Construction of MoO₂ Ultra-uniformly Coated FeS₂ with Tailored Interfacial Traits toward Improved Energy Storage

Abstract

Iron disulfide (FeS 2 ), a low-cost material, displays considerable theoretical specific capacity (894 mA h g −1 ) but still suffers from shuttling of polysulfides and sluggish kinetics. The MoO 2 electrocatalyst has been successfully applied in Li−S systems, bringing about fascinated electrochemical improvements. Herein, through the gasification coating manners, the ultra-uniform distribution of MoO 2 with abundant catalytic sites is surprisingly obtained, incorporating with the establishment of interfacial Fe− O−Mo bonds. Benefiting from the unique structural traits, optimized FeS 2 @MoO 2 delivers an initial discharge capacity of 1271 mA h g −1 . In addition, after 100 cycles, the capacity of FeS 2 @ MoO 2 could reach ∼308 mA h g −1 , larger than that of pristine FeS 2 . Supported by the kinetic analysis, it could be found that the existing Fe−O−Mo bonds contribute to enhanced ion/e − diffusion behaviors during the intercalation/deintercalation process, ultimately resulting in outstanding lithium-ion storage capacity. Moreover, benefitting from the detailed resistance analysis and the galvanostatic intermittent titration technique test, the existence of MoO 2 and Fe−O−Mo interfacial bonds could facilitate the diffusion of ions/electrons transferring and structural stability. Thus, this work is expected to provide insights into the construction of MoO 2 ultra-uniformly coated FeS 2 with tailored interfacial traits in energy storage systems.

Promoting overall sulfur redox kinetics for Li–S batteries via interfacial synergy in a NiS–NiTe2 heterostructure-modified separator

“…38,39 Overall, heterogeneous structures exhibit strong adsorption capabilities for polysulfides and demonstrate high catalytic activity in the conversion of polysulfides, making Li–S batteries constructed with heterogeneous structure materials typically exhibit outstanding electrochemical performance. Reported combinations of heterogeneous structure materials currently include oxide–oxide, 40,41 oxide–sulfide, 42–44 oxide–nitride, 45,46 sulfide–sulfide, 47,48 sulfide–nitride, 49,50 and other composite material systems.…”