Sodium-ion battery separators have high performance requirements and will have huge market demand in the future.

In a primary battery, the function of the separator is to separate the positive and negative electrodes, prevent the two electrodes from contacting and causing a short circuit, and at the same time serve as a channel for electrolyte ions. The performance of the separator directly affects the voltage, internal resistance, cycle life, safety and other characteristics of the battery, and is of outstanding importance. Sodium-ion batteries are mainly composed of positive electrodes, negative electrodes, electrolytes, separators, etc. The separator is one of its important components.

Sodium-ion battery separator materials need to consider permeability, barrier properties, and safety. Safety includes mechanical safety and thermal safety. In addition, material cost also needs to be considered. The working principle and product structure of sodium-ion batteries are basically the same as those of lithium-ion batteries. Most of the materials used are similar to lithium-ion batteries. The sodium-ion battery separator can use PP film and PE film commonly used in lithium-ion batteries.

Since sodium salt is used instead of lithium salt, the specific materials used in sodium-ion batteries will be somewhat different from those in lithium-ion batteries. The separator materials commonly used in lithium-ion batteries are used in sodium-ion batteries, which will reduce the transmission speed of sodium ions and affect the battery cycle performance. Compared with elemental lithium, elemental sodium is more active, and growth will occur on the separator and negative electrode of sodium-ion batteries. More sodium dendrites, sodium dendrites will puncture the separator, reduce battery energy density, and even cause battery short circuit. Therefore, sodium-ion battery separator performance requirements are higher.

Sodium-ion battery separators can use dry separators, wet separators, coated separators, etc. In comparison, dry separators are cheap; wet separators have the advantage of high strength and can inhibit sodium dendrite puncture; coated separators can improve the heat resistance of the product and have good moisture control capabilities. At present, the mass production of professional sodium-ion battery separators has not yet been developed in our country’s market.

According to the“China Sodium Ion Battery Separator Industry Market In-depth Research and Development Prospects Forecast Report 2023-2028” released by the Industrial Research Center , in the sodium-ion battery industry chain, separators account for 18%-19% of the output value. Compared with lithium-ion batteries, under the same battery power, sodium-ion batteries have greater demand for separators, mainly due to their energy density. And determined by volume characteristics. From 2023 to 2025, my country’s sodium-ion battery industry will enter an explosive period, and the demand for sodium-ion batteries will reach 200GWh by 2025. Against this background, the demand for sodium-ion battery separators will increase significantly.

Industry analysts said that in my country, the main companies with sodium-ion battery separator layout are: Enjie Co., Ltd., which has developed a “sandwich” structure The special functional separator for sodium-ion batteries can effectively improve the cycle life and rate performance of sodium-ion batteries, inhibit the formation of sodium dendrites, and improve battery safety; Chuanyi Technology has announced two sodium-ion battery separator patents, one for thermal Cellulose membranes with good stability and cellulose separators with good flame retardancy and heat resistance; Xingyuan Materials and Sinoma Technology all stated that the company’s lithium-ion battery separator products are suitable for sodium-ion batteries.