Li[Li_0.2Mn_0.54Ni_0.13Co_0.13] O₂-MoO₃ composite cathodes with low irreversible capacity loss for lithium ion batteries

To reduce the large first-cycle irreversible capacity loss of the Li-rich layered cathode material Li[Li_0.2Mn_0.54Ni _0.13Co_0.13]O₂, MoO₃ has been introduced by a simple high-energy ball milling process. The electrochemical properties of cathode material Li[Li_0.2Mn_0.54Ni _0.13Co_0.13]O₂ and the influences of different MoO₃ amount on its electrochemical properties are discussed in detail. The first charge-discharge dQ/dV curves suggest that the MoO₃ component provides additional sites for lithium ion insertion to compensate the lost Li sites caused by the simultaneous removal of Li⁺ and O ^2- during the activation of Li[Li_0.2Mn _0.54Ni_0.13Co_0.13]O₂. With increasing MoO₃ content from 0 wt.% to 20 wt.%, the first-cycle irreversible capacity loss of the composite decreases from 81.8 mAh g^-1 to 1.2 mAh g^-1. The composite with 5 wt.% MoO₃ exhibits a good cycling stability with the discharge capacity of 242.5 mAh g^-1 after 50 cycles, and the thickness of the MoO₃ coating layer on the surface of Li[Li_0.2Mn_0.54Ni_0.13Co_0.13] O₂ is about 3-4 nm. However, with the increase of the addition content of MoO₃, the cycling stability of the Li[Li _0.2Mn_0.54Ni_0.13Co_0.13]O ₂-MoO₃ composite is decreased.