Homogeneous catalysts have great promise for accelerating the sulfur reduction reaction (SRR) and improving sulfur utilization in Li-S batteries without sacrificing energy density. We report that the d charge of the metal site in metal porphyrin (MTPP) catalysts, which is related to the ligand exchange ability by S species, is linearly correlated to the turn-over frequency (TOF) and apparent activation energy (Ea) in the SRR. MnTPP with a d charge of 1.22 e results in a high TOF of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$37 \, {\rm mol}_{{\rm Li}_{2}{\rm S}} \, {\rm mol}_{\rm metal}^{-1} \, {\rm s}^{-1}$</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mn>37</mn> <mspace width="thinmathspace" /> <msub> <mrow> <mi mathvariant="normal">mol</mi> </mrow> <mrow> <msub> <mrow> <mi mathvariant="normal">Li</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msub> <mrow> <mi mathvariant="normal">S</mi> </mrow> </mrow> </msub> <mspace width="thinmathspace" /> <msubsup> <mrow> <mi mathvariant="normal">mol</mi> </mrow> <mrow> <mi mathvariant="normal">metal</mi> </mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msubsup> <mspace width="thinmathspace" /> <msup> <mrow> <mi mathvariant="normal">s</mi> </mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> for Li2S precipitation. Lithium-sulfur batteries assembled with the MnTPP catalyst had a low shuttle constant of 0.018 h−1, as well as a high reversible capacity of 994 mAh g−1 at 1 C and a stable cycling performance with a low capacity decay per cycle of 0.08% after 500 cycles. This work establishes an electronic structure-activity relationship for porphyrin-based catalysts in SRR and provides a strategy for the design of homogeneous catalysts for Li-S batteries.

Ligand exchange determines the catalytic activity of the sulfur reduction reaction in lithium-sulfur batteries

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发表日期：

2026年5月7日

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Jingyi Wang,
Tongxin Shang,
Yafei Sun,
Qian Yang,
Jiahui Zuo,
Guohua Yao,
Wenzhong Shen,
Linkai Peng,
Wei Lv,
Ying Wan

摘要

Homogeneous catalysts have great promise for accelerating the sulfur reduction reaction (SRR) and improving sulfur utilization in Li-S batteries without sacrificing energy density. We report that the d charge of the metal site in metal porphyrin (MTPP) catalysts, which is related to the ligand exchange ability by S species, is linearly correlated to the turn-over frequency (TOF) and apparent activation energy (E_a) in the SRR. MnTPP with a d charge of 1.22 e results in a high TOF of $37 \, {\rm mol}_{{\rm Li}_{2}{\rm S}} \, {\rm mol}_{\rm metal}^{-1} \, {\rm s}^{-1}$ $37 {mol}_{{Li}_{2} S} {mol}_{metal}^{- 1} s^{- 1}$ for Li₂S precipitation. Lithium-sulfur batteries assembled with the MnTPP catalyst had a low shuttle constant of 0.018 h⁻¹, as well as a high reversible capacity of 994 mAh g⁻¹ at 1 C and a stable cycling performance with a low capacity decay per cycle of 0.08% after 500 cycles. This work establishes an electronic structure-activity relationship for porphyrin-based catalysts in SRR and provides a strategy for the design of homogeneous catalysts for Li-S batteries.