Bourbon waste transformed into energy storage materials
- C&I Storage Energy Storage Research
Marin Holt
- 0
- 6 minutes read
- Institution: University of Kentucky
- Waste material: stillage
- Process: hydrothermal carbonization
- Energy storage improvement: up to 25 times more energy
Researchers at the University of Kentucky have developed a process that turns bourbon distillery waste into carbon electrodes for supercapacitors, building energy-storage devices that hold up to 25 times more energy per kilogram than conventional versions. The team presented the work at the American Chemical Society (ACS) Spring 2026 meeting, held March 22–26, 2026, according to an ACS announcement dated March 25, 2026.
What Was Reported
Kentucky produces about 95% of the world’s bourbon, and each batch leaves behind 6 to 10 times its final volume in a wet waste grain called stillage, ACS reported. Graduate researcher Josiel Barrios Cossio and colleagues convert that soupy stillage directly into carbon material using hydrothermal carbonization — a high-pressure, high-temperature process likened to pressure cooking — which eliminates the costly drying step normally required to reuse the waste.
Per Interesting Engineering’s account of the work, the team used a 10-liter reactor to turn the stillage into a black powder, then refined it two ways: heating to about 200°C (392°F) produced hard carbon suited to trapping lithium ions, while adding potassium hydroxide and heating to roughly 800°C (1,472°F) produced highly porous activated carbon. Double-layer capacitors built with the activated carbon reached an energy density of 48 Wh/kg, meeting commercial standards; a hybrid lithium-ion supercapacitor pairing a hard-carbon electrode with an activated-carbon electrode delivered the headline 25x improvement in energy stored per kilogram.
Why It Matters
Supercapacitors charge and discharge far faster than conventional batteries and are used where rapid power delivery matters, including grid power-quality and short-duration storage roles. Sourcing their electrode carbon from an abundant agricultural waste stream — rather than fossil-derived or specially grown feedstocks — could lower both cost and the environmental footprint of the materials, while giving distillers a higher-value outlet for stillage that is otherwise difficult to transport and expensive to dry.
The researchers say producing both required electrode types — hard carbon and activated carbon — from a single waste source is a notable result, because a high-performance hybrid device normally draws its two electrodes from different materials.
Critical Perspective
The results were demonstrated in coin-cell-scale prototypes, and the 25x figure compares the hybrid device against conventional versions rather than against the best commercial supercapacitors across every metric. The team has stated it is now shifting toward commercialization and scale-up — the stage where lab-scale carbon chemistry most often runs into reproducibility, yield, and cost hurdles. Whether stillage-derived electrodes can match commercial cycle life and be manufactured economically at volume remains to be proven.
Sources
- American Chemical Society — From stillage to storage: Researchers turn bourbon byproducts into supercapacitors
- IEEE Spectrum — Bourbon Waste Could Provide Next-Gen Supercapacitor Components
- Interesting Engineering — US scientists turn bourbon waste into supercapacitors with 25x energy storage
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