Effects of surface area on electrochemical performance of Li[Ni0.2Li0.2Mn0.6]O2 cathode material

The effect of surface area on the electrochemical properties and thermal stability of Li[Ni0.2Li0.2Mn0.6]O-2 powders was characterized using a charge/discharge cycler and DSC ( Differential Scanning Calorimeter). The surface area of the samples was successfully controlled from similar to 4.0 to similar to 11.7 m(2) g(-1) by changing the molar ratio of the nitrate/acetate sources and adding an organic solvent such as acetic acid or glucose. The discharge capacity and rate capability was almost linearly increased with increase in surface area of the sample powder. A sample with a large surface area of 9.6-11.7 m(2) g(-1) delivered a high discharge capacity of similar to 250 mAh g(-1) at a 0.2 C rate and maintained 62-63% of its capacity at a 6 C rate versus a 0.2 C rate. According to the DSC analysis, heat generation by thermal reaction between the charged electrode and electrolyte was not critically dependent on the surface area. Instead, it was closely related to the type of organic solvent employed in the fabrication process of the powder.