Organic molecules could enable more sustainable batteries

Researchers at York University have discovered a way to make lithium-powered batteries more environmentally friendly while retaining performance, stability and storage capacity. Their research has been published in the journal Batteries & Supercaps.

Lithium-ion batteries use toxic, heavy metals which can impact the environment when they are extracted from the ground and are difficult to dispose of safely. Cobalt is one of those heavy metals, used in battery electrodes. Part of the problem is that lithium and cobalt are not abundantly available, and supplies are dwindling.

Professor Thomas Baumgartner and his team believe the use of organic materials is the way forward, and are busy developing and testing new molecules to find the right ones to replace the rare metals currently in use. Prof Baumgartner explained, “Organic electrode materials are considered to be extremely promising materials for sustainable batteries with high power capabilities.”

The team’s latest breakthrough is the creation of a carbon-based organic molecule that can replace the cobalt now used in cathodes or positive electrodes in lithium-ion batteries. The new material addresses the shortcomings of the inorganic material while maintaining performance.

“Electrodes made with organic materials can make large-scale manufacturing, recycling or disposing of these elements more environmentally friendly,” Prof Baumgartner said. “The goal is to create sustainable batteries that are stable and have equally as good if not better capacity.

“With this particular class of molecules that we’ve made, the electroactive component is very suitable for batteries as it’s very good at storing electrical charges and has good long-term stability.”

Prof Baumgartner and his group previously reported on the electroactive component in a paper published in the journal Advanced Energy Materials. He noted, “We have optimised this electroactive component and put it in a battery. It has a very good voltage, up to the 3.5 V, which is really where current batteries are now. It’s an important step forward in making fully organic and sustainable batteries.”

Prof Baumgartner, along with postdoctoral researchers Colin Brides and Monika Stolar, has also demonstrated that this material is stable in long-term operation with the ability to charge and discharge for 500 cycles. One of the downsides of inorganic electrodes is that they generate significant heat when charging and require limited discharging rates for safety reasons. This new molecule addresses that shortcoming.

The next step, Prof Baumgartner said, is to improve the capacity further. His team is currently developing the next generation of molecules that show promise in being able to increase current capacity.

Image credit: ©stock.adobe.com/au/sdecoret

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