Sn Nanoparticles Encapsulated in Nanoporous Nitrogen-Rich Carbon Derived from Sn-MOF@ZIF-8 for Lithium–Sulfur Battery Separators

Lithium–sulfur batteries (LSBs) have attracted considerable attention as high-energy density battery technology for applications in renewable energy storage and electric vehicles. However, challenges such as low sulfur conductivity and the polysulfide shuttle effect must be addressed. In this study, we prepared C–N/Sn with nanoporous channels using Sn-MOF@ZIF-8 as a precursor. The resulting C–N/Sn material has highly dispersed Sn nanoparticles encapsulated in nitrogen-rich carbon with a three-dimensional continuous conducting framework. During the preparation process, tin oxides were reduced to elemental Sn nanoparticles, while the decomposition of the ZIF-8 skeleton and the volatilization of most of the Zn resulted in the formation of nanoporous channels, which facilitates the transport of Li ions and electrons while inhibiting polysulfide shuttling. The C–N/Sn separator battery exhibited an initial discharge specific capacity of 925 mAhg–1 at a sulfur loading of 2.8 mg cm–2 and 0.5 C current density, which remained at 515 mAh g–1 after 500 cycles. Furthermore, it also demonstrated good cycling performance at a higher sulfur loading condition of 5 mg cm–2, highlighting its potential for commercialization.