High-voltage electrochemical performance of LiNi0.5Co0.2Mn0.3O2 cathode material via the synergetic modification of the Zr/Ti elements

The stabilities of the host and interfacial structure for layered LiNixCoyMn1-x-yO2 cathode materials are critical for their electrochemical properties, especially at high voltage. This study reports the synergetic effect of the Zr and Ti elements on the LiNi0.5Co0.2Mn0.3O2 cathode material (NCM523). The as-obtained Zr/Ti modified LiNi0.5Co0.2Mn0.3O2 cathode material shows the excellent electrochemical performance at high voltage. It delivers 167.3 mAh·g−1 at 1 C over 3.0–4.4 V corresponding 94.20% capacity retention after 200 cycles. Moreover, the rate capability of Zr/Ti co-modified NCM523 at 16 C (3.0–4.4 V) rises to 139.4 mAh·g−1 and corresponding capacity retention (vs. 0.5 C) is 79.57%. In addition, its capacity retention reaches to 91.71% after 100 cycles at 1 C rate even at 3.0–4.6 V. Such superior electrochemical performances are ascribed to the Zr doping and Ti modification. The synergetic modifications of the Zr/Ti elements not only stabilize the crystal structure, but also absorb the lithium residues to form mixed Li4Ti5O12/Li2TiO3 coating layers, which strengthen the stability of the interfacial structure and the kinetic characteristics of the cathode materials.