Construction of Bi2Se3/NiSe2 heterostructure inspired by the sodium storage voltage complementarity for efficient sodium storage

Heterostructure engineering, especially for those constructed by bimetallics with different sodium storage mechanisms, can efficiently improve the electrochemical activity and conductivity of the anode materials. Herein, the Bi 2 Se 3 /NiSe 2 heterostructure with dual mechanisms is designed via simple hydrothermal and selenization processes. The constructed hierarchical structure is composed of the two-dimensional nanoplates formed by Bi 2 Se 3 species, coupled with carbon-coated NiSe 2 nanoparticles. The abundant Bi 2 Se 3 /NiSe 2 heterointerfaces and effective active sites can accelerate the infiltration of the electrolyte and significantly improve the electrochemical activity. Notably, the designed Bi 2 Se 3 /NiSe 2 @C possesses a unique complementarity originating from the different sodium storage mechanisms and reaction voltages of the two components. This can realize sodium storage in the whole operating voltage range, resulting in a high sodium storage capacity. Furthermore, a built-in electric field effect induced by the Bi 2 Se 3 /NiSe 2 heterojunction can accelerate electronic transfer and sodium ion diffusion while enhancing the Na + adsorption energy. Reassuringly, a high initial capacity of 632.6 mAh g −1 at 0.5 A g −1 , exceptional cycling stability (322.9 mAh g −1 at 3 A g −1 over 1270 cycles), and rate capability can be achieved for Bi 2 Se 3 /NiSe 2 @C. This work supplies a new idea for the design and preparation of novel heterostructures with complementary reaction potentials.