화학공학소재연구정보센터
Journal of Power Sources, Vol.442, 2019
From rational construction to theoretical study: Li3V2(PO4)(3) nanoplates with exposed {100} facets for achieving highly stable lithium storage
The polyanionic cathodes with high safety and appropriate redox potential, attract tremendous attention for Li-ion batteries. However, their high-rate cycling stability and poor industrial feasibility still remain great challenges. Herein, Li3V2(PO4)(3) nanoplates with dominate {100} exposed facets embedded in a N-doped carbon matrix are successfully constructed. The in-situ dispersion-chelating approach benefits from reductive hydrogen peroxide and polyacrylamide, which acts as a strong ligand that coordinates the precursors to the polymer chains, resulting in a desirable construction of a highly porous structure (surface area: 69.667 m(2) g(-1)) with homogeneous carbon coating, and thus facilitating structural stability. Therefore, the designed Li3V2(PO4)(3)/C composite displays competitive capacities with outstanding cycle stabilities (95.8% retention after 500 cycles at 1C rate and 89.1% after 2000 cycles at 20C rate) under both two and three electron exchange conditions. Moreover, theoretical studies are applied to explore the origin of enhanced kinetics. The molecular dynamics simulations demonstrate an anisotropic Li+ diffusion with a fast [100]-oriented diffusion channel. The first-principles calculations reveal that the architecture induced by defect carbon can provide better interfacial stability and electronic conductive medium. This developed strategy combined with mechanism study provides an exciting perspective and avenue for establishing more-efficient electrode materials.