An effective etching-induced coating strategy to shield LiNi0.8Co0.1Mn0.1O2 electrode materials by LiAlO2

Abstract

Nowadays nickel-rich LiNixCoyMn1-x-yO2 (0.5 < x < 1) cathode materials attract great research interests due to their high specific capacity in lithium ion batteries. However, poor cycling performance and serious safety concerns trade off their benefits. Here, we present an effective etching-induced coating strategy for surface modification of LiNi0.8Co0.1Mn0.1O2 cathode materials by LiAlO2. Hydrolysis of AlCl3 creates H+ to etch the hydroxide precursor of LiNi0.8Co0.1Mn0.1O2 and to induce oriented deposition of Al(OH)3 layer on surface of the hydroxide precursor, which is transformed into uniform γ-LiAlO2 coating on the LiNi0.8Co0.1Mn0.1O2 particles after the subsequent lithium impregnating and annealing. The 2.2 wt% LiAlO2-coated LiNi0.8Co0.1Mn0.1O2 cathode delivers a high rate capacity of 135.2 mAh g−1 at 10 C and long cyclability with capacity retention of 85.8% after 200 cycles at 0.5 C. In addition, the thermal stability of LiAlO2-coated LiNi0.8Co0.1Mn0.1O2 is significantly improved. The enhanced battery performances are due to partial Al3+ doping and Li+ conductive LiAlO2 coating layer that provides well-connected networks for Li+ transport, improves the structural stability and prevents core materials from the attack by side products.