Optimally designed interface of lithium rich layered oxides for lithium ion battery

Particle morphology structure design combined with surface modification has been applied to improve the electrochemical properties of lithium rich layered oxides. Hollow spherical lithium rich layered Li1.2Mn0.54Ni0.13Co0.13O2 oxides with different shell thickness are synthesized by co-precipitation followed by calcination. The morphology and interior structure have been investigated by SEM and cross section, and their electrochemical properties have been evaluated to identify an appropriate shell thickness. Furthermore, a Zr compound coating layer has been applied to modify the interface between corrosive electrolyte and hollow spherical particles with an appropriate shell thickness. The Electrochemical impedance spectroscopy shows hollow spherical structure and Zr compound coating layer both can modificate the electronic and ionic transmission capacities and inhibit their deterioration during charge-discharge process at the same time. The HRTEM tests indicate that hollow spherical structure and Zr compound coating layer can dramatically suppress Mn dissolution in electrolyte and make the crystal structure more stable during the electrode process. Therefore, a surface modification combine with the hollow spherical structure (with an appropriate shell thickness) can effectively enhance these electrochemical properties of lithium ion layered oxides.