Zr-containing phosphate coating to enhance the electrochemical performances of Li-rich layer-structured Li[Li0.2Ni0.17Co0.07Mn0.56]O2

Abstract

The continuous phase transformation from the layered structure to the spinel-like phase seriously degrades the electrochemical properties of Li-rich layered oxides in Lithium-ion batteries. Herein, heterostructured Li-rich cathode materials Li[Li0.2Ni0.17Co0.07Mn0.56]O2 in conjunction with different contents of Zr-containing phosphate (ZCP) coating layers were prepared. The structural and electrochemical characterizations reveal that the ZCP surface layer, which not only prevents electrolyte from eroding the Li-rich core and thus suppressing the fast growth of solid electrolyte interface film and charge transfer resistance on the surface of oxide particles, but also enhances the structural and thermal stabilities of the electrode. As a result, the 3wt.% coated sample delivers an initial discharge capacity of 216mAhg⿿1 with a coulombic efficiency of 80%, compared to 202mAhg⿿1 and 71%, respectively, for the bare sample. Particularly, the coated sample demonstrates excellent cycling stability with a capacity retention of 91% within 100 cycles, and higher thermal stability.