Electrochemical effects and magnetic properties of B substituted LiCoO₂: Improving Li-battery performance

LiCo_1-xB_xO₂ (x = 0, 0.125, 0.25, 0.375, 0.5, 0.75 and 1) samples were synthesized via solid state reactions. They were characterized by SEM, X-ray powder diffraction, FTIR, Raman, electrical and magnetic measurements. XRD data show impurity phases for x ≥ 0.25 samples due to boron content. Based on FTIR studies, the peak position of CoO₆ shifts with increasing B content. The Raman spectra of LiCoO₂ shows the presence of three broad bands, indicating the possible formation of spinel structure. The effective magnetic moments of the samples were calculated using Curie-Weiss law with temperature independent term. The M-H curves of x = 0.375 and 0.5 samples show very weak hysteresis loops. Effects of boron substitution on battery performance are also investigated. x = 0.125 and x = 0.25 samples give promising results due to their enhanced reversibility of cycling compared to pristine LiCoO₂. Capacity retentions for 100 cycles for x = 0, 0.125 and 0.25 samples are 22%, 81% and 83%, respectively.