Chemists at Oregon State University have discovered that one or more organic compounds in a family that traditionally has been known as pollutants could offer an important advance toward the manufacture of inexpensive, reliable batteries.

Their research has shown that at least one of the compounds known as polycyclic aromatic hydrocarbons (PAHs) can function as a potentially long-lasting and high-performance cathode in “dual-ion” batteries. Such batteries would contain a carbon electrode as the anode and solid PAH as the cathode, with no need for the rare or costly metal elements now typically used.

In dual-ion batteries, upon charging, anions migrate into the lattice of the positive electrode and cations move into the structure of the negative electrode. Image credit: Oregon State UniversityTraditionally thought of as pollutants, PAHs are usually products of combustion—anything from a campfire to automobile exhaust or a coal-burning power plant—and pose significant concerns as toxins and carcinogens, particularly when inhaled. But in this study, scientists found that at least one PAH compound, coronene, in a safe, crystallized solid form makes a high-functioning electrode material with promising characteristics in dual-ion batteries.

“Prior to this work, PAHs were not considered stable when storing large anions,” says Xiulei (David) Ji, assistant professor of chemistry. “We found that coronene crystalline solid, a PAH, can lose electrons and provide a good capacity of anion storage while being structurally and chemically stable. Coronene had good performance as an electrode and the ability to have a very long cycle life, or the number of charges and discharges it can handle.”

Avoiding the use of metals in the electrodes makes dual-ion batteries a sustainable option, Ji says. While graphite cathodes can also do this, a serious obstacle to their use is that they operate at levels hostile to the non-aqueous solvents in the electrolyte. The batteries based on coronene largely eliminate this problem and would significantly improve the maintenance cost and sustainability of a stationary battery system.