Construction of plum-branch-like CoSe2@N-Doped carbon/carbon fiber with dual protective mechanisms for enhanced lithium storage

Abstract

Cobalt selenide (CoSe₂) emerges as a highly promising anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity and cost-effectiveness. Despite these merits, its practical utilization faces challenges stemming from substantial volume fluctuations and limited electronic conductivity. To tackle these issues, a plum-branch-like structure of CoSe₂@N-doped carbon that embedded in one-dimensional N-doped carbon fibers (CoSe₂@NC/CFs), is successfully synthesized through an in-situ confinement method. Well-defined CoSe₂@NC nanoparticles, featuring diameters between 20∼30 ​nm, are uniformly dispersed on both the inner and outer surfaces of the carbon fibers. The distinctive architecture of CoSe₂@NC/CFs ensures an increased number of active sites, elevated electronic conductivity, alleviated volume expansion, and accelerated reaction kinetics. Consequently, the CoSe₂@NC/CFs exhibits remarkable cycling performance and exceptional rate capability. Operating at a current density of 1000 ​mA ​g⁻¹, the CoSe₂@NC/CFs anode sustains a capacity of 664 ​mA ​h ​g⁻¹ with no obvious capacity decay over 500 cycles. Even at a high current density of 5000 ​mA ​g⁻¹, it maintains a capacity of 445 ​mA ​h g⁻¹ with a mere 0.02 ​% capacity decay per cycle. This study introduces a novel approach to anode material design, showcasing significant advancements in lithium-ion battery technology.