Metal–Organic Framework-Derived Sea-Cucumber-like FeS₂@C Nanorods with Outstanding Pseudocapacitive Na-Ion Storage Properties

Sodium-ion batteries (SIBs) are supposed to be attractive energy strorage and supply devices due to the abundant reserves of sodium. Their limited specific capacity and rate capacity, however, are standing in the way of the extensive application of SIBs. It is reported herein that porous sea-cucumber-like FeS₂@C nanorods can act as efficient cathode materials to satisfy the rigorous requirements of the proposed applications. The fabrication of the sea-cucumber-like FeS₂@C nanorods involves the hydrothermal growth of F-MIL (where F = Fe, MIL = materials from the Lavoisier Institute) nanorods, and subsequent sulfidation. The electrochemical results demonstrate that the FeS₂@C nanorods are an outstanding cathode material for SIBs with high specific capacity (385 mAh/g), ultralong lifetime (160 mAh/g after 10 000 cycles at 20 A/g), and exceptional rate capability. The metal–organic framework (MOF) template method provides a useful route toward the development of high-performance electrode materials with robust power and cyclability.