A Novel Synthesis of Vse2 as a High-Rate Lithium-Ion Battery Anode Material

Abstract

VSe2 is a promising anode material for Li-ion battery due to its unique layered structure, and its metallic properties. However, further exploration to investigate the lithium storage performance of VSe2 is limited by the synthesis difficulty of pure VSe2. In this work, a novel nitrogen-doped carbon modified VSe2 obtained by using p-phenylenediamine as the reducing agent is reported. This material delivers a reversible capacity of 738.25 mA h g-1 at 100 mA g-1 and after 50 cycles, it retains 772.15 mA h g-1. Using p-phenylenediamine as a reducing agent to obtain VSe2 is demonstrated for the first time, and p-phenylenediamine also provides carbon and nitrogen sources for the heteroatom modification of VSe2. This modification of nitrogen-doped carbon facilitates the generation of new active sites, and improve charge transfer. First-principle calculations show that the diffusion barrier for the Li+ migration within the VSe2 layers is low. The ex-situ XRD results verify that VSe2 stores lithium through intercalation and conversion reactions. This work may provide a new solution for synthesizing high-performance transition metal dichalcogenide electrode materials.

Keywords: VSe2, P-phenylenediamine, LIBs, active sites, charge transfer