Despite the outstanding gravimetric performance of lithium–sulfur (Li–S) batteries, their practical volumetric energy density is normally lower than that of lithium-ion batteries, mainly due to the low density of nanostructured sulfur as well as the porous carbon hosts. Here, a novel approach is developed to fabricate high-density graphene bulk materials with “ink-bottle-like” mesopores by phosphoric acid (H3PO4) activation. These pores can effectively confine the polysulfides due to their unique structure with a wide body and narrow neck, which shows only a 0.05% capacity fade per cycle for 500 cycles (75% capacity retention) for accommodating polysulfides. With a density of 1.16 g cm−3, a hybrid cathode containing 54 wt% sulfur delivers a high volumetric capacity of 653 mA h cm−3. As a result, a device-level volumetric energy density as high as 408 W h L−1 is achieved with a cathode thickness of 100 µm. This is a periodic yet practical advance to improve the volumetric performance of Li–S batteries from a device perspective. This work suggests a design principle for the real use Li–S batteries although there is a long way ahead to bridge the gap between Li–S batteries and Li–ion batteries in volumetric performance.
- graphene monolith
- ink-bottle-like pores
- lithium–polysulfide batteries
- volumetric performance
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)