Sulfur double encapsulated in a porous hollow carbon aerogel with interconnected micropores for advanced lithium-sulfur batteries

Abstract

Abstract Due to high theoretical specific capacity, energy density, and low-cost lithium-sulfur (Li-S) batteries became the most potential energy storage devices for the next generation. The harsh shuttling effect, poor electroconductibility of sulfur, and volume change affect the Li-S battery’s practical application. Herein, the rational design of porous hollow carbon aerogel (PHCA) with an ultra-high specific surface area of 2054.5 m2 g−1 and outstanding adsorption ability is firstly fabricated to restrict the shuttling effect of lithium polysulfides (LiPSs) by using commercialized nano-CaCO3 as a template. As a sulfur host, the S/PHCA cathode delivers initially discharge specific capacity of 992.7 mAh g−1 with an average Coulombic efficiency of 97.6%. After 200 cycles, it obtains the reversible specific capacities of 600.1 mAh g−1 for S/PHCA cathode at 0.1C (2.2 mg cm−2) corresponding to 60.45% of their initial discharge specific capacity. As a PHCA interlayer, the Li-S battery with the PHCA interlayer exhibits initially discharge specific capacity of 1267.7 mAh g−1 with an average Coulombic efficiency of 99.36% at 0.1C (3.2 mg cm−2) and maintains at 863.3 mAh g−1 with the discharge specific capacity retention rate of 69.2%. This is an effective strategy to improve the outstanding electrochemical performance which is beyond reported carbon materials, which is attributed to stronger adsorption of LiPSs by the micropore. This work provides a new direction for the modification of a sulfur host and interlayer and simultaneously reveals the relationship between the heteroatom distribution and LiPSs.