Construction of Tubular Polypyrrole-Wrapped Biomass-Derived Carbon Nanospheres as Cathode Materials for Lithium–Sulfur Batteries

A promising hybrid material composed of tubular polypyrrole (T-PPy)-wrapped monodisperse biomass-derived carbon nanospheres (BCSs) was first synthesized successfully via a simple hydrothermal approach by using watermelon juice as the carbon source, and further used as an anchoring object for sulfur (S) of lithium–sulfur (Li–S) batteries. The use of BCSs with hydrophilic nature as a framework could provide large interface areas between the active materials and electrolyte, and improve the dispersion of T-PPy, which could help in the active material utilization. As a result, BCS@T-PPy/S as a cathode material exhibited a high capacity of 1143.6 mA h g−1 and delivered a stable capacity up to 685.8 mA h g−1 after 500 cycles at 0.5 C, demonstrating its promising application for rechargeable Li–S batteries.