Japan research team reports on new organic electrodes for high-capacity batteries
29 October 2011
A research team in Japan reports on the demonstration of high capacity, organic tailored batteries using organic molecules with degenerate molecular orbitals (MOs) as electrode active materials in a paper in the journal Nature Materials.
Research on organic electrodes has been underway for more than 25 years, as the technology in theory offers the possibility of building greener and more sustainable Li-ion batteries than those built from non-renewable, inorganic materials. However, such attempts have been characterized by low capacities or other limitations.
In 2008, researchers at Université de Picardie Jules Verne in France reported on a new renewable organic electrode material—the oxocarbon salt Li2C6O6—for lithium-ion batteries. That material showed a reversible capacity as high as 580 mAh g-1 for a specific energy density of about 1,300 Wh kg-1 of active material. However, it also showed a relatively poor cycle life. (Earlier post.)
Secondary batteries using organic electrode-active materials promise to surpass present Li-ion batteries in terms of safety and resource price. The use of organic polymers for cathode-active materials has already achieved a high voltage and cycle performance comparable to those of Li-ion batteries. It is therefore timely to develop approaches for high-capacity organic materials-based battery applications.
—Morita et al.
Morita et al. investigated trioxotriangulene (TOT), an organic open-shell molecule, with a singly occupied MO (SOMO) and two degenerate lowest-unoccupied MOs (LUMOs). A tri-tert-butylated derivative ((t-Bu)3TOT) exhibited a high discharge capacity of more than 300 Ah kg−1, exceeding those delivered by Li-ion batteries. A tribrominated derivative (Br3TOT) was also shown to increase the output voltage and cycle performance up to 85% after 100 cycles of the charge–discharge processes.
Resources
Yasushi Morita et al. (2011) Organic tailored batteries materials using stable open-shell molecules with degenerate frontier orbitals. Nature Materials DOI: 10.1038/nmat3142
This is another potential avenue to mass produce affordable e-storage units. It seems that about one dozen different improved battery technologies may become a reality by 2020 or shortly thereafter.
Interesting decade ahead for electrified vehicles.
Posted by: HarveyD | 29 October 2011 at 08:28 AM