It is estimated that sodium-ion battery only costs 70% of lithium iron phosphate battery in terms of comprehensive expense, making it widely applicable to low-speed e-bikes and power storage.

Recently, SEMCORP successfully developed “sandwich-structured” special separator for sodium-ion battery, thus filling in the market void. This separator is made of “base diaphragm + inorganic functional layer + organic functional layer”, which can effectively improve the recyclable life span and productivity of sodium-ion batteries. Meanwhile, by capturing the leaking of transition metals such as magnesium from anode materials, it prevents the formation of sodium dendrites, which can substantially improve battery’s safety.

As of Nov. 25, 2022, lithium carbonate can run up to 605,500 yuan/ton, a year-on-year jump of 201.09%. The sharp rise in the price of lithium carbonate substantially increased the cost of lithium-ion battery. In the face of booming development of EV and storage industries, finding an alternative and cheaper battery as a complement is a must in order to lower cost. Compared to the sky high price of lithium carbonate at 600,000 yuan/ton, the price of sodium carbonate can be less than 3000 yuan/ton. Sodium carbonate is not only cheap and abundant, but is also safe from being “strangled” by foreign powers.

Sodium-ion battery boasts low cost, sound safety with low temperature, high charging rate, etc., and can be widely applied to low-speed e-bikes and power storage. It is estimated that global demand for this kind battery will exceed 100GWh by 2025 and the corresponding demand for separator will exceed 2.5 billion square meters. At present, multiple industry leaders including CATL are increasingly fleshing out their sodium-ion battery industrial chains.

Separator is a requisite component for sodium-ion battery but the market currently lacks specialized sodium-ion battery separator. Traditional lithium-ion battery separator can be applied for sodium-ion batteries but has drawbacks such as poor maintenance of fluid and low conductivity of sodium ions, which can undermine the battery’s recyclability and increase surface electric resistance of batteries, and lead to formation of sodium dendrites on cathode surface. Sodium dendrites can pierce the separator and cause short-circuiting inside sodium-ion batteries, which can undermine the safety of sodium-ion batteries.

A leader of industry trends, SEMCORP established a technology team led by premier provincial-level science and technology experts in 2021 and has invested over 10 million yuan for R&D fund. The team successfully developed the “sandwich-structured” sodium-ion battery functional separator. This separator is made of base diaphragm + inorganic functional layer + organic functional layer, in which the inorganic functional layer has high thermal stability, which can effectively prevent magnesium leaking and enrichment materials, and has high transmission rate for ions, low conductivity for electrons, sound immersion rate and surface adhesion; the organic layer has a fairly wide electro-chemical window, which can effectively improve recyclable life span by 20%, reduce inner electric resistance by 10%, improve productivity by 15%, prevent formation of sodium dendrites, improve electric charge and the safety of batteries.

At present, Laboratory R&D on this new functional separator has been completed and it is being validated in accelerated commercialization.