Study on wet-laid nonwoven separator of lithium-ion battery

In this paper, a new kind of wet-laid nonwoven material composed of highly fibrillated PPTA (para-phenylene terephthalamide) pulp is used in the preparation of a lithium-ion battery separator. Because the PPTA pulp is composed of fibrils and micro-fibrils, which are mostly less than 1 µm in diameter, the pore size of the separator could be well controlled to less than 1 µm. The effects of PPTA pulp on the pore structure of the separator, thermo-stability, electrochemical property and mechanical properties are researched. The results show that with the increase of PPTA pulp dosage, the pore size of separator is decreased. In addition, this type of separator shows excellent thermal stability. The strength retention of the nonwoven separator is 45% after it is stored at 180°C for 10 minutes, but the polyolefin membrane is completely molten under the same conditions.