Polypyrrole Coated Al-TDC Composite Structure as Lithium-Sulfur Batteries Cathode

Due to the high theoretical capacity of sulfur (1675 $$ mAh $$ g − 1 ) ${\text{g}}^{-1})$ , low cost and environmental friendliness, lithium-sulfur batteries have shown broad prospects in future energy conversion and storage systems. However, the shuttle effect and insulating properties of sulfur restrict its practical application. Herein, we report a facile approach to fabricate Al-TDC@S-PPy composite material as lithium-sulfur battery electrode. In this strategy, a topological porous Al-TDC ( TDC = 2 $\mathrm{\text{TDC}}=2$ ,5-thiophenedicarboxylate) with 8-connected clusters is reported, which can provide strong adsorption for dissolved intermediate polysulfides and alleviate volume expansion. Meanwhile, Polypyrrole, (PPy) as a conductive and flexible additive to expedite electron transport, improves electrical conductivity. Consequently, the Al-TDC@S-PPy composite cathode exhibits a higher initial specific capacity (1310.4 $$ mAh $$ g − 1 ${\text{g}}^{-1}$ at 0.2 $$ C). The final reversible capacity is 411.0 $$ mAh $$ g − 1 ${\text{g}}^{-1}$ after 200 cycles at 1 C. We can extend this strategy to other metal-organic frameworks (MOFs) and manufacture MOF/conductive polymer composite electrodes for high-performance lithium-sulfur batteries.