Researchers at Tohoku University have developed a new class of polymeric solid electrolytes for lithium-ion batteries that are safer than commonly used electrolytes while maintaining the device’s conductivity.
The scientists explain that organic electrolytes such as liquid ethylene carbonate (EC) and their gels have been used as the preferred Li-ion electrolyte due to their ability to regulate their voltage resistance and ionic conductivity. However, they are very flammable. This research is published in the journal iScience.
Reregistration of the Battery Metal Test, On the other hand, solid polymeric electrolytes is considered safer than their EC electrolytes.
Substances such as polyethylene glycol (PEG) have been proposed as shock-resistant Li-ion electrolytes. However, PEG-based polymeric electrolytes crystallize near room temperature, causing the Li-ion conductivity to drop significantly to about 10-6 S/cm at room temperature.
“High ionic conductivity, suitable mechanical strength, and electrochemical stability are the main requirements for high-performance poly(ethylene oxide)-based electrolytes. However, the low ionic conductivity owing to the crystallinity of the ethylene oxide chain that limits the discharge rate and low-temperature performance has restricted the development and commercialization of these electrolytes.”
Lithium electrolytes that combine high ionic conductivity with a high lithium transference number are rare and are essential for high-power batteries. Here, we report hexagonal arranged porous scaffolds for holding prototype polyethylene glycol-based composite electrolytes containing solvate ionic liquid.
The appealing electrochemical and thermal properties indicate their potential as electrolytes for safer rechargeable lithium-ion batteries. The porous scaffolds in the composite electrolytes ensure better electrochemical performance towing to their shortened pores (sizes of 3-14 mm), interconnected pathways, and improved lithium mobility.
To solve this problem, the Tohoku group invented a new class of solid polymer electrolytes by combining a porous polymer film with pores as small as a few microns and a polyethylene-based optically linkable polymer electrolyte. glycol PEG.
Solid electrolyte The polymer realizes a wide potential window (4.7V), high Li-ion conductivity at 10-S/cm layer, equivalent to liquid and sufficient for practical use, and transmits a high Li-ion (0.39).
The Li-ion transferred in the electrolyte move in different directions due to natural diffusion.
The spacing is a few m to 10 m and does not always move linearly between the electrodes, which is one of the causes of the decrease in ionic conductivity. But the new study shows that the performance of optically bonded PEG-based solid polymer electrolytes has been improved by combining them with micrometer-sized porous membranes.
The solid polymer electrolyte should not only show high performance, the researchers say, but must also be effective in preventing the formation of lithium dendrites, which can lead to short circuits.