Heterostructure Interface Construction of Cobalt/Nickel Diselenides Hybridized with sp²–sp³ Bonded Carbon to Boost Internal/External Sodium and Potassium Storage Dynamics

Abstract

Metal selenides exhibit great potential in energy storage systems owing to their diversified species, large interlayer spaces, and high theoretical specific capacity according to multiple ion-storage behaviors. In this work, heterostructured CoSe 2 / NiSe 2 coupled with sp 3 bonded N-doped carbon coating layers and interconnected with sp 2 bonded carbon nanotubes is synthesized through a room-temperature wet-chemistry approach and a selenization route with Co−Ni Prussian blue analogues as the precursor. The hybrid exhibits enhanced energy storage properties when utilized as an anode material for sodium-and potassium-ion batteries. The excellent performance of the hybrid can be indexed to the delicately design of the CoSe 2 /NiSe 2 heterostructure and the hybridization of it with sp 2 and sp 3 bonded carbonaceous materials synchronously. Experimental and theoretical calculation results demonstrate the heterostructure is constructed to acquire charge transfer driving forces to boost internal reaction dynamics. And there is a combination of the dual advantages of sp 3 and sp 2 bonded carbon, possessing not only the exceptional mechanics buffer capability of N-doped carbon coating layers but also the excellent electrical characteristics of carbon nanotubes to promote external reaction dynamics. In addition, to elucidate the differential sodium/potassium storage capability of the hybrid, theoretical calculations are further performed to indagate the adsorption energy of sodium and potassium on the CoSe 2 /NiSe 2 heterointerface by establishing five Na/K adsorption sites. The research provides an effective strategy for the melioration of internal/external reaction dynamics to deliver ions durably and efficiently in energy storage regions.