Lithium-ion batteries (LIBs) are commonly used to power electronic devices such as mobile phones and laptop computers and are a popular energy source for electric vehicles (EVs) due to their high power density and great cycling stability. However, LIBs have impediments including safety issues and more energy density requirements that remain to be solved.
NAEPE enhances the safety and cycle life of high-energy density LIBs with its high ionic conductivity, non-flammability, and high voltage stability.
ITRI has developed the Networked Amide Epoxy Polymer Electrolyte for Solid State LIBs (NAEPE), an innovation that can minimize fire and explosion risks of high-energy density batteries. Unlike conventional LIBs that contain volatile and flammable organic liquid electrolytes, batteries with ITRI’s solid polymer electrolyte feature high ionic conductivity, non-flammability, high safety, and longer cycle life.
The NAEPE is formed via adding a unique cross-linking agent, i.e. Amide Epoxy Oligomer (AEO) with an initiator to polymerize and absorb the liquid electrolytes at ambient temperature. This polymerization process requires no additional heat or UV light, which allows the technology to be widely applied in the existing battery manufacturing process with low cost and easy processing.
ITRI’s NAEPE is also more stable and performs better than liquid electrolytes at high temperatures and voltage (4.4V). It can strengthen energy density of cells by 3.5% and achieve a 10 wt% reduction in liquid electrolyte use.
Another advantage of NAEPE is that it gives batteries a higher strength format, thus increasing battery safety and cycling stability. Nail penetration tests have shown that by using a stainless steel needle of 3 mm diameter to penetrate an NAEPE cell, the penetration resistance is 100 times higher than that of a liquid electrolyte cell. Moreover, the NAEPE cell during the test did not catch fire and had a slight temperature rise (to only around 150°C), while liquid electrolytes caught fire and the temperature rose up to 550°C.
The nail penetration tests show the NAEPE cell has a high strength format.
By developing NAEPE, ITRI is able to provide high-energy, high-safety solid state batteries with excellent cycle life. The simple production process and friendly material cost have attracted battery manufacturers including Amita, Formosa Plastics Corporation, CPC Corporation, and Gus Technology to cooperate with ITRI on material and battery verification. This technology is ideal for all kinds of portable communication equipment, energy storage systems and EVs, and will help industry capture new markets.
ITRI researchers have devoted themselves to improving LIB technologies and earned an R&D 100 Award with their NAEPE in 2020.