A rather interesting new approach to stabilizing the cathodes of Lithium-Sulfur (Li-S) batteries was recently explored by researchers at the China University of Geosciences — stabilization achieved through the addition of DNA.
Apparently, all that it takes is the addition of a “fine” amount of DNA into a carbon/sulfur composite to allow for a significant improvement to cyclic performance — via the “anchoring” of the soluble polysulfides that typically lead to performance degradation.
After testing, the “DNA-decorated” electrode possessed a discharge capacity of 771 mAh·g-1 at 0.1 C after 200 cycles (retention 70.7% of the initial) — meaning a roughly 3-fold increase in capacity retention over 200 charge-discharge cycles.
Here’s the abstract for the work:
Prohibiting lithium polysulfides from being dissolved to electrolyte is the most critical challenge for pursuing high-performance Li/S batteries. Taking full advantage of interactions between polysulfides and functional groups of third-party additives has been proven to be an efficient strategy. In the present work, we selected DNA to decorate CMK-3/S cathodes. The –P=O and =N– sites of the constituent deoxyribonucleotides of DNA are demonstrated to be capable of anchoring polysulfides through our DFT calculations. The experimental results show that adding a small amount of DNA into the CMK-3/S composite significantly improved the cyclic performance. In particular, with a moderate DNA loading rate, the DNA post-loading procedure resulted in a discharge capacity of 771 mA h g−1 at 0.1 C after 200 cycles (70.7% retention of the initial), which yielded slightly improved performance as compared to the DNA pre-loading procedure. The proposed DNA decorating scheme may provide an applicable technical solution for developing high-performance Li/S batteries.
Interesting work. It should be noted here that the DNA used in the research was obtained and utilized somewhat economically — it was simply obtained via dissolving salmon sperm DNA powder in deionized water, which was then ultrasonically interspersed with CMK-3 carbon. The resulting mixture was then slowly evaporated (ensuring uniform absorption of all DNA strands into the substrate), and this substrate was then coupled together with sulfur via the typically used melting-diffusion procedure.
According to the researchers behind the work, “the DNA-decoration strategy for C/S electrodes can be facilely implemented in industry and provides a commercially feasible choice for pursuing high-performance lithium-sulfur batteries.”
The new findings are detailed in a paper set to be published in the RSC Journal of Materials Chemistry A.
Image Credit: China University of Geosciences
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