A MOF-derived self-template strategy toward cobalt phosphide electrodes with ultralong cycle life and high capacity

Abstract

Phosphides have high theoretical capacity and low redox voltage, and thus could be favorable for lithium storage. Still, huge volume changes and low electroconductivity hinder their application as the anode materials in lithium-ion batteries. Here, cobalt phosphide nanoparticles encapsulated in a nitrogen-doped carbon matrix by using metal–organic frameworks (ZIF-67) as a self-template have been successfully synthesized and showed excellent electrochemical performance as an anode material for lithium-ion batteries. Cobalt-phosphide-based nanohybrids with different phases can be tailored by accurately controlling the pyrolysis temperature. Electrochemical measurements reveal that the electrochemical performance is closely related to the material phase, and Co_xP-NC-800 nanohybrids with two phases exhibit an ultralong cycle life of 1800 cycles at a current density of 1 A g⁻¹. And a high reversible specific capacity of 1224 mA h g⁻¹ could be delivered after 100 cycles at a current density of 0.1 A g⁻¹.