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Concordia researchers discover organic compounds to replace heavy metals in batteries

Chemical and materials engineers Zhibin Ye and Xudong Liu create battery with sustainable high-energy organic cathode materials that enhance energy density
April 12, 2021
By Elena Parial

Portrait of Zhibin Ye Zhibin Ye: “We can design organic cathode materials that have high stability, while achieving higher levels of energy density than market-dominating inorganic metal-oxide-based cathode materials.”

The world has become dependent on battery-powered technology to run daily life. From our cell phones to our electric vehicles, batteries of all shapes and sizes keep us connected to each other.

A common criticism of alternative solutions for portable energy is that the materials used do not hold a charge similar, or better, than the traditional lithium-ion battery.

Zhibin Ye, professor in the Department of Chemical and Materials Engineering at the Gina Cody School of Engineering and Computer Science, addresses these issues in his newest research paper, “Nitroaromatics as High-Energy Organic Cathode Materials for Rechargeable Alkali-Ion (Li+, Na+, and K+) Batteries.” The research was conducted by Ye and his post-doctoral fellow, Xudong Liu, at Concordia’s new Applied Science Hub.

What are nitroaromatics?

Nitroaromatics are a group of nitro (NO2)-containing aromatic organic compounds that can be synthesized from abundant organic sources. While they were historically considered too unstable to use in batteries, Ye’s research finds, for the first time, a way around that problem.

“We discovered nitroaromatic organic cathode materials that have high electrochemical stability, while achieving higher levels of energy density compared to the inorganic metal oxide-based cathode materials used exclusively in today’s lithium-ion batteries,” says Ye. “Energy density is a major limitation with the current lithium-ion battery technology, which means that in order to carry a longer charge, the battery needs to be larger and heavier.”

The researchers used small coin-sized batteries to test the approach. They are lighter and less costly compared to their inorganic counterparts and circumvent the ethical and environmental toll associated with the metal extraction mining process.

The next step is to test the performance in cylindrical batteries to prepare the technology for the consumer market and increase practical applications.

Portrait of Xudong Liu Xudong Liu is a post-doctoral fellow conducting research with Ye at Concordia’s new Applied Science Hub.

The impact on global waste

“As chemical engineers, we design solutions to optimize structure and performance of components,” explains Liu. “Discovering sustainable, organic sources for batteries that can provide stability and increased energy density can change the way we think about waste.”

Non-recyclable plastic waste has also been shown to store electric energy after functionalization with nitro groups. For example, polystyrene waste can be turned into nitrated polystyrene, which then becomes electrochemically active.

“We want to lower the global waste output by using it to build a sustainable energy source that addresses a growing need,” says Liu.

Weight for it

According to Ye, “there are three key challenges that we face with today’s batteries”:

  1. Energy density: Because of the heavy metals used in the cathodes, batteries are heavy. Their weight limits energy density.
  2. Toxicity: Batteries have a large environmental footprint because the heavy metals used in their composition are toxic.
  3. Unsustainable mining: These metals are mined from natural resources with limited abundances and are unsustainable. As demand for batteries rises, the cost will also rise and access to these raw resources will be more and more limited.

Experts project 11 million tonnes of lithium-ion batteries will be discarded between 2017 and 2030, and distributed for processing throughout the world. A 2019 Ipsos study revealed that Canadian consumers recycled almost 3 million kilograms of household batteries, a nine percent increase from the year prior.

The environmental footprint of recycling batteries is notable, and a key barrier to making electric vehicles truly environmentally friendly and more affordable. The battery pack accounts for a quarter of the cost of producing an electric vehicle.

The cost of zero-emissions policies

Our dependency on lithium-ion batteries will continue to increase. In 2017, the World Bank forecasted that global demand for lithium will skyrocket by 965 per cent by 2050.

The forecast is based on the fact that battery-powered electric vehicles are undoubtedly the future in transportation. Transport Canada aims to see annual sales of electric vehicles increase to 2.7 million in 2030. 

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