Carbon Nanofoam Papers as Electrode Architectures for Chalcogens in Lithium- and Sodium-Based Batteries

Sulfur has emerged as a promising charge-storage material for advanced rechargeable batteries based on the high capacity of the sulfur/sulfide redox reaction and earth-abundance of this element. The main limitations of sulfur-containing electrodes are the poor conductivity of sulfur and the propensity for release of soluble polysulfides into the electrolyte during redox cycling. These challenges can be mitigated by incorporating sulfur into porous, conductive carbon substrates to form cathodes for nonaqueous lithium- and sodium-based batteries. We find that carbon nanofoam papers (CNFPs) are highly effective materials for such purposes, providing the advantages of tunable pore size distributions (nm to µm), scalability in area (many cm²) and thickness (100s of µm), and plug-and-play form factors for efficient battery construction [1]. Vapor deposition is a convenient route to coat the interior and exterior surfaces of CNFPs with nanometers-thick sulfur at effective weight loadings of up to 60 %; selenium and sulfur–selenium blends are also deposited in a similar fashion. We investigate the interplay of CNFP structure and chalcogen loading and composition with electrochemical performance in coin cells and pouch cells. In situ characterization with such techniques as optical microscopy and X-ray absorption spectroscopy provides additional details on redox mechanisms and associated side reactions.<br/><br/>1. Z. G. Neale, M. J. Lefler, J. W. Long, D.R. Rolison, M. B. Sassin, and R. E. Carter, <i>Nanoscale</i> (2023) in the press (DOI: 10.1039/D3NR02699J).