Effect of AlPO₄ Nanowire Coating on the Electrochemical Properties of LiV₃O₈ Cathode Material

Abstract

In this study, AlPO 4 nanowires were coated on the surfaces of LiV 3 O 8 powders successfully. The influence of the coating on the electrochemical behavior of LiV 3 O 8 was discussed. The surface morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). AlPO 4 -coated LiV 3 O 8 cathode materials exhibited distinct surface morphology. AlPO 4 nanowires were clearly observed on the surfaces of LiV 3 O 8 . The structural changes of the cathode materials before and after coating were revealed by X-ray diffraction spectroscopy (XRD). The 1 wt % AlPO 4 coating has been found to reduce the capacity fade of LiV 3 O 8 significantly. Cyclic voltammetry (CV) shows that the characteristic phase transitions during cycling exhibited by the uncoated material are suppressed by the 1 wt % AlPO 4 coating. This behavior implies that AlPO 4 inhibits structural change of LiV 3 O 8 during cycling. In addition, the AlPO 4 coating on LiV 3 O 8 significantly suppresses the increase of charge-transfer impedance ( R ct ) in cycling. Comparative data for the coated and uncoated materials are presented and discussed.