There has been tremendous progress in enhancing the electrochemical performance of lithium-sulfur batteries. For example, the use of dissolved polysulfide (PS) as cathode improves sulfur (S) utilization and redox kinetics. Notably, free-standing PS cathodes have exceptional performance, but their preparation is not scalable as compared to the slurry-coating process. However, the electrochemical performance of slurry-coated PS electrodes such as Pt/graphene, Super P, metal nitrides and hierarchical porous carbon, is not satisfactory. Herein, a high-performance lithium-PS battery using inexpensive commercially available materials has been developed. Specific capacities between 1220 and 1007 mAh g−1 were achieved at charge rates of 0.2–2.0 C, having capacity fade of lower than 0.14% per cycle over 200 cycles. At higher S loading, a practical areal capacity of > 4 mAh cm-2 was achieved. The difference between PS and melt-diffusion S cathodes was also examined. Remarkably, the PS cathode offered 48% higher specific capacity and 26% lower capacity fade than the melt-diffused S thode due to differences in morphology, surface area and ohmic resistance of the cathodes. This work provides a strong case towards a paradigm shift away from conventional cathode preparation approaches to improve the electrochemical performance of lithium-S batteries.
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http://creativecommons.org/licenses/by-nc-nd/4.0/
Funding Info:
This research is supported by core funding from NanoBio Lab.