Effect of Carbon Additives
The influence of different conductive additives (carbon nanofibers (CNFs), carbonnanoplatelets, and pyrolytic carbon from sucrose (Sucr) or polyvinylidene fluoride) on the morphology, electron conductivity, and electrochemical performance of LiFePO4-based cathodes wasinvestigated to develop the most efficient strategy for the fabrication of high-rate cathodes. Pyrolyticcarbon effectively prevents the growth of LiFePO4 grains and provides contact between them, CNFsprovide fast long-range conductive pathways, while carbon nanoplatelets can be embedded in carboncoatings as high-conductive “points” which enhance the rate capability and decrease the capacityfading of LFP. The LiFePO4/CSucr/CNF showed better performance than the other cathodes due tothe synergy of the high-conductive CNF network (the electronic conductivity was 1.3 × 10−2 S/cm)and the shorter Li+ion path (the lithium-ion diffusion coefficient was 2.1 × 10−11 cm2/s). It is shownthat the formation of composites based on LFP and carbon nanomaterials via mortar grinding is amore promising strategy for electrode material manufacturing than ball milling.