Electrochemical properties of 0.6Li₂MnO₃ · 0.4Li(Ni_0.8Co_0.15Al_0.05)O₂ composite nanopowders prepared by spray pyrolysis

Nano-sized composite cathode powders [0.6Li₂MnO₃. 0.4Li(Ni_0.8Co_0.15Al_0.05)O₂] are prepared by a scalable spray pyrolysis process. The addition of an organic additive into the spray solution is a key factor for the large production of nano-sized composite cathode powders. After post-treatment at high temperatures and a simple milling process, the composite powders prepared from a spray solution with citric acid and ethylene glycol are the size of nanometers. Mean sizes of the powders after post-treatment at 600 and 900°C are 20 and 200 nm, respectively. An ICP analysis determined that the mole ratio of Li/(Ni + Mn + Co) in the powders post-treated at 900°C, is 1.3. The initial charge capacities of the powders post-treated at 600, 700, 800, and 900oC are 357, 341, 338, and 294 mAh g^-1. Their initial discharge capacities are 218, 233, 231, and 240 mAh g^-1. The composite powders post-treated at 900°C have the highest Coulombic efficiency. The discharge capacity of the composite powders post-treated at 900oC decreases from 240 to 229 mAh g^-1 by the 30^th cycles, in which the capacity retention is 95.4%.