Ultradispersed titanium dioxide nanoparticles embedded in a three-dimensional graphene aerogel for high performance sulfur cathodes

Abstract

Lithium-sulfur (Li-S) batteries are regarded as one of the most promising energy storage technologies, however, their practical application is greatly limited by a series of sulfur cathode challenges such as the notorious "shuttle effect", low conductivity and large volume change. Here, we develop a facile hydrothermal method for the large scale synthesis of sulfur hosts consisting of three-dimensional graphene aerogel with tiny TiO2 nanoparticles (5-10 nm) uniformly dispersed on the graphene sheet (GA-TiO2). The obtained GA-TiO2 composites have a high surface area of ∼360 m2 g-1 and a hierarchical porous structure, which facilitates the encapsulation of sulfur in the carbon matrix. The resultant GA-TiO2/S composites exhibit a high initial discharge capacity of 810 mA h g-1 with an ultralow capacity fading of 0.054% per cycle over 700 cycles at 2C, and a high rate (5C) performance (396 mA h g-1). Such architecture design paves a new way to synthesize well-defined sulfur hosts to tackle the challenges for high performance Li-S batteries.