Hydrogen micro-bubbles join fight against climate change

Hydrogen micro-bubbles join fight against climate change
Hydrogen micro-bubbles join fight against climate change

The Australian Research Council (ARC) recently announced a $654,642 grant to empower a team of researchers at ANU to continue development of high-density hydrogen storage. Hydrogen energy captured in microscopic bubbles will provide for safer transport and storage, a major boost for the clean energy economy. 

The new hydrogen storage technology stems from research into the use of layered materials in nanotechnology by Associate Professor Yuerui (Larry) Lu.

“Layered materials are made up of many sheets of ultra-thin layers, and each layer is only one or a few atoms thick,” Lu explained. “It is similar to a book that is made of many paper layers. Each ‘paper sheet’ is only one or a few atoms thick.”

The atoms within a layer are linked by chemical bonds, while consecutive layers are bonded by a much weaker force: physical adsorption. Thus, layered materials can be mechanically exfoliated layer by layer, Lu explained.

The hydrogen is stored between layer sheets in the form of nano-bubbles.

Expected benefits include “a remarkable energy density, high stability” which will improve “the capacity and robustness of low-cost hydrogen storage and transportation, reducing energy costs, and making hydrogen energy a more accessible and sustainable clean energy source for Australia,” the ARC announced.

Clean energy transition

Hydrogen is the most abundant chemical element, found everywhere in the universe. On earth, hydrogen is rarely found on its own. Instead, it is bound up with other elements in common substances such as water, methane, and propane.  

Hydrogen can be burned without releasing harmful emissions; the only byproduct is water. But it does require energy to produce, and, while technology for producing low-carbon hydrogen already exists, it is currently more expensive than other production methods and alternative fuels. 

But that will be changing soon. Major energy companies are investing in electrolysis-based hydrogen plants which will come online this decade. Meanwhile, solar and wind energy, which are limited by changing weather conditions, can be stored as hydrogen energy and then distributed during periods of higher demand. 

In the near future, safer and more affordable technology for storage and transportation will be needed to allow the hydrogen energy economy to grow. 

That is where Lu’s research comes in. Because hydrogen is highly flammable, safe storage and transportation is costly. High-pressure tanks are used to store hydrogen as a gas, while cryogenic temperatures are required to store it as a liquid.

With this new innovation, “each nanobubble is similar to a tiny hydrogen tank to physically store hydrogen gas,” Lu said. 

“In the traditional way, a high-pressure tank is required to store hydrogen, which is very expensive and could be dangerous. Here, we split the hydrogen into small units (in the form of nano-bubbles) and store them in solid materials. The high-pressure tank is not required.”

Lu and his team expect that hydrogen in the form of nanobubbles will be safely stored and transported at ambient pressure and temperature, a huge cost savings that will unleash the potential of an emerging sustainable energy sector that can help replace the burning of fossil fuels.

Origins of the hydrogen bubble sandwich

Lu and co-workers demonstrated in 2019 that they can create robust, and highly pressurised hydrogen nano-bubbles to be stored in layered materials.

Research Fellow Dr Juan Felipe Torres applied for and received funding from CECS Industry Engagement Advice and Investment Scheme to visit Japan and show Lu’s work to former colleagues at Toshiba Corporation. 

Toshiba signed on as a partner organisation and Torres joined as a chief investigator before applying for the ARC grant. Global Power Generation Australia and Evoenergy are also partner organisations.

Lu had been researching nanotechology in other arenas. His invention of an atomically thin lens, 2000 times thinner than a human hair, was reported on by the science program Scope and ABC News in 2016. 

“This hydrogen storage project, small lens, and very thin solar cells are all using the ‘layered materials’ that my group is working on,” Lu said.

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