A fundamental look at electrocatalytic sulfur reduction reaction

DOI: 10.1038/s41929-020-0498-x

Authors: Lele Peng (University of California, Los Angeles) , Ziyang Wei (University of California, Los Angeles) , Chengzhang Wan (University of California, Los Angeles) , Jing Lin (University of California, Los Angeles) , Zhuo Chen (University of California, Los Angeles) , Dan Zhu (University of California, Los Angeles) , Daniel Baumann (University of California, Los Angeles) , Haotian Liu (University of California, Los Angeles) , Christopher S. Allen (University of Oxford; Diamond Light Source) , Xiang Xu (University of California, Los Angeles) , Angus I. Kirkland (University of Oxford; Diamond Light Source) , Imran Shakir (University of California, Los Angeles; King Saud University) , Zeyad Almutairi (King Saud University) , Sarah Tolbert (University of California, Los Angeles) , Bruce Dunn (University of California, Los Angeles) , Yu Huang (University of California, Los Angeles) , Philippe Sautet (University of California, Los Angeles) , Xiangfeng Duan (University of California, Los Angeles)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Catalysis , VOL 3 , PAGES 762 - 770

State: Published (Approved)
Published: September 2020
Diamond Proposal Number(s): 23956

Abstract: The fundamental kinetics of the electrocatalytic sulfur reduction reaction (SRR), a complex 16-electron conversion process in lithium–sulfur batteries, is so far insufficiently explored. Here, by directly profiling the activation energies in the multistep SRR, we reveal that the initial reduction of sulfur to the soluble polysulfides is relatively easy owing to the low activation energy, whereas the subsequent conversion of the polysulfides into the insoluble Li2S2/Li2S has a much higher activation energy, contributing to the accumulation of polysulfides and exacerbating the polysulfide shuttling effect. We use heteroatom-doped graphene as a model system to explore electrocatalytic SRR. We show that nitrogen and sulfur dual-doped graphene considerably reduces the activation energy to improve SRR kinetics. Density functional calculations confirm that the doping tunes the p-band centre of the active carbons for an optimal adsorption strength of intermediates and electroactivity. This study establishes electrocatalysis as a promising pathway to tackle the fundamental challenges facing lithium–sulfur batteries.

Journal Keywords: Batteries; Electrocatalysis

Subject Areas: Chemistry, Energy

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E02-JEM ARM 300CF