Composites of NiSe2@C hollow nanospheres wrapped with Ti3C2Tx MXene for synergistic enhanced sodium storage

Sodium-ion batteries (SIBs) have the virtues of abundant sodium source and low price, but the serious volume expansion and poor cycle stability caused by the large sodium ion radius limit its practical application. Herein, we develop a three-dimensional (3D) Ti3C2Tx MXene wrapped NiSe2@C hollow nanospheres (NiSe2@C@MXene) composites for advanced sodium ion storage. The electrostatic self-assembly of MXene on NiSe2@C hollow nanospheres not only provides dual structural confinement on carbon coated NiSe2, but also efficiently inhibits the self-stacking of MXene. Taking advantage of the highly conductive 3D hierarchical network, the NiSe2@C@MXene electrode is endowed with enhanced electrochemical activity, fast electrochemical dynamic and abundant spatially confined active sites, leading to high reversibility and stable structural integration. Consequently, the NiSe2@C@MXene electrode provides a synergistic enhanced capacity of 327 mA h g(-1) at 2000 mA g(-1) after 4000 cycles, indicating high-rate capability and long-term stability. This work provides a new route toward developing MXene engineered Ni-based electrode materials for high-performance sodium storage.

Automated summary

A composite material consisting of three-dimensional Ti3C2Tx MXene wrapped NiSe2@C hollow nanospheres was developed for advanced sodium ion storage, exhibiting enhanced capacity, high-rate capability, and long-term stability. The electrostatic self-assembly of MXene on NiSe2@C hollow nanospheres provided dual structural confinement and efficient inhibition of self-stacking, leading to improved electrochemical activity and stable structural integration of the electrode.