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Cathode-Confined Polysulfide Retention-Release Reprograms Li 2 S Deposition in High-Loading Li–S Batteries

Lee, Seungmin [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000088097780)·Tan, Sha [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:000000018277893X)·Zhang, Xiaohu [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000892831229)·Wierzbicki, Dominik [Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)]·Shi, Lili [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]·Anderson, Cassidy [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]·Lu, Dongping [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]·Hu, Enyuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000218814534)
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Abstract

High-loading lithium-sulfur (Li-S) cells operated with lean electrolyte are limited by polysulfide crossover to Li metal and by transport-limited liquid-solid conversion that forms passivating Li 2 S films. Here, we show that a cathode-facing separator coating of carboxylated multiwalled carbon nanotubes acts as a cathode-confined polysulfide reservoir with intermediate binding. Early in discharge it captures newly generated polysulfides at the separator interface, suppressing shuttle reactions. As polysulfides are consumed, the reservoir buffers concentration gradients and feeds reactants back to the cathode, shifting Li 2 S deposition from burst-like film growth to progressive, three-dimensional, porous formation. Synchrotron XRD and S K-edge XANES, together with Scharifker–Hills nucleation analysis and depth-of-discharge EIS/DRT, substantiate this coupled transport–reaction control. With 4.3 mg S cm -2 and E/S = 5, cells reach 4.2 mAh cm -2 and retain 90% capacity over 100 cycles at 20 °C.

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Lee, Seungmin [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000088097780), Tan, Sha [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:000000018277893X), Zhang, Xiaohu [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000892831229), Wierzbicki, Dominik [Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)], Shi, Lili [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)], Anderson, Cassidy [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)], Lu, Dongping [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)], Hu, Enyuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000218814534). 2026-04-28. Cathode-Confined Polysulfide Retention-Release Reprograms Li 2 S Deposition in High-Loading Li–S Batteries. https://doi.org/10.1021/acsenergylett.6c00653

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