Improved high-voltage performance of LiNi0.87Co0.1Al0.03O2 by Li+-conductor coating

Abstract

Ni-rich layered oxide cathode material is extensively studied as promising cathode material in high-energy lithium ion batteries. However, capacity decay, poor rate performance and thermal instability are critical challenges for commercialization. Herein, Ni-rich layered oxide cathode material (LiNi0.87Co0.1Al0.03O2) is synthesized via oxide precursor and further modified by amorphous Li+-ion conductor Li2O-BPO4 (LBP) coating. The LBP coating layer can facilitate the transfer of Li+ across the solid-electrolyte interface, reduce the side reaction between the cathode-and electrolyte as well as decrease cation mixing. Therefore, the NCA coated by LBP displays the improved cycling performance due to the increased interfacial stability, the decreased polarization and the intensified Li+ transport kinetics. Especially, 0.5 wt% LBP coated NCA (NCA@LBP-2) possesses the good capacity retention of 92.3% at 1C in 2.7–4.3 V and 76.2% at high-voltage in 2.7–4.7 V. Moreover, the sample shows an outstanding rate capability even after cycled at 10C. Hence, this effective coating strategy on Ni-rich cathode material improves the cycling stability and rate capability under high-voltage condition and shows a good application prospect in the practical production of NCA.