Sea-urchin-like iron-cobalt phosphide as an advanced anode material for lithium ion batteries

Abstract

Lithium-ion batteries (LIBs) are the most advanced and well-developed renewable energy storage solutions over the last three decades. Resourceful and cost-effective transition metal phosphides (TMPs) have gained immense attention for various energy storage devices due to their excellent electrochemical properties. Here, we report a bimetallic phosphide (iron-cobalt phosphide, FeCoP) synthesized by a simple hydrothermal method followed by a low-temperature phosphorization. We have used this material as the anode for LIBs with lithium foil as the counter and reference and 1 M lithium hexafluorophosphate (LiPF₆) in a mixture of EC : DMC (1 : 1) as the electrolyte. The electrochemical tests reveal that the device exhibited an excellent discharge capacity of 1653.4 mA h g⁻¹ at a current density of 100 mA g⁻¹. The device retained about 80% of its performance even after 1000 cycles at a current density of 5 A g⁻¹. The performance of the synthesized material shows that TMPs are of great use for the application of LIBs.