Enhanced electrochemical capabilities of lithium ion batteries by structurally ideal AAO separator

Abstract

In this study, a novel inorganic separator, porous anodic aluminum oxide (AAO), is introduced for a rechargeable lithium ion battery system. The highly ordered AAO gives rise to an ideal structure for battery separators with appropriate porosity (67.4 %), extremely low tortuosity, and thermal durability. The prepared AAO separator has average pore sizes of 75 nm and thickness of 54 μm, which leads to enhanced ionic conductivity (2.196 mS cm⁻¹), discharging capacity at high current rates (20.13 mA h g⁻¹ at 10 C), and capacity retention (82.9%). Moreover, a computer simulation (COMSOL) model shows that the ideal AAO separator structure induces stable lithium ion battery operation in wide ranges of current rate, due to effective suppression of Li dendrite formation. The AAO separator has a strong potential in massive energy storage systems and electric vehicles.