VOPO4 as effective long-chain polysulfides adsorbent for lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries have aroused increasing interest and are gradually becoming a promising next-generation energy storage system. However, low electronic conductivity and shuttle effect of lithium polysulfides (LiPSs) severely hindered their commercial applications. To address the issues effectively, herein, a transition metal phosphate-VOPO4 was introduced into Li–S battery cathode, supplemented with carbon nanotubes (CNTs) as a conductive agent. Density functional theory method revealed that VOPO4 has strong polysulfides anchoring due to high abundant polar active site, which improved the electrochemical performances of sulfur cathode. At 0.5 C, the S/(VOPO4 + CNTs) electrode presents a discharge capacity of up to 912.8 mAh g−1 after 500 cycles. Even at 2 C, it also kept stable at 623.8 mAh g−1 after 800 cycles. The results showed that VOPO4 provided a helpful reference to have effectively expanded the applications and promoted the performance of Li–S batteries.