Integrating solid interfaces for catalysis in all-solid-state lithium–sulfur batteries†

Abstract

All-solid-state lithium–sulfur batteries (ASSLSBs) hold great promise for achieving high energy densities. However, their practical applications are hindered by low sulfur utilization and limited cycle life attributed to the sluggish sulfur reaction kinetics. Although catalysis is an effective way to address kinetic limitations, it often becomes ineffective because solid contact between the catalyst and the sulfur species cannot form the molecular-level interfaces necessary for catalytic reactions. Here, we propose a micropore confining and fusing strategy to integrate the catalysis reaction interfaces on a molecule-level. The prepared microporous carbon sheet confines the small molecule sulfur and catalyst clusters in its sub-2 nm micropores, enabling the formation of integrated sulfur-catalyst-carbon interfaces, which fundamentally achieves a molecular-scale contact for solid catalysis and eliminate the interfacial mismatches in the solid cathodes. Such interfaces significantly enhance the sulfur reaction kinetics and utilization even at high rates. Moreover, the large micropore volume (2.0 cm³ g⁻¹) accommodates the substantial volume changes of sulfur, stabilizing interparticle interfaces both within the cathode and at the cathode/electrolyte interface and finally enabling exceptional cycling stability. The assembled battery shows a remarkable specific capacity of over 1000 mA h g⁻¹ at 1.0C and retains over 85% capacity after 1400 cycles, both among the highest ever reported. The interface engineering proposed in this study offers a practical route for ASSLSB applications.