14 DAY TRIAL // Chinese scientists have always been very ingenious, just like their latest invention – an electrode for lithium-sulfur batteries based on pig bones, a very cheap and also renewable carbon source.
Rechargeable batteries are starting to be used more and more, all over the world, because not only there are more ecological, but in the end, they are cheaper too.
Lithium-sulfur batteries are very promising because they have a large storage capacity and are not very expensive, but they do have a couple of problems that need solving: they have a rather short life cycle and they lose active sulfur through electrochemical reactions in the battery.
The solution for the sulfur loss are porous carbon materials, since they can trap the sulfur in their pores, preventing it from reacting further, but preparing them takes many synthetic steps.
So, Yaqin Huang and his team from the Beijing University of Chemical Technology have carried out a research and found a novel source of porous carbon, in pig bone.
In order to obtain the porous carbon, the researchers crushed the pig bones to a powder, and then heated them to 450ºC, until they were carbonized.
Then they activated the carbon by adding potassium hydroxide, and heated the mixture, RSC reports.
Bones are organic and they mostly contain collagen and apatite crystals (bone minerals made out of calcium) that are dispersed in the collagen and act as natural templates of the porous structure.
They tested the effects of activation temperature on the new carbon/sulfur cathode and concluded that the carbon prepared at 850ºC had the highest surface area, the largest pore volume and best conductivity, and that it also maintained its structure up to 950ºC.
The cycling performance also seemed to be higher than that of normal cathodes with compact structures.
Huang explained that “the development of rechargeable batteries that can be coupled to renewable sources is becoming more important for clean and efficient energy storage.”
Leela Mohana Reddy, an expert in lithium ion batteries and supercapacitors at Rice University, Texas, US, added that “since the activation temperature in this process is very high, the real challenge will be synthesizing a highly porous carbon material at relatively ambient conditions.”
Nevertheless, “pig bone based porous carbon has great potential in the development of novel cathode materials for building the next generation of energy storage devices.”