Nanostructured LiMPO₄(M = Fe, Mn, Co, Ni) – carbon composites as cathode materials for Li-ion battery

Abstract

Abstract. Nanostructured materials are considered to be strong candidates for fundamental advances in efficient storage and/or conversion. In nanostructured materials transport kinetics and surface processes play determining roles. This work describes recent developments in the synthesis and characterization of composites which consist of lithium metal phosphates (LiMPO 4 , M = Fe, Mn, Co, Ni) coated on nanostructured carbon supports (unordered nanofibers, foams). The composites have been prepared by coating the carbon structures in aqueous (or polyols) solutions containing lithium, metal ions and phosphates. After drying out, the composites have been thermally treated at different temperatures (between 600-780°C) for 5-12 hours under nitrogen. The formation of the olivine structured phase was confirmed by the X-ray diffraction analysis on powders prepared under very similar conditions. The surface investigation revealed the formation of an homogeneous coating of the olivine phase on the carbon structures. The electrochemical performance on the composites showed a dramatic improvement of the discharge specific capacity (measured at a discharge rate of C/25 and room temperature) compared to the prepared powders. The delivered values were 105 mAhg -1 for M = Fe, 100 mAhg -1 for M = Co, 70 mAhg -1 for M = Mn and 30 mAhg -1 for M = Ni respectively.

Electrospinning: How to Produce Nanofibers Using Most Inexpensive Technique? An Insight into the Real Challenges of Electrospinning Such Nanofibers and Its Application Areas

“…According to the report of Dimesso et al the cathode material of Li-ion batteries can be successfully prepared using the 3-D structures of LiFePO4 coated nanofiber nonwovens 44 . Such uniformly distributed LiFePO4 crystallites over the surface area of carbon nonwoven fibers exhibited good performances delivering a discharge capacity of 156 & 152 mAh/g at discharge rates of c/25 & c/10 at room temperature, respectively.…”