Improving electrochemical performances of Lithium-rich oxide by cooperatively doping Cr and coating Li3PO4 as cathode material for Lithium-ion batteries.

We prepared the Cr-doped Li-rich cathodes coated by Li 3 PO 4 with stable capacity and median voltage for lithium-ion batteries. Lithium-rich layered oxides exhibit one of the highest reversible discharge capacities among cathode materials for lithium-ion batteries. However, their voltage decay and poor cycle stability severely restrict their use as a commercial cathode material. In this work, a novel approach of that combines Cr doping and a Li 3 PO 4 coating was designed to address the problems associated with lithium-rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 materials. The synergistic method not only increases the discharge capacity and cycle stability but also decreases the voltage decay. The 1.0 wt% Li 3 PO 4 coating and 0.08 Cr doping on Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode shows a capacity retention of 76.5% compared to the 59.0% capacity retention for the pristine electrode after 200 cycles. The initial discharge capacity is also increased from 255.8 mAh·g−1 to 265.2 mAh·g−1. In addition, the discharge voltage decay decreases from 0.84 V to 0.39 V after 200 cycles as a result of the Cr doping and Li 3 PO 4 coating. These enhanced electrochemical properties are attributed to the fact that the Cr doping stabilized the layered structure and inhibited its phase transformation to the spinel phase, and the Li 3 PO 4 coating confined the interfacial side reactions between the electrode and electrolyte. This work may provide a new method to solve the subsistent problems of lithium-rich cathode materials. [ABSTRACT FROM AUTHOR]