Lithium-ion battery separators

Lithium-ion battery separators, together with electrolyte, positive electrode materials, and negative electrode materials, are an important part of lithium-ion batteries. They are also commonly referred to as battery separators, separator papers, porous membranes, ion exchange membranes, separation membranes, ion permeable membranes, etc.The diaphragm matrix material mainly includes polypropylene (PP) resin, polyethylene (PE) resin and additives. The matrix material has a direct relationship with the mechanical properties of the diaphragm and the degree of infiltration of the electrolyte.

Among the key performance determinants of lithium-ion battery capacity, cycle performance, and charge-discharge current density, the role of lithium-ion battery separators cannot be underestimated. Therefore, the diaphragm is usually required to have excellent chemical stability, thermal stability and mechanical stability, and to achieve physical characteristics such as consistency and safety.

The disadvantages of lithium-ion battery separators are mainly concentrated in the lower melting temperature and poor heat resistance. In recent years, with the maturity of diaphragm coating technology, after coating ceramics, boehmite, barium sulfate and other inorganic materials on diaphragms produced by dry or wet processes, the above-mentioned high temperature resistant coated diaphragms occur during charging and discharging. The integrity of the diaphragm can be maintained after a large area of heat is released, and the problem of poor heat resistance of the diaphragm can be solved well. Lithium-ion battery separators, through the coating of inorganic materials, will greatly improve the safety performance of lithium-ion batteries, expand application areas, and gradually enter the mid-to-high-end market covering power lithium-ion batteries.