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Abstract: Cathodes in lithium ion batteries consist of an ionic conductor, an electronic conductor and a binder in order to make a composite that is both electronically and ionically conductive. The carbon coating on the cathode material plays a critical role for the electrochemical properties of lithium ion batteries due to the increased electronic conductivity. We explain the relationship between the electrochemical properties and the characteristics of composites prepared using the ball-milling process in this report. We investigated two types of carbonaceous materials (graphite and carbon black) in LiCoO2 electrodes. These selected carbon materials have different characteristics and structure upon ball-milling with LiCoO2. The composite prepared by ball-milling for 5min leads to better mixing of carbon and LiCoO2, an intimate contact of carbon on LiCoO2, a higher lithium ion diffusion (DLi) than non ball-milled and longer ball-milled composites. On the other hand, a longer time of ball-milling (30 and 60min) decreases the electronic and ionic conductivity due to an increase of disordered structure of carbon and a thick and dense carbon coating layer on LiCoO2 particles, preventing the diffusion of lithium ions, respectively. [Copyright &y& Elsevier]

Abstract: 5–10nm thin rod shaped LiMnPO4 nanoparticles are synthesized by an improved thermal decomposition method. The synthesis parameters such as the concentration of surfactants, reaction temperature and time, as well as the presence of a solvent play a critical role in the formation of spherical, thin or thick nanorods, and needle-shaped particles of LiMnPO4. A washing procedure to efficiently eliminate the surfactants attached to the surface of LiMnPO4 nanoparticles is presented, avoiding thermal treatment at high temperatures. A nanocomposite LiMnPO4 electrode provides a discharge capacity of 165mAh/g at 1/40C and 66mAh/g at 1C with only 10wt% of total carbon additive. The characteristics of as-synthesized and low amount of carbon coated LiMnPO4 are described as well as their electrochemical properties. [Copyright &y& Elsevier]