Flexible and wearable electronics span a range of cutting-edge applications, from roll-up displays and implantable medical devices to smart communications and the Internet of Things. Such applications require high energy density power sources, and lithium-metal batteries are among the most promising due to their high theoretical capacity, light weight, and cost efficiency.

They are not, however, without flaws. Foremost, uncontrolled growth of lithium dendrites at the top of the fabric anode increases the risk of separator piercing, thus causing safety issues such as short circuits and battery fire during irreversible charging and discharging.

To address these issues, Li et al. proposed incorporating a 3D Janus current collector by a simple modification of the bottom side of carbon fabric (CC) with a lithiophilic gold layer. The result is a highly flexible, stable and safe lithium metal anode.

“In this work, a thin layer of gold is coated on one side [of the carbon fabric] to yield a Janus current collector,” said co-author Zijian Zheng. “Because of the high affinity between lithium and gold, the collector can effectively guild the deposition of lithium metal onto the gold side, placed away from the separator.”

The Janus gold layer was shown to guide dendrite deposition to the bottom of the carbon fabric, alleviating buildup via the lithium-free interface between anode and separator. This mitigates the issue of uncontrolled dendrite growth in flexible lithium batteries, effectively reducing the risk of short circuits and fire hazards. Additionally, the modification was shown to significantly extend battery life.

“This represents an important impact on the future development of high energy density and flexible lithium metal batteries,” Zheng said.

Source: “Au-coated carbon fabric as Janus current collector for dendrite-free flexible lithium metal anode and battery,” by Dongdong Li, Yuan Gao, Chuan Xie, and Zijian Zheng, Applied Physics Reviews (2022). The article can be accessed at http://doi.org/10.1063/5.0083830.

This paper is part of the Flexible and Smart Electronics Collection, learn more here.