Carbon nanocoatings on active materials for Li-ion batteries

Carbon coatings were prepared on various submicrometre-sized particles that can be used as active materials in lithium rechargeable batteries. As a precursor citrate anion was used which, after carbonization at 500-600 degrees C, transforms into a uniform, several-nanometre-thick film that is tightly adhered to the surface of substrate particles. The coatings on Li4Ti5O12 and TiO2 increased significantly the average electron conductivity of cathode composite material, which resulted in a more than 100% increase of reversible capacity at a C/3 rate. Additionally, the coating on TiO2 prevented the gradual deterioration of reversible capacity of this material observed in absence of coating. In cases where due to temperature or atmosphere sensitivity of the substrate, carbon nanocoatings cannot be prepared, we propose the use of conductive polymers. A successful wiring using a sulphonated polyaniline is demonstrated on the example of MoS2 nanotubes. (c) 2006 Elsevier Ltd. All rights reserved.