Enhanced Electrochemical Performance of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Cathode Material by Ultrathin ZrO 2 Coating

Ultrathin ZrO2 coatings are successfully adopted to modify the surface of the layered LiNi0.5Co0.2Mn0.3O2 cathode material via atomic layer deposition (ALD) technology. Compared with the bare LiNi0.5Co0.2Mn0.3O2, the ultrathin ZrO2-coated cathode materials exhibited a significantly improved discharge capacity and cycleability. Among all of the samples, ZrO2-coated LiNi0.5Co0.2Mn0.3O2 electrode with 5 ALD layers showed highest initial Coulombic efficiency, excellently electrochemical cycleability and high rate capability in the voltage range of 2.5-4.5 V at room temperature. Furthermore, this sample showed a discharge capacity of 155.1 mAh g(-1) with a high retention of 88.1% at the current of 1000 mA g(-1) (5C) after 60 cycles at the elevated temperature of 55 degrees C, which demonstrated a remarkable enhancement about 150% over that of the bare one. Such enhanced electrochemical performance can be attributed to the high-quality ultrathin ALD metal oxide coating for the cathode material, which protects the cathode material from the undesirable side reaction with the electrode and suppresses the increasing impedance in order to facilitate the diffusion of lithium ion into the host oxide. (C) 2015 Elsevier B.V. All rights reserved.