Selenium Encapsulated into Interconnected Polymer-Derived Porous Carbon Nanofiber Webs as Cathode Materials for Lithium-Selenium Batteries

Abstract

Interconnected porous carbon nanofiber webs (PCNFWs) cross-linked fibers, which were carbonized from polypyrrole (PPy) nanofibers and activated with KOH, were prepared as improved carbon matrix for encapsulating selenium for lithium-selenium batteries. The prepared interconnected porous carbon nanofiber webs/selenium (PCNFW/Se) composites showed an obvious cross-linked structure and selenium homogeneously distributed in the PCNFWs. The PCNFW/Se composite as cathode material delivered an initial discharge capacity of 563.9 mAh g−1 with a reversible capacity of 414.5 mAh g−1 retained after 100 cycles at 0.2 C (135 mA g−1) rate. Even at a current density of 1 C (675 mA g−1), the composite still exhibited an initial discharge capacity of 439 mAh g−1 and retained 323.7 mAh g−1 after 300 cycle. The high cycling stability and excellent rate cyclability demonstrated that combining the favorable aspects of interconnected porous nanostructure, abundant channel structure and high specific surface area is an effective way to improve the electrochemical performance of the carbon/selenium cathodes for lithium-selenium batteries.