MOF-5-derived honeycomb structured mesoporous carbon with AlF 3 ·3H 2 O for high-stability lithium-sulfur battery cathode

Lithium-sulfur (Li–S) battery has now gradually emerged as the representative secondary energy storage battery of low cost, high security, and high theoretical specific capacity (1675 mAh g −1 ). However, the insulation properties of sulfur and shuttle issue of polysulfides between electrolytes lead to poor coulombic efficiency and performance of sulfur cathode. Therefore, we use metal–organic frameworks (MOFs) as pore-forming agent and glucose as primary carbon source to synthesize a honeycomb structured porous carbon (PC) material with high specific surface area (2151.9 m 2 g −1 ) and large mesopore volume (2.16 cm 3 g −1 ), which acts as the conductive skeleton for sulfur cathode. Furthermore, after mixing a trace of aluminum fluoride (AlF 3 ) into sulfur electrode, the corresponding cycle performance and electrochemical stability have been further improved. The AlF 3 ·3H 2 O/PC/S composition with 80 wt% sulfur loading exhibits the highest discharge capacity of 1298.1 mAh g −1 at the current density of 1 C and maintains at 455.6 mAh g −1 with ~ 99% coulombic efficiency after 500 cycles. This work supplies a facile and effective strategy for manufacture of more progressive porous carbonaceous sulfur host material and improving practical performance of Li–S batteries.