Adaptively Reforming Natural Enzyme to Activate Catalytic Microenvironment for Polysulfide Conversion in Lithium-Sulfur Batteries

Catalyzing polysulfide conversion is a promising way toward accelerating complex and sluggish sulfur redox reactions (SRRs) in lithium-sulfur batteries. Reasonable alteration of an enzyme provides a new means to expand the natural enzyme universe to catalytic reactions in abiotic systems. Herein, we design and fabricate a denatured hemocyanin (DHc) to efficiently catalyze the SRR. After denaturation, the unfolded beta-sheet architectures with exposed rich atomically dispersed Cu, O, and N sites and intermolecular H-bonds are formed in DHc, which not only provides the polysulfides for a strong spatial confinement effect in microenvironment via S-O and Li center dot center dot center dot N interactions but also activates chemical channels for electron/Li+ transport into the Cu active center via H/Li-bonds to catalyze polysulfide conversion. As expected, the charge/discharge kinetics of DHc-containing cathodes is fundamentally improved in cyclability with nearly 100% Coulombic efficiency and capacity even under high sulfur loading (4.3 mg cm-2) and lean-electrolyte (8 mu L mg-1) conditions.

Automated summary

Design and fabrication of denatured hemocyanin (DHc) provides a new approach to catalyzing polysulfide conversion in lithium-sulfur batteries. The unfolded beta-sheet architectures in DHc, along with exposed atomically dispersed Cu, O, and N sites and intermolecular H-bonds, enhance the catalytic activity of DHc for polysulfide conversion. DHc-containing cathodes show improved charge/discharge kinetics and high stability in cyclability even under high sulfur loading and lean-electrolyte conditions.