Three-dimensional porous carbon decorated with FeS2 nanospheres as electrode material for electrochemical energy storage

Abstract

The large volume variation and decomposition of pyrite iron sulfide (FeS2) during the charge/discharge process are still a big issue limiting its application as electrode material for electrochemical energy storage. Herein, three-dimensional porous carbon (3DPC) decorated with FeS2 nanospheres nanocomposites (FeS2/3DPC) are developed as electrode material for supercapacitors and sodium ion batteries (SIBs) through a facile hydrothermal approach. The FeS2/3DPC nanocomposites demonstrate much better electrochemical energy storage performances than pure FeS2. The 50 %FeS2/3DPC (FeS2 content at 50% weight percent) shows an outstanding specific capacitance of 304F g−1 at 2 A g−1. Moreover, the 50 %FeS2/3DPC as anode for Na+/Na half cell presents a high specific capacity of 770.3 mAh g−1 at 0.02 A g−1, and shows a remarkable rate performance and cyclic stability. The results prove that 3DPC as FeS2 substrate can not only improve the conductivity of electrode material, but also effectively inhibit the volume collapse of FeS2. The as-designed embedded structure and the synthesis technology should have a promising prospect for applying in electrochemical energy storage.