Carbon‐Encapsulated Ni₃Se₄/CoSe₂ Heterostructured Nanospheres: Sodium/Potassium‐Ion Storage Anode with Prominent Electrochemical Properties

Abstract

Heterogeneous structures are used as energy storage devices because of their ability to accelerate charge transfer, which greatly contributes to the rate capability of devices. However, the construction of heterostructures with conspicuous electrochemical properties remains a huge challenge. In this study, a design of heterostructured Ni3Se4/CoSe2 nanospheres encapsulated by a carbon shell (Ni3Se4/CoSe2@C) synthesized through facile hydrothermal and annealing methods is presented. The Ni3Se4/CoSe2@C exhibits excellent cyclic performance with a capacity of 420 mA h g−1 at 0.5 A g−1 after 100 cycles for Na‐storage and 330.1 mA h g−1 at 0.1 A g−1 after 200 cycles for K‐storage. The excellent cyclic performance can be attributed to the carbon coating that maintains the structural stability and enhances electrical conductivity, and significantly, the heterostructures that promote ion/electron transport. The sodium storage mechanism of the Ni3Se4/CoSe2@C is revealed by ex situ X‐ray powder diffraction, ex situ high‐resolution transmission electron microscopy, and in situ electrochemical impedance spectra analyses. The first principles density functional theory calculation is performed to prove that the heterostructure on the Ni3Se4/CoSe2 interface can induce an electric field and thus improve the electrochemical reaction kinetics. This study provides an effective approach for constructing heterostructured composites for high‐performance alkaline batteries.

Hierarchical Co1.4Ni0.6P@C hollow nanoflowers assembled from ultrathin nanosheets as an anode material for high-performance lithium-ion batteries

“…First, the precursor of the NiCo-glycerate nanospheres was synthesized by the solvothermal method. 32 Subsequently, the precursor of NiCo-glycerate nanospheres was transformed into NiCo(OH) x hollow nanoflowers (NiCo(OH) x HNFs) through a hydrothermal method. Next, a uniform polydopamine (PDA) layer was coated on the surface of NiCo(OH) x HNFs under stirring in a tris solution for 10 h at room temperature.…”

Constructing SnO2–MoSe2heterojunction nanoflowers as high-rate and ultrastable anodes for sodium-ion half/full batteries

“…3f displays that the rate capability of SnO 2 /MoSe 2 is superior to most previously reported studies. 18,27–33 Fig. 3g compares the long-term cycle performance of SnO 2 /MoSe 2 , SnO 2 and MoSe 2 at 10 A g −1 ; the SnO 2 /MoSe 2 heterojunction electrode still maintains a promising discharge capacity of 364.3 mA h g −1 after 5000 cycles, while MoSe 2 and SnO 2 only stop after 1000 and 200 cycles, respectively.…”

“…3f displays that the rate capability of SnO 2 /MoSe 2 is superior to most previously reported studies. 18,[27][28][29][30][31][32][33] initial few cycles. It further conrms that the heterojunction can effectively enhance the stability of the structure.…”

Electrochemical performance of CoSe2 with mixed phases decorated with N-doped rGO in potassium-ion batteries

“…The peaks located at 59.6 eV is corresponding to Se-O bond formed by the inevitable surface oxidation of the transition metal selenides during the test. 22,23,42 The broad peak at around 61.2 eV is assigned to the Co 3p orbital. 41,44 Fig.…”

“…6,21 Aer the development in recent years, transition metal selenides with different nano-morphologies, such as CoSe 2 , Ni 3 Se 4 , MoSe 2 , etc., are oen used as anode materials for PIBs. 22,23 These transition metal selenides coated with different morphologies and types of carbon show good cycle stability and large residual capacitance in PIBs. For example, Xu et al prepared CoSe 2 -MoSe 2 /rGO composite electrode materials, and the formation of chemical bonds between the two signicantly improved the charge transfer in the electrochemical cycle.…”