3D interconnected structure-based lithium–sulfur batteries with high energy densities

Abstract

Lithium–sulfur (Li–S) batteries have attracted extensive attention as competitive candidates for next-generation high-energy–density batteries because of their excellent theoretical energy density, and the abundance and low cost of sulfur. In this study, a high-energy–density Li–S battery based on a porous metal–carbon composite cathode with a three-dimensional (3D) structure and high sulfur loading, and a metal sponge skeleton–Li composite anode was fabricated. The 3D metal composite electrodes provided a highly robust conductive pathway that improved the electrical/ionic transport. In particular, the 3D sponge–Li anode exhibited stable stripping and plating performance in symmetric cell tests owing to the high electron conductivity provided by the interconnected metal networks. In addition, well-designed full cells with 3D Al–multi-walled carbon nanotube on sulfur cathodes and 3D Ni sponge/Li anodes demonstrated excellent electrochemical performance owing to their high sulfur loading (>8 mg cm−2). The weight of the anode was reduced to less than half of that of a typical Li anode. Further, the cell exhibited an excellent rate capability and improved cyclability. Therefore, our 3D interconnected structure can effectively achieve high sulfur loading and energy densities, thereby addressing the limitations of conventional Li–S cells and achieving notable advances in electrochemical energy storage.