Ultrathin V3S4 Embedded in Three-Dimensional Carbon Framework with V–C Bonding Towards Alkali-Ion Batteries

The construction of anode materials for alkali-ion batteries with high capacity and a long life span is significant and remains challenging. With the increasing interest in vanadium sulfide, V 3 S 4 possesses unique a structure and shows great promise for application in alkali-ion batteries, such as lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and potassium-ion batteries (PIBs). However, it still faces the problems of large volume changes and low electronic conductivities, which limits its practical application. Herein, ultrafine V 3 S 4 nanocrystals evenly integrated within three-dimensional (3D) porous N-doped carbon (N–C) by V–C bond are rational designed to address these issues. The interconnected N–C coating provides bi-continuous electron/ion transport pathways. Also, the 3D porous structure ensures a large surface area, as well as robust structural integrity, boosting reaction kinetics. Moreover, the strengthened interface coupling not only enhances the electron transfer at the interface, but also markedly strengthens structural stability. As expected, the as-prepared electrode showed superior lithium storage capacity, including a high specific capacity of 1021 mA h g −1 at 0.1 A g −1 , superior rate performance of 698 mA h g −1 at 2.0 A g −1 and excellent cycling stability and prolonged cycling stability of 635 mA h g −1 capacity retention over 2000 cycles at 2 A g −1 . Additionally, it also shows good electrochemical performance as an anode material for SIBs and PIBs. This work demonstrates the superiority of ultrafine crystal confined in a 3D porous carbon network to boost the electrochemical performance in various fields.