Facile preparation of ultrafine Ti4O7 nanoparticle-embedded porous carbon for high areal capacity lithium-sulfur batteries

Lithium-sulfur batteries have been investigated as promising energy storage systems due to their high energy density of 2600 W h kg(-1). Although various materials as sulfur hosts can improve the performance of lithium-sulfur batteries, expensive raw materials, complex synthesis and lower sulfur loading impede their practical application. Herein, ultrafine Ti4O7 nanoparticle-embedded porous carbon (PC@Ti4O7) as an efficient sulfur host was facilely prepared using commercial TiO2 nanoparticles and phenolic resin. In this strategy, the highly conductive ultrafine Ti4O7 nanoparticles with abundant active adsorption sites can efficiently trap polysulfides and accelerate their conversion. In addition, the size of the Ti4O7 nanoparticles, depending on the commercial TiO2 nanoparticles, could be easily controlled. Moreover, the sufficient interspaces around the Ti4O7 nanoparticles are beneficial for maximizing the confinement of polysulfides. The hybrid cathode exhibits excellent cycling stability at a high rate of 4C over 1000 cycles. Particularly, the electrode with a sulfur loading of up to 15.6 mg cm(-2) retains an ultrahigh areal capacity of 8.6 mA h cm(-2) at 0.3C over 100 cycles. The low-cost and facile preparation of the PC@Ti4O7 composite provides new insight for the practical application of lithium-sulfur batteries.