Seaweed is an edible algae in many Asian cuisines. However, researchers have found another use for it: as a material to help boost the efficiency of superconductors, lithium-ion batteries, and fuel cells.
“Carbon-based materials are the most versatile materials used in the field of energy storage and conversion,” says Dongjiang Yang, Ph.D. of the research team. “We wanted to produce carbon-based materials via a really ‘green’ pathway. Given the renewability of seaweed, we chose seaweed extract as a precursor and template to synthesize hierarchical porous carbon materials.” The project opens up a new possibility of using earth-abundant materials to synthesize and enhance future high performance and multifunctional carbon nanomaterials for energy storage and catalyst on large scale productions.
Source: Algae World News
Conventional carbon materials like graphite have been an essential part to creating today’s energy sources. To jump to the next generation of lithium-ion batteries and other energy and fuel sources, an even better, more abundant, and more sustainable material is needed, says Yang.
Considering these factors, Yang turned to the sea to find a solution. He worked with his colleagues from Qingdao University in China and Los Alamos National Laboratory in the U.S. at the Griffith University in Australia to synthesize porous nanofibers from seaweed extract. Binding metal ions like cobalt to the alginate molecules created nanofibers with an “egg-box” structure, with the alginate molecules surrounding the metal ions. “This architecture is key to the material’s stability and controllable synthesis,” says Yang.
Tests have shown that the seaweed derived material had a huge reversible capacity of 625 milliampere hours per gram, which is a lot more compared to the 372 mAhg-1 capacity of traditional graphite anodes for lithium-ion batteries. This capacity could double the range of electric cars if the cathode material is of equal quality. The egg-box fibers also performed as well as platinum based catalysts, except with a better long-term stability. Finally, it has shown that it had a high capacitance as a superconductor material at 197 Farads per gram, which could be applied in zinc-air batteries and supercapacitors.
The researchers had published their initial results in the journal ACS Central Science in 2015 and since then, have been developing the materials further by suppressing certain defects in the seaweed based, lithium-ion cathodes that sometimes block the movement of lithium ions and inhibit battery performance. They have also recently developed a new approach that uses red algae-derived derived carrageenan and iron to make a porous sulfur-doped aerogel with a high surface area, making it a good candidate to use in lithium-sulfur batteries and supercapacitors.
They had presented their findings at the 253rd National Meeting & Exposition of the American Chemical Society (ACS) last April 5.