High sulfur loaded carbon aerogel cathode for lithium–sulfur batteries

Abstract

An attempt made to improve sulfur loading in a template free porous carbon to the extent of 70 wt. % has inferred two interesting observations, viz., 60 wt. % sulfur loading exhibits superior electrochemical properties in the S@C composite form and an enhanced 73 wt. % sulfur loading leads to the formation-cum-stabilisation of sulfur in its monoclinic phase. Carbon aerogel with tunable properties, derived from the catalyst aided cross linki ng of resorcinol and formaldehyde, possessing a specific surface area of 1395 m 2 /g and pore volume of 1.423 cm 3 /g has been exploited for sulfur loading to form series of S@C composites. Interestingly, carbon aerogel prepared in the present study offers multifarious advantages such as conducting additive, potential host to accommodate higher concentration of sulfur and better polysulfide confining matrix. The 60 wt. % sulfur loaded carbon aerogel composite exhibits an appreciable specific capacity of 600 mAh/g at C/10 rate up to 100 cycles, 480 mAh/g at 1C and 422 mAh/g at 2C rate. Hence, the capability of carbon aerogel, synthesized through the present study in accommodating higher concentration of sulfur, effective management of polysulfide shuttle and provision of favorable electrode-electrolyte interface to facilitate extended cycling possibilities at different current densities has been demonstrated.

Hierarchical Porous Carbon Cathode for Lithium–Sulfur Batteries Using Carbon Derived from Hybrid Materials Synthesized by Twin Polymerization

“…After 200th cycles, the charge transfer impedance of PSSO 3 H‐Spiro40_C/S reached to only 27.24 Ω, whereas for the PSSO 3 H‐Spiro50_C/S , it increased to 44.67 Ω. This behavior might have occurred due to higher amount of polysulfide dissolution for the latter with prolonged cycles . This also increases the electrolyte viscosity and restricts the transport of Li + ions through the electrolyte.…”

“…In designing so, the aim is to retain the intermediate polysulfides in the cathode side to gain maximum active mass utilization. Several carbon materials have been reported so far, for example, acetylene black, ketjen black, multiwalled carbon nanotubes (CNTs), carbon aerogels, ordered mesoporous carbon, hydrothermal carbon derived from carbohydrates, onion like carbon as sulfur host, graphene and its derivatives, activated carbon fiber cloths, etc. Jin et al reported high active mass utilization and excellent cycle stability by confining small CNTs inside large CNTs and using this material for embedding sulfur .…”

Mesoporous hollow carbon spheres for lithium–sulfur batteries: distribution of sulfur and electrochemical performance

“…For carbon/sulfur composites with sulfur contents below 60 wt %, the characteristic bands resulting from the vibrations of S 8 cannot be observed, while they are visible at least in some of the composites containing more than 60 wt % sulfur. This behavior has also been reported in the literature [41–43] but could not yet be explained satisfactorily. However, as these observations are in good agreement with the results from pXRD, it can be assumed, that the lack of Raman bands might also be due to confinement effects.…”

Facile Carbon Fluoride/Sulfur Hybrid Cathode for High‐Rate Lithium Batteries

“…The (002) reflection at around 26.5° nearly disappeared, probably due to the high level of fluorination or the crinkled structure with poor regularity along the stacking direction . The decrease in intensity of CF x peaks also shows a well dispersed state of sulfur in hybrid CF x /S materials . Crystalline peaks of sulfur indicate the fddd orthorhombic structure which match the typical pattern PDS N08‐0247.…”

“…Thermogravimetry analysis was carried out to estimate the content of sulfur and fluorine as shown in Figure S2. All curves display two distinct weight loss processes corresponding to the evaporation of sulfur in the range of 190–300 °C and the detachment of fluoride from about 400 to 660 °C . The amount of sulfur in FGR/S, FGF/S, and FCF/S is estimated to be 29.5 wt%, 26.3 wt%, and 29.4 wt%, respectively.…”