Effect of structural integration on electrochemical properties of 0.5Li₂MnO₃-0.5Li(Mn_0.375Ni _0.375Co_0.25)O₂ composite cathodes for lithium rechargeable batteries

In the present work, we have investigated the effect of the structural integration between Li₂MnO₃ and Li(Mn _0.375Ni_0.375Co_0.25)O₂ components on the electrochemical properties of the resultant compounds. We have adopted three processing methodologies to attain the structural integration of Li ₂MnO₃ component in Li(Mn_0.375Ni _0.375Co_0.025)O₂ layered cathode. The best electrochemical properties are achieved in the composites where Li ₂MnO₃ type nano-domains were formed in situ in Li(Mn _0.375Ni_0.375Co_0.25)O₂ particles. For these composites the 1^st cycle discharge capacity (at 10 mAg ^-1 rate) was measured to be 300 mAhg^-1 with a capacity retention ∼220 mAhg^-1 after 50 cycles. These cathodes exhibit decent rate capability with typical discharge capacity ∼120 mAhg ^-1 at 300 mAg^-1 rate. One of the remarkable finding of the present work is to demonstrate that in order to yield attractive electrochemical performance of such integrated cathode; structural integration between the Li₂MnO₃ and Li(Mn_0.375Ni _0.375Co_0.25)O₂ is essential. To achieve better structural integrity in the physically mixed composites, finer particle size of the individual (Li₂MnO₃ and Li(Mn_0.375Ni _0.375Co_0.25)O₂) components, through intermixing between them, and optimization of calcinations temperature and time are recommended.