Improving rate capability and decelerating voltage decay of Li-rich layered oxide cathodes by chromium doping

In order to improve the rate capability and mitigate the voltage decay of lithium rich layered oxides, chromium doped cathode materials Li-1.2[Mn0.54Ni0.13Co0.13](1-x)CrxO2 (x = 0,0.003,0.005,0.007) is synthesized via co-precipitation method followed by calcination. As a result, Cr-doped samples present shortened voltage platform at 4.5 V, indicating that the escape of lattice oxygen is suppressed by Cr doping. Among all samples, Li-1.2[Mn0.54Ni0.13Co0.13](1-x)CrxO2 (x = 0.005) sample shows the greatest rate capability (119.3 mAh g(-1) at 10 C) and the minimum voltage drop (0.6167 V) after 200 cycles at 1.0 C. The reasons for the improved electrochemical performance are the enhanced structural stability, the stronger Cr-O bond than Mn-O band and the decreased metal oxygen covalency induced by Cr doping. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.