Sn/P@G-CNTs composites as high-performance anode materials for sodium-ion batteries

Abstract

Tin/phosphide (Sn/P) based alloys have been regarded as one of the promising anodes for advanced sodium-ion batteries due to their advantages of low-cost and proper redox potentials to Na/Na+. However, because of the serious volume expansion in the Na storage process, Sn/P-based materials generally suffer from rapid capacity decay during the cycle. Herein, a novel tin/phosphorus@graphite-carbon nanotubes (Sn/P@G-CNTs) composite was synthesized via a rational high-energy ball milling (HEBM) method. SEM and TEM results reveal that the separated Sn/P species are homogeneously dispersed in the G-CNTs matrix, which can accommodate large volume expansion and generate good electrical contact during cycle. As a result, the fabricated Sn/P@G-CNTs electrode exhibits a high reversible capacity (1048 mA h g−1 after 100 cycles at 100 mA g−1) with an initial Coulombic efficiency of 79.84% and good rate capability, better than those of Sn/P@G and Sn/P@CNTs counterparts. The design strategy and synthesis method of Sn/P@G-CNTs can provide an insight on constructing cost-effective sodium-ion batteries.