Improved electrochemical properties of LiNi0.8Co0.15Al0.05O2 cathode materials synthesized using micelle structures

Abstract

Although LiNi0.8Co0.15Al0.05O2 (NCA) has various merits such as a high discharge capacity of ~ 195 mAh g−1, improved stability, and low cost, intergranular cracks in the NCA structure can suppress the electronic/ionic motion in the cathode. Thus, in this study, to minimize crack portions in the NCA cathode, we synthesized dense NCA cathode materials using micelle structures controlled with pluronic acid (F127) and polyvinyl alcohol (PVA) as polymer templates and evaluated the electrochemical performance in LIBs using coin-type cells. We found that all the as-prepared samples showed the LiNiO2-based structures doped with Co and Al. With an increasing amount of PVA, the 1st particles can be more agglomerated during heating and thus increase the size of the 2nd particles. Consequently, a significantly dense NCA structure consisting of less cracked 2nd particles can be prepared in the presence of F127 and PVA. In particular, the NCA cathode prepared with an optimal ratio of F127 to PVA exhibited the best electrochemical properties, i.e., high capacity and superior cycle life.