Wood to supercapacitors

Sustainable highly conductive electrode materials from ultrathin carbon nanofiber aerogels derived from nanofibrillated cellulose.

nanowood, nanocarbon
Image: Wiley

Scientists in recent years have taken infest in making Carbon aerogels to use them within supercapacitor electrodes in electric cars and cell phones. Key necessities for supercapacitor anodes are an extensive surface area and conductivity, joined with a basic creation technique. Another developing issue in supercapacitor production – for the most part for cell phone and electric car innovations – is sustainability.

Now, Chinese scientists have now found a way to make these electrodes sustainably. Scientists have discovered a new way that allows them to create supercapacitor electrodes as carbon aerogels from cellulose nanofibrils, the abundant cell-wall material in wood.

The method is abundant, far less expensive, and sustainable source: wood pulp. Originally the main ingredient is not wood pulp, but nanocellulose present inside it.

Plant cell walls are stabilized by fibrous nanocellulose, and this extractable material has very recently stimulated substantial research and technological development. It forms a highly porous, but very stable transparent network, and, with the help of a recent technique–oxidation with a radical scavenger called TEMPO–it forms a microporous hydrogel of highly oriented cellulose nanofibrils with a uniform width and length.

Scientists attempted pyrolysis of supercritically or freeze-dried nanofibrillated cellulose hydrogel.

Scientists noted, “As it turns out, the method was not as straightforward as expected because ice crystal formation and insufficient dehydration hampered carbonization, according to the authors. Here, a trick helped. The scientists pyrolyzed the dried gel in the presence of the organic acid catalyst para-toluenesulfonic acid. The catalyst lowered the decomposition temperature and yielded a “mechanically stable and porous three-dimensional nanofibrous network” featuring a “large specific surface area and high electrical conductivity.”

During experiments, scientists found that their wood-derived carbon aerogel worked well as a binder-free electrode for supercapacitor applications. The material displayed electrochemical properties comparable to commercial electrodes. The method is an interesting and innovative way in which to fabricate sustainable materials suitable for use in high-performance electronic devices.

The study reported in the journal Angewandte Chemie.