Enhanced electrochemical performance of Li1.18Ni0.15Co0.15Mn0.52O2 cathode modified with aluminosilicate solid acid

Abstract

Li-rich cathode material Li1.18Ni0.15Co0.15Mn0.52O2 is prepared by a sol–gel method and modified with aluminosilicate solid acid (Al2O3·SiO2) via an ultrasonic impregnation process. Compared with the pristine and Al2O3/SiO2-sole-modified counterparts, the Al2O3·SiO2 coating layer with high acid center strength on Li1.18Ni0.15Co0.15Mn0.52O2 material exhibits overall improved electrochemical performance. Galvanostatic charge–discharge tests at the current density of 200 mA g−1 displays the highest capacity retention of 72.5% and voltage retention of 95.1% after 200 cycles for Al2O3·SiO2-coated material. Meanwhile, a high rate capability of 99.2 mAh g−1 after 300 cycles is obtained with a good retention of 65.7% at the current density of 1 A g−1. The analysis of dQ/dV plots indicates the strong acid center strength of Al2O3·SiO2 coating layer on Li1.18Ni0.15Co0.15Mn0.52O2 cathode material can be favor of suppressing the voltage decay and reducing the side reactions between the electrode and the electrolyte.