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Aqueous Zn-ion batteries (AZIBs) have acquired great attention owing to their nontoxicity, high safety, and sustainable Zn resources. Nevertheless, the deficiency of applicable electrode materials hampers the advancement of the electrochemical performance for AZIBs. Herein, a N-graphene coupling vanadium tetrasulfide aerogel (VS4@NGA) forming a sponge-like heterostructured architecture is constructed through a hydrothermal and a following freeze-dehydration approach. The unique composite is evaluated as a binder-free electrode for AZIBs and presents competitive zinc storage performance (two times improvement in specific capacity over pristine VS4). The calculations based on density functional theory and electrochemical experimental studies demonstrate that the interconnected porous architecture, meliorated electrical conductivity, decreased adsorption energy, and Zn2+ diffusion energy barrier driven by the combination of VS4 with NGA synergistically realize the enhanced energy storage dynamics and exceptional electrochemical properties of the composite. The reversible Zn ion insertion/extraction reaction mechanism of the composite is clarified by a sequence of ex-situ elemental and structural characterizations. Moreover, the soft-packaged batteries assembled using the composite aerogel suggest the practical application ability of the material in electronic devices. This research offers a simple avenue for constructing a binder-free aerogel-based cathode, which provides a progressive paradigm for the advancement of AZIBs.

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.

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