A porous ceramic separator prepared from natural minerals: Research on the mechanism of high liquid absorption and electrochemical properties of mineral material separator

Abstract

Using three natural minerals (albite, quartz, and kaolinite) as raw materials, ammonium bicarbonate as a pore former, solid-phase sintering method is used to prepare porous ceramic separators for lithium-ion batteries. The porous ceramic separator has excellent thermal stability with the thermal stability temperature of 1100 °C. Rich three-dimensional pore structure and higher porosity (56.98%) of porous ceramic separator is beneficial to fast Li+ transport. Density functional theory calculation reveals that the lone pair electrons on the surface of albite and quartz (main components of porous ceramic) play an important role on the adsorption of electrolyte. The smaller electrolyte adsorption energies of albite and quartz (−2.48 eV and −0.18 eV) than commercial PP separator (−0.06 eV) promote the electrolyte affinity and the electrolyte uptake for porous ceramic separator. The cell assembled with the porous ceramic separator shows very good cycle performance and remarkable rate capability. When the charge/discharge rate is 10 C, the discharge specific capacity of the cell with porous ceramic separator can reach 91.31 mAh g−1, which is 46% higher than that of the cell with commercial PP separator (62.54 mAh g−1). Therefore, porous ceramic separators have broad application prospects in lithium-ion batteries that require high-power charging and discharging.