Micro-mesoporous cobalt phosphosulfide (Co3S4/CoP/NC) nanowires for ultrahigh rate capacity and ultrastable sodium ion battery.

ABSTRACT

The construction of heterostructure materials has been demonstrated as the promising approach to design high-performance anode materials for sodium ion batteries (SIBs). Herein, micro-mesoporous cobalt phosphosulfide nanowires (Co3S4/CoP/NC) with Co3S4/CoP hetero-nanocrystals encapsulating into N-doped carbon frameworks were successfully synthesized via hydrothermal reaction and subsequent phosphosulfidation process. The obtained micro-mesoporous nanowires greatly improve the charge transport kinetics from the facilitation of the charge transport into the inner part of nanowire. When evaluated as SIBs anode material, the Co3S4/CoP/NC presents outstanding electrochemical performance and battery properties owing to the synergistic effect between Co3S4 and CoP nanocrystals and the conductive carbon frameworks. The electrode material delivers outstanding reversible rate capacity (722.33 mAh/g at 0.1 A/g) and excellent cycle stability with 522.22 mAh/g after 570 cycles at 5.0 A/g. Besides, the Ex-situ characterizations including XRD, XPS, and EIS further revealed and demonstrated the outstanding sodium ion storage mechanism of Co3S4/CoP/NC electrode. These findings pave a promising way for the development of novel metal phosphosulfide anodes with unexpected performance for SIBs and other alkali ion batteries.