Hydronium battery could help unlock grid storage

Scientists at Oregon State University have developed the world’s first battery to use hydronium ions as the charge carrier.

Hydronium, or H3O+, is a positively charged ion produced when a proton is added to a water molecule. The researchers discovered that hydronium ions could be reversibly stored in a crystalline electrode material consisting of perylenetetracarboxylic dianhydridem, or PTCDA.

According to their work, published in the German Chemical Society’s Angewandte Chemie International Edition, the battery uses dilute sulphuric acid as the electrolyte. The OSU team claims the battery is particularly suitable for high-power energy storage, such as that required to accommodate large quantities of wind and solar on the grid.

“This may provide a paradigm-shifting opportunity for more sustainable batteries,” said Xiulei Ji, assistant professor of chemistry at OSU and the corresponding author on the research.

“It doesn’t use lithium or sodium or potassium to carry the charge, and just uses acid as the electrolyte. There’s a huge natural abundance of acid so it’s highly renewable and sustainable.”

In the lab, the team observed a large dilation of the PTCDA lattice structure during intercalation, the process where it receives ions between its layers. This indicated that the electrode was being charged and that the PTCDA structure expanded from the addition of hydronium ions, rather than extremely tiny protons.

According to the OSU scientists, the ions also travel with comparatively low “friction”, which translates to high power. Meanwhile, the PTCDA material has a lot of internal space between its molecule constituents, delivering good capacity.

“It’s not going to power electric cars,” said Ji. “But it does provide an opportunity for battery researchers to go in a new direction as they look for new alternatives for energy storage, particularly for stationary grid storage.”