Influence of integrated microstructure on the performance of LiNi0.8Co0.15Al0.05O2 as a cathodic material for lithium ion batteries

Abstract

Microstructures of active materials may definitively determine the performance of lithium ion batteries. Herein, we develop a facile approach to synthesize porous LiNi0.8Co0.15Al0.05O2 (NCA) with uniform Al distribution by a two-step solid reaction with assistance of spray drying. Relative to the randomly aggregated counterpart, the NCA microspheres with an integrated framework and porous structure result in not only a profitable accessibility of the electrolyte, but also a favorable interfacial behavior. The porous NCA spheres exhibit a superior electrochemical performance with a discharge capacity of 202.1 mA h g-1 at 0.1C and 151 mA h g-1 at 2C, and capacity retention of 74.5% after 500 cycles at 2C. These are ascribed to the integrated network accumulating the stress generated during cycling to maintain the structural stability of the spheres. As a result, less solid electrolyte interphase (SEI) film is formed at the interface of the resulting electrode, consequently leading to a lower resistance of charge transfer, and better rate capability and cycling performance, compared to those of the electrode with the aggregated counterpart. Thereby, a purposeful engineering of the microstructures of the NCA materials would be important to achieve an optimal electrochemical performance of the electrode material.