A Robust Strategy for Engineering Fe₇S₈/C Hybrid Nanocages Reinforced by Defect-Rich MoS₂ Nanosheets for Superior Potassium-Ion Storage

Abstract

Metal sulfides have attracted tremendous research interest for developing high-performance electrodes for potassium-ion batteries (PIBs) for their high theoretical capacities. Nevertheless, the practical application of metal sulfides in PIBs is still unaddressed due to their intrinsic shortcomings of low conductivity and severe volume changes during the potassiation/depotassiation process. Herein, robust Fe7S8/C hybrid nanocages reinforced by defect-rich MoS2 nanosheets (Fe7S8/C@d-MoS2) were designed, which possess abundant multichannel and active sites for potassium-ion transportation and storage. Kinetic analysis and theoretical calculation verify that the introduction of defect-rich MoS2 nanosheets dramatically promotes the potassium-ion diffusion coefficient. The ex-situ measurements revealed the potassium-ion storage mechanism in the Fe7S8/C@d-MoS2 composite. Benefitting from the tailored structural design, the Fe7S8/C@d-MoS2 hybrid nanocages show high reversible capacity, exceptional rate property, and superior cyclability.

Synthesis and Applications of Nanostructured Hollow Transition Metal Chalcogenides

“…[126] For instance, Li et al used a self-template strategy to synthesize Fe 7 S 8 /C@d-MoS 2 hollow nanocages through a multi-step process. [127] The designed hollow structure is beneficial to the effective transmission of electrons and ions and improves electrochemical performance. The self-template strategy generally firstly synthesizes a well-defined MOFs structure, and then generates the target product through chemical reactions such as hydrothermal and sulfurization.…”

“…MIBs [192] Fe 7 S 8 /C@d-MoS 2 Hollow nanocages 505 mAh g −1 at 0.5 A g −1 , 318 mAh g −1 at 5 A g −1 286 mAh g −1 at 4 A g −1 , 500 cycles PIBs [127] SnS 2 @C Hollow nanobox 508 mAh g −1 at 0.1 A g −1 , 222 mAh g −1 at 2 A g −1 347 mAh g −1 at 1 A g −1 , 300 cycles 72% capacity retention PIBs [134] N-CoS 2 Yolk-shell nanospheres 744 mAh gZn −1 at 5 mA cm −2 165 h at 10 mA cm −2 ZABs [193] NiCo 2 S 4 Hollow spheres 1387.4 F g −1 at 1 A g −1 , 755 F g −1 at 10 A g −1 1387.5 F g −1 at 1 A g −1 , 4500 cycles 92.2% capacity retention SCs [194] For example, a semiconductor photocatalyst condenses electrons on the catalyst surface, thereby improving the photocatalytic CO 2 reduction ability. [69] Therefore, the preparation of some new-type, good-effect, and environment friendly photocatalysts has aroused great interest from many researchers.…”

“…In terms of electrochemical energy storage system, in addition to LIBs [190] and SIBs, [191] rechargeable batteries also include magnesium ion batteries (MIBs), [192] potassium ion batteries (PIBs), [127,134] and Zn-air batteries (ZABs), [193] etc. Among them, supercapacitors (SCs) and batteries are used as energy storage components and are part of the energy storage system.…”

Application of 2D Materials to Potassium‐Ion Hybrid Capacitors

“…Li et al constructed Fe 7 S 8 nanocages encapsulated by a defect-rich MoS 2 ultrathin nanosheet hybrid (Fe 7 S 8 /C@d-MoS 2 ) and employed it as anode materials for K + storage. [53] The specific Fe 7 S 8 /C@d-MoS 2 hollow structures benefit from an improved rate property and a longterm cycling stability owing to the multi-ion/electron channel. This can not only effectively relieve the pulverization of active materials caused by large volume changes but can also further enhance the wettability of the electrolyte for high-efficiency electrochemical kinetics.…”

SnS2 Nanosheets with RGO Modification as High-Performance Anode Materials for Na-Ion and K-Ion Batteries

“…With the intensification of environmental pollution, green renewable energy has currently become an active area of research [ 1 , 2 ]. Among numerous energy storage devices, sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) have gained extensive concern for energy storage because of their similar energy storage mechanisms to lithium-ion batteries (LIBs) and the abundant sodium and potassium resources [ 3 , 4 , 5 ]. However, the low capacity of commercial graphite anodes for Na-ion and K-ion storage has greatly limited the large-scale development of SIBs and PIBs [ 6 , 7 , 8 ].…”