Mitigating the Surface Degradation and Voltage Decay of LiNiMnCoO Cathode Material through Surface Modification Using LiZrO.

In the quest to tackle the issue of surface degradation and voltage decay associated with Li-rich phases, Li-ion conductive LiZrO (LZO) is coated on LiNiMnCoO (LNMC) by a simple wet chemical process. The LZO phase coated on LNMC, with a thickness of about 10 nm, provides a structural integrity and facilitates the ion pathways throughout the charge-discharge process, which results in significant improvement of the electrochemical performances. The surface-modified cathode material exhibits a reversible capacity of 225 mA h g (at C/5 rate) and retains 85% of the initial capacity after 100 cycles. Whereas, the uncoated pristine sample shows a capacity of 234 mA h g and retains only 57% of the initial capacity under identical conditions. Electrochemical impedance spectroscopy reveals that the LZO coating plays a vital role in stabilizing the interface between the electrode and electrolyte during cycling; thus, it alleviates material degradation and voltage fading and ameliorates the electrochemical performance.