Longer-lasting electric vehicles with dual-ion batteries

In the realm of electric vehicles, powered by stored electric energy, the key lies in rechargeable batteries capable of enduring multiple charge cycles. Lithium-ion batteries have been the poster child for this application. However, due to limitations in energy storage capacity and other associated challenges, the focus has shifted to an intriguing alternative known as dual-ion batteries (DIBs).

Dual-ion batteries utilise both lithium cations and counter anions simultaneously, offering a high energy density akin to traditional batteries. This allows them to store a substantial amount of energy. However, they face a hurdle due to the larger anions, causing expansion and contraction of the graphite anode material during charge and discharge, which can lead to decreased battery durability.

Rechargeable batteries that are capable of withstanding multiple charge cycles are crucial for electric vehicles. While lithium-ion batteries are suitable for this application, they possess limitations in energy storage capacity. As a result, researchers are now analysing the potential of dual-ion batteries (DIBs).

Duel-ion batteries use both lithium cations and counter anions simultaneously, offering a high energy density akin to traditional batteries. This allows them to store a substantial amount of energy. However, the larger anions can cause expansion and contraction of the graphite anode material during charge and discharge, which can lead to decreased battery durability.

A collaborative research team has addressed the durability issues of dual-ion batteries through innovative polymer binder research. The binder plays a critical role in securing various chemicals within rechargeable batteries. In this study, the researchers introduced a novel polymer binder that incorporates azide groups (N3-) and acrylate groups (C3H3O2). Azide groups form a robust covalent bond with graphite through a chemical reaction facilitated by ultraviolet light, ensuring the structural integrity of graphite during its expansion and contraction. Meanwhile, acrylate groups facilitate the connection between the graphite and the binder, even if the bond is disturbed.

Experimental results showed that dual-ion batteries equipped with the binder maintained exceptional performance, even after 3500 recharge cycles. These batteries also demonstrated switch charging capabilities, with about 88% of the original capacity being restored within two minutes. Lead researcher Professor Soojin Park said dual-ion batteries are cost-effective and leverage abundant graphite resources. “This research will stimulate further exploration of dual-ion batteries, extending beyond electric vehicles to various other applications,” Park said.

The findings from this study were published in Advanced Materials.

Image credit: iStock.com/Golden Sikorka