Battery-like storage device from bourbon waste stores up to 25 times more energy per kilogram

University of Kentucky researchers converted wet bourbon stillage into carbon electrodes using hydrothermal carbonization and built hybrid lithium‑ion supercapacitors that the team reports can store up to 25 times more energy per kilogram than conventional supercapacitors. The results were presented at the American Chemical Society Spring 2026 meeting.

Kentucky produces most of the world’s bourbon, and distilling generates large volumes of wet grain waste called stillage. Researchers at the University of Kentucky developed a process to convert this wet stillage into carbon materials using hydrothermal carbonization. They used those materials to make both activated carbon electrodes and hybrid lithium‑ion supercapacitors. The team reported devices that store substantially more energy per kilogram than conventional supercapacitors and presented the work at the American Chemical Society Spring 2026 meeting. Key facts: - Distillation produces stillage in volumes reported as six to 10 times the final bourbon volume. - Researchers collected stillage samples from distilleries in Kentucky, Illinois and Canada for the study. - They used a 10‑liter reactor under heat and pressure to transform wet stillage into a black carbon powder and then produced two types of carbon electrodes from that powder. - Coin‑sized conventional supercapacitors built with the activated carbon stored up to about 48 watt‑hours per kilogram, similar to commercial supercapacitors. - Hybrid lithium‑ion supercapacitors made from stillage‑derived activated and hard carbon electrodes and infused with lithium ions were reported to store up to 25 times more energy per kilogram than the conventional supercapacitors tested. Summary: The study demonstrates a method to turn bourbon stillage into carbon electrodes and to build hybrid lithium‑ion supercapacitors with much higher reported energy density than conventional supercapacitors. The researchers are studying how energy storage works inside the stillage‑derived devices and plan life‑cycle, economic and feasibility analyses to evaluate whether the process can be scaled and how it might be applied.