One-dimensional coaxial cable-like MWCNTs/SnP@C as an anode material with long-term durability for lithium ion batteries

High capacity Sn 4 P 3 is considered as a promising anode candidate for lithium-ion batteries (LIBs), but the fast capacity decay caused by the enormous volume changes and tin agglomeration during cycling largely limits its practical applications. Herein, MWCNTs/Sn 4 P 3 @C with a coaxial cable-like structure is designed, where a carbon protective layer is wrapped on the surfaces of Sn 4 P 3 nanoparticles to minimize their exposure to the electrolyte and multi-walled carbon nanotubes (MWCNTs) serve as a conductive backbone to disperse Sn 4 P 3 nanoparticles. When applied as the lithium container, the MWCNTs/Sn 4 P 3 @C composites demonstrate excellent cycling stability (delivering a high reversible capacity of 768.8 mA h g −1 after 100 cycles at 100 mA g −1 and 569.5 mA h g −1 after 1000 cycles at 1000 mA g −1 ) and rate capability (a de-lithiation capacity of 520.1 mA h g −1 maintained at a high current density of 2000 mA g −1 ). Furthermore, full cells composed of the MWCNTs/Sn 4 P 3 @C anode and the commercially available LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathode were also assembled. The result of cycling performance showed a reversible capacity of 507 mA h g −1 after 100 cycles, which is far superior to that of bare Sn 4 P 3 and MWCNTs/Sn 4 P 3 anodes with the reversible capacity lower than 100 mA h g −1 . These excellent electrochemical performances originate from a synergistic effect between the MWCNT conductive backbone and carbon shell protective layer. The MWCNT backbone can enhance the conductivity and serve as a framework to disperse Sn 4 P 3 nanoparticles, thus helping to accommodate the large volume changes during cycling, while the carbon shell not only can further enhance the conductivity but also minimize the side reaction between Sn 4 P 3 nanoparticles and electrolytes. MWCNTs/Sn4P3@C with a coaxial cable-like structure demonstrates remarkable cycling stability and rate capability.