Highly symmetric gigaporous carbon microsphere as conductive host for sulfur to achieve high areal capacity for lithium-sulfur batteries
Abstract
We propose a gigaporous carbon microsphere, given its large surface area and high porosity, as a novel host for sulfur infusion and a potential cathode active material for Li-S batteries. Because the infused sulfur is distributed and confined in the three-dimensional, connected carbon network of the porous microsphere, an electrode made of this material shows very high conductivity. In addition, as the synthesized carbon microsphere is polar and a good adsorbent for polar polysulfides, it improves battery performance by reducing loss of sulfur and suppressing the shuttle effect. The battery constructed using this material shows high cell performance with a highly stable capacity at ~1000 mAh g-1 under a charge/discharge current of 0.2C for 200 cycles and a Coulombic efficiency of 100%. After 200 charge/discharge cycles the electrode retains good structural integrity, which is an important cause for the insignificant increase in the ionic and electronic impedances of the battery. Moreover, a simple increase in the sulfur loading of the electrode to 6 mg cm-2 with the addition of electrolyte in a moderate electrolyte/sulfur ratio of 5 μL mg-1 can effectively achieve a practical areal capacity > 3-4 mAh cm-2 at 0.1-0.3C.
- Publication:
-
Journal of Power Sources
- Pub Date:
- March 2020
- DOI:
- 10.1016/j.jpowsour.2020.227818
- Bibcode:
- 2020JPS...45127818C
- Keywords:
-
- Li-S battery;
- Porous microsphere;
- Cathode;
- Areal capacity