Bee pollen could hold the answer to next generation battery research, according to a new study led by scientists at Purdue University, Indiana.
The team has been exploring how the unique microstructures found in allergen pollen grains could be used to provide a more energy efficient type of energy storage. The engineers were investigating ways to improve on lithium-ion batteries, used in today’s mobile phones and laptops, which typically contain a lithium cobalt oxide cathode, a carbon anode, and an electrolyte made from lithium salts.
Widely used as the carbon anode in this type of battery, graphite has many weaknesses. It is limited in storage capacity, and its preparation for use involves hazardous chemicals such as hydrofluoric and sulphuric acids – a process which is neither friendly to the environment, nor very cost efficient.
Lead researcher Vilas Pol, an associate professor in chemical engineering and materials engineering, has now explained that by turning pollen into a carbon anode with a more efficient microstructure than graphite, the team was able to create a battery which could store more energy than conventional graphite models.
The scientists took the pollen from honeybees and common wetland plant cattails, and formed little pieces of carbon by heating them to 600 degrees Celsius in a space filled with argon gas to prevent it from burning. The pollen-based carbon was then reheated to create more empty pockets in the structure, increasing its energy storage capacity.
Both types of pollen carbon were tested in lithium-ion batteries. The scientists discovered that cattail pollen had more energy-storing capacity, compared to the bee pollen. The study suggested that this could be because the cattail pollen has a more regimented structure, as it’s made of only one type of pollen. On the other hand, bee pollen is an amalgamation of many different plant pollens and therefore has a more irregular structure.
In future research, Pol is planning to look into how to improve cathode design, alongside the pollen-optimised anode. “This is just the beginning of better batteries,” he said.