A international team of researchers, led by Lancaster University in the UK and Jilin University in China, reports the first organically synthesized sp‐sp3 hybridized porous carbon, OSPC‐1. The new carbon shows electron conductivity, high porosity, the highest uptake of lithium ions of any carbon material to‐date and the ability to inhibit dangerous lithium dendrite formation.
As described in a paper in the journal Angewandte Chimie International Edition, the new carbon exhibits “exceptional potential” as anode material for lithium‐ion batteries (LIBs) with high capacity, excellent rate capability, long cycle life and potential for improved safety performance.
The scientists discovered that OSPC-1 is able to store more than twice as many lithium ions, and therefore power, as graphite at the same mid-range speed of charging.
In addition, OSPC-1 is able to store lithium ions at more than double the rate as graphite—i.e., charging speeds can be twice as fast. Discharge speeds can also be vastly improved with OSPC-1, which means it can also be used to power more energy-hungry applications.
Structures of carbon materials. Zhao et al.
OSPC-1 was created at the molecular level using a complex technique called Eglinton homocoupling. This involves removing silicon from carbon-silicon groups to produce carbon-to-carbon links. The resulting structure is amorphous, very stable, and, crucially, highly conductive.
Another major advantage of OSPC-1 is its safety. It does not form dendrites.
OSPC-1 also appears to be much more longer-lasting than graphite. The team of scientists tested it over 100 charging and discharging cycles and there were no signs of deterioration. Graphite expands and contracts each time it is charged and discharged, which makes it susceptible to cracking. The open-framework structure of OSPC-1 means it is less brittle and not as prone to these weaknesses.
However, graphite is the industry standard because it is very cheap to produce and easily obtainable. The researchers acknowledge that OSPC-1 would be more costly to produce, at least initially. Therefore, the researchers believe the most likely early applications would be for situations where safety is the paramount consideration—such as within space satellites and aircraft.
The research benefitted from funding from the Royal Society, the Engineering and Physical Sciences Research Council in the UK, the National Natural Science Foundation of China.
Zhao, Z., Das, S., Xing, G., Fayon, P., Heasman, P., Jay, M., Bailey, S., Lambert, C., Yamada, H., Wakihara, T., Trewin, A., Ben, T., Qiu, S. and Valtchev, V. (2018), “A 3‐D Organically Synthesized Porous Carbon.” Angew. Chem. Int. Ed. doi: 10.1002/anie.201805924