Bamboo-structured N-doped CNTs/FeF3·0.33H2O derived from melamine as a high-performance cathode for Li-ion batteries

Abstract

FeF₃·0.33H₂O with a special one-dimension tunnel structure has been considered as a potential cathode material. However, the low electron conductivity of FeF₃·0.33H₂O prevents its practical application. FeF₃·0.33H₂O coupled with a carbon material is an effective method to solve the low electric conductivity of FeF₃·0.33H₂O. Hence, we apply a facile approach using the catalyzed pyrolysis of melamine and a fluorination–annealing process to synthesize the N-doped CNTs/FeF₃·0.33H₂O composite with a bamboo-like morphology. The as-prepared composite displays a good cycling performance with a reversible discharge capacity of 160.7 mA h g⁻¹ at 40 mA g⁻¹ after 100 cycles and a good rate performance, as well as a good electrochemical performance even at a relatively high mass loading. The good electrochemical properties can be mainly ascribed to the fact that N-doped CNTs play the role of a cross-linked conductive network to provide an electron-transport expressway in the active material. This simple catalyzed pyrolysis and fluorination–annealing approach provides a promising avenue for the application of iron fluoride as a cathode material.