Simultaneous surface coating and chemical activation of the Li-rich solid solution lithium rechargeable cathode and its improved performance

摘要

In this study, highly dispersive spherical Li-rich solid solution (Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2) particles are successfully synthesized by a co-precipitation method. Then these particles are treated with aluminum nitrates ethanol solution at 80℃. The treatment can extract lithium (Li_2O) from the Li_2MnO_3 component in the composite of Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2. Simultaneously, a thin layer of Al_2O_3 can be precipitated on the surface of the electrode particles via direct thermal decomposition of aluminum nitrates. After treatment, the first-cycle coulombic efficiency of the electrode increases from 72.1% to 93.6%, meanwhile it shows a superior cycling stability at 100 mA g~(-1) with a discharge capacity of around 220 mAh g~(-1) and retention of 92.5% after 100 cycles, which is much higher than that of the pristine electrode (83.2%). Even at a high current density of 2 A g~(-1) (10 C), the discharge capacity could still achieve and well maintain as high as 140 mAh g~(-1).