Carbon nanotube forest developed as cathode for next-generation aluminum secondary batteries

Team led by Prof. Young-Soo Yun of KU-KIST Graduate School of Converging Science and Technology publishes results in Chemical Engineering Journal

▲ From left: Master’s student Jong-Chan Hyun and Professor Young-Soo Yun of KU-KIST Graduate School of Converging Science and Technology

The team led by Professor Young-Soo Yun of the KU-KIST Graduate School of Converging Science and Technology fabricated 3D carbon nanotubes through chemical vapor deposition using hydrocarbon produced from waste polyolefin masks, and significantly lowered the concentration resistance of the resulting aluminum-metal secondary batteries.

Jong-Chan Hyun, a master’s student of the KU-KIST Graduate School of Converging Science and Technology, conducted experiments under the supervision of Professor Young-Soo Yun, and cooperated with Son Ha, a student of the integrated master’s and doctoral program, the team under Professor Hyung-Kyu Lim of Kangwon National University, the team under Professor Hyoung-Joon Jin of Inha University, and the team under Dr. Hee-Dae Lim of Korea Institute of Science and Technology (KIST). The paper titled “Waste-induced pyrolytic carbon nanotube forest as a catalytic host electrode for high-performance aluminum metal anodes” was published online in the Chemical Engineering Journal on February 22.

Aluminum secondary batteries can use aluminum metal anodes that deliver high specific/volumetric capacities of 2,980 mA h g-1/8,060 mA h cm-3. Their high energy densities and high output make them a suitable power source for electric vehicles and urban air mobility (UAM). However, the use of carbonate/glyme-based organic electrolytes leads to the formation of an oxide layer on the surface of aluminum metal, which interferes with the transport of ions. Past studies have addressed this issue by using ionic liquid electrolyte systems to achieve reversible aluminum metal anodes.

A problem with ionic liquid electrolytes, however, is that the adsorption of aluminum ions (negative electric charges) on the aluminum cathode leads to phase transition, producing a large resistance and negatively impacting battery performance. This study resolved this issue by fabricating 3D carbon nanotubes through chemical vapor deposition using the hydrocarbon gas produced from waste masks. The resulting carbon nanotube forest was utilized as a catalytic host electrode for use in high-performance aluminum secondary batteries. It exhibited high coulombic efficiencies of 99% and great cycling stabilities of over 1,000 cycles. Additional tests were performed with a commercial graphite cathode capable of reversibly storing anions, and the proposed dual-ion rechargeable batteries were verified as a practical technology for electric vehicles and UAM.

Professor Young-Soo Yun said, "This study holds significance in fabricating nanocarbons from waste plastic (used masks) for use as electrodes in next-generation aluminum secondary batteries. With the increasing cost of lithium and the development of devices with higher energy density requirements, aluminum secondary batteries are promising alternatives due to their affordability, abundance, and larger capacity per volume.”

▲ Data showing the material properties of 3D carbon nanotubes fabricated through chemical vapor deposition using the hydrocarbon gas obtained from waste polypropylene masks