Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published July 23, 2014 | Supplemental Material
Journal Article Open

Sulfur-Functionalized Mesoporous Carbons as Sulfur Hosts in Li–S Batteries: Increasing the Affinity of Polysulfide Intermediates to Enhance Performance

Abstract

The Li–S system offers a tantalizing battery for electric vehicles and renewable energy storage due to its high theoretical capacity of 1675 mAh g^(–1) and its employment of abundant and available materials. One major challenge in this system stems from the formation of soluble polysulfides during the reduction of S_8, the active cathode material, during discharge. The ability to deploy this system hinges on the ability to control the behavior of these polysulfides by containing them in the cathode and allowing for further redox. Here, we exploit the high surface areas and good electrical conductivity of mesoporous carbons (MC) to achieve high sulfur utilization while functionalizing the MC with sulfur (S–MC) in order to modify the surface chemistry and attract polysulfides to the carbon material. S–MC materials show enhanced capacity and cyclability trending as a function of sulfur functionality, specifically a 50% enhancement in discharge capacity is observed at high cycles (60–100 cycles). Impedance spectroscopy suggests that the S-MC materials exhibit a lower charge-transfer resistance compared with MC materials which allows for more efficient electrochemistry with species in solution at the cathode. Isothermal titration calorimetry shows that the change in surface chemistry from unfunctionalized to S-functionalized carbons results in an increased affinity of the polysulfide intermediates for the S–MC materials, which is the likely cause for enhanced cyclability.

Additional Information

© 2014 American Chemical Society. Received: November 14, 2013. Accepted: February 4, 2014. Published: February 13, 2014. Special Issue: New Materials and Approaches for Electrochemical Storage We thank Georges Paradis and William Clinton for assistance with CHN analysis and ^(34)S isotope analysis. We thank Dr. Tomohiro Kawai of Mitsubishi Chemical for helpful discussions on electrochemical methods. Fellowship support to KAS from the ConvEne IGERT Program of the National Science Foundation (DGE 0801627) is gratefully acknowledged. This research made extensive use of the shared experimental facilities of the Materials Research Laboratory (MRL). The MRL Shared Experimental Facilities are supported by the MRSEC Program of the NSF under Award DMR 1121053; a member of the NSF-funded Materials Research Facilities Network (www.mrfn.org).

Attached Files

Supplemental Material - am405025n_si_001.pdf

Files

am405025n_si_001.pdf
Files (124.2 kB)
Name Size Download all
md5:e7c7872a6ad18407577e04e15ecd4573
124.2 kB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023