A new lithium-sulfur battery that demonstrates cycle performance that’s comparable to that offered by currently available commercial lithium-ion batteries and possesses roughly twice the energy density has been developed by an international team of researchers from South Korea and Italy.
This research team — which was led by researchers from Hanyang University — utilized a highly reversible dual-type sulfur cathode (solid sulfur electrode and polysulfide catholyte) and a lithiated Si/SiOx nanosphere anode, in order to achieve its new results.
A new research paper from the group explained that the new lithium-sulfur battery delivered a specific capacity of ∼750 mAh g–1 over 500 cycles (85% of the initial capacity). The reason for the impressive new results (possibly), according to those involved, is as a result of a synergistic effect between the enhanced electrochemical performance of the new anode and the optimized layout of the cathode.
While the new work won’t result in lithium-sulfur batteries replacing lithium-ion ones tomorrow, it does bring the commercial viability of the technology one step closer — as the new work has addressed some of the primary issues with the technology.
Green Car Congress provides some further information:
The researchers designed a LiS cell using a dual-type hybrid sulfur cathode and a lithiated Si/SiOx nanosphere anode with an optimized liquid electrolyte. The cathode consists of an activated carbon−sulfur composite on a gas diffusion layer (GDL) electrode in contact with a catholyte solution to which Li2S8has been added. This cathode system delivers a maximum capacity of ∼1300 mAh g−1 with respect to the overall mass of sulfur (about 1.2 mg) from both the solid sulfur (about 0.2 mg on the electrode) and the dissolved lithium polysulfide (1.024 mg in 80 μL of the polysulfide-containing electrolyte).
At a rate of C/3, the cathode shows a capacity of ∼1000 mAh g−1; Coulombic efficiencies of more than 99.3% except for the first cycle; and a maintenance of the capacity above 99% of the initial capacity even after 100 cycles. The lithiated Si/SiOx nanosphere anode used shows highly stable cycling behavior over 100 cycles with a capacity of as high as 800 mAh g−1 and cycling efficiency approaching 100%. The full lithium-ion sulfur cell presented in the study delivers a capacity of ∼750 mAh g−1 with an average working voltage of about 1.8 V, corresponding to the energy density of 497 Wh kg−1 based on the weight of active materials on the cathode and anode.
Very interesting. While I personally don’t expect lithium-sulfur batteries to replace lithium-ion batteries anytime in the near future for most applications (and never at all for some applications), the technology does seem to be improving fairly rapidly. It’ll be interesting to see how it ends up being utilized.
The new findings were detailed in a paper published in the journal Nano Letters.
Image Credit: Hanyang University