An Open‐Ended Ni₃S₂–Co₉S₈ Heterostructures Nanocage Anode with Enhanced Reaction Kinetics for Superior Potassium‐Ion Batteries

Abstract

Sulfides are perceived as promising anode materials for potassium‐ion batteries (PIBs) due to their high theoretical specific capacity and structural diversity. Nonetheless, the poor structural stability and sluggish kinetics of sulfides lead to unsatisfactory electrochemical performance. Herein, Ni3S2–Co9S8 heterostructures with an open‐ended nanocage structure wrapped by reduced graphene oxide (Ni‐Co‐S@rGO cages) are well designed as the anode for PIBs via a selective etching and one‐step sulfuration approach. The hollow Ni‐Co‐S@rGO nanocages, with large surface area, abundant heterointerfaces, and unique open‐ended nanocage structure, can reduce the K+ diffusion length and promote reaction kinetics. When used as the anode for PIBs, the Ni‐Co‐S@rGO exhibits high reversible capacity and low capacity degradation (0.0089% per cycle over 2000 cycles at 10 A g–1). A potassium‐ion full battery with a Ni‐Co‐S@rGO anode and Prussian blue cathode can display a superior reversible capacity of 400 mAh g–1 after 300 cycles at 2 A g–1. The unique structural advantages and electrochemical reaction mechanisms of the Ni‐Co‐S@rGO are revealed by finite‐element‐simulation in situ characterizations. The universal synthesis technology of bimetallic sulfide anodes for advanced PIBs may provide vital guidance to design high‐performance energy‐storage materials.

Zeolitic Imidazolate Frameworks Derived Co9S8/Nitrogen‐Doped Hollow Porous Carbon Spheres as Efficient Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries

“…The lattice intervals are determined to be 0.29 and 0.18 nm, which are attributed to the (311) and (440) planes of Co 9 S 8 crystal, respectively (Figure 1f). [18][19][20] The selected area electron diffraction (SAED) pattern of Co 9 S 8 NPs/NHCS-0.5 obviously demonstrates the diffraction spots of Co 9 S 8 crystal, which is in accordance with the HRTEM result (Figure 2f). In addition, the TEM-mapping images reveal that the C, N, and O elements are uniformly distributed on the carbon shells of Co 9 S 8 NPs/NHCS-0.5, meanwhile the Co and S are well overlapped, implying the pure phase formation of Co 9 S 8 crystal (Figure 2g-l, Figure S1g-l).…”

Constructing a novel heterostructure of NiSe2/CoSe2 nanoparticles with boosted sodium storage properties for sodium-ion batteries

“…The diffusion coefficients of Na + ions were studied with the GITT test according to eqn (1): 42 where D is the diffusion coefficient of Na + ions, and L (18 μm in Fig. S18†) and τ are the Na + ion diffusion distance and constant current titration time, respectively.…”

“…41 As a result, the Na storage properties of heterostructures can be significantly boosted by the accelerated conversion reaction kinetics/electrochemical kinetics and rich disorder resulting from the heterointerface. 42,43…”

New enhancement mechanism of an ether-based electrolyte in cobalt sulfide-containing potassium-ion batteries

“…Two phases of CoS (PDF#75-0605) and Co 8 S 9 (PDF#86-2273) can be detected, indicating that the CoS@RGO hybrid is composed of a mixed-phase structure. 35 To inspect the surface information, X-ray photoelectron spectroscopy (XPS) of the CoS@RGO hybrid is conducted and the results are shown in Fig. S3 †.…”