Effect of lithium powder size on the performance of lithium-powder/lithium trivanadate secondary batteries shown via impedance analysis

Abstract

Effect of powder size on the performance of Li-powder/LiV3O8 secondary cell has been studied. Li powder, synthesized via droplet emulsion technique, was used as the anode material in a coin cell (CR 2032) assembled in an Ar-filled glove box. Discharge-charge cycling was galvanostatically performed at 0.2 C-rate with cut-off voltages of 1.5-4.0V. Li powder with smaller particle size shows better cycling performance. The electrochemical properties (capacity versus cycle number, impedance) of the fabricated coin cells were evaluated. Based on the linear sweep voltammetry data, it was concluded that electrode with 15-mu m powder size has larger surface area than electrodes with 35- and 55- mu m powder size. Moreover, these electrodes produced larger current than that produced by Li foil electrode. The anode having 15-mu m powder size had 12-fold larger surface area than the Li foil anode; its surface area was also larger than that of the Li powder anodes with larger particles. The superior cycle stability of this anode was because of its larger surface area. (C) 2014 Elsevier Ltd. All rights reserved.