JAIST synthesizes new polymer material with high-density ionic liquid structure

Professor Noriyoshi Matsumi and Graduate Student Amarshi Patra of the Materials Chemistry Frontiers Research Area at the Graduate School of Advanced Science and Technology at the Japan Advanced Institute of Science and Technology (JAIST), announced the preparation of a new polymerized ionic liquid with a high-density structure from polyfumaric acid, a polymeric material synthesized from raw materials derived from biological resources. Polymerized ionic liquids are expected to be widely applied as functional materials for various energy devices, biomedical materials, and sensing materials. The results were published in the international journal Advanced Energy Materials on September 12.

In this research, fumaric acid ester was first subjected to radical polymerization using azobisisobutyronitrile (AIBN) as an initiator to synthesize polyfumaric acid ester. Polyfumaric acid was obtained by dialysis after treatment with a KOH solution at 100℃ for 12 hours. Allylmethylimidazolium chloride was separately treated with an ion-exchange resin to prepare allylmethylimidazolium hydroxide. By neutralizing the prepared allylmethylimidazolium hydroxide with the initially produced polyfumaric acid, the researchers succeeded in obtaining a high-density ionic liquid (PMAI).

When used as a graphite anode binder for lithium-ion secondary batteries, it facilitated rapid charge−discharge. When used as a hard carbon anode binder for sodium-ion secondary batteries, a discharge capacity twice that of existing PVDF binder systems was achieved.

The constructed battery systems showed high durability, with the lithium-ion battery showing 80% capacity retention after 750 cycles and the sodium-ion battery showing 96% capacity retention after 200 cycles.

Matsumi said, "This material system will add a new group of attractive high-performance materials to polymerized ionic liquids, a material group that originated in Japan when discovered by Professor Ohno (former president) of the Tokyo University of Agriculture and Technology and his colleagues. The material group has been the subject of active global research ever since. It is anticipated that this material system will find applications not only in the field of batteries but also in various other applications. In battery applications, the metal-ion diffusion capacity is remarkably improved, which is expected to be beneficial for improving charge and discharge capabilities. Another feature is improved adhesion to substrates due to multipoint interactions caused by the high density of functional groups."

Journal Information
Publication: Advanced Energy Materials
Title: Densely Imidazolium Functionalized Water Soluble Poly(Ionic Liquid) Binder for Enhanced Performance of Carbon Anode in Lithium/Sodium-Ion Batteries
DOI: 10.1002/aenm.202403071