Iron sulfides are widely explored as anodes of sodium-ion batteries (SIBs) owing to high theoretical capacities and low cost, but their practical application is still impeded by poor rate capability and fast capacity decay. Herein, for the first time, we construct highly dispersed Fe7S8 nanoparticles anchored on a porous N-doped carbon nanosheet (CN) skeleton (denoted as Fe7S8/NC) with high conductivity and numerous active sites via facile ion adsorption and thermal evaporation combined procedures coupled with a gas sulfurization treatment. Nanoscale design coupled with a conductive carbon skeleton can simultaneously mitigate the above obstacles to obtain enhanced structural stability and faster electrode reaction kinetics. With the aid of density functional theory (DFT) calculations, the synergistic interaction between CNs and Fe7S8 can not only ensure enhanced Na+ adsorption ability but also promote the charge transfer kinetics of the Fe7S8/NC electrode. Accordingly, the designed Fe7S8/NC electrode exhibits remarkable electrochemical performance with superior high-rate capability (451.4 mAh g–1 at 6 A g–1) and excellent long-term cycling stability (508.5 mAh g–1 over 1000 cycles at 4 A g–1) due to effectively alleviated volumetric variation, accelerated charge transfer kinetics, and strengthened structural integrity. Our work provides a feasible and effective design strategy toward the low-cost and scalable production of high-performance metal sulfide anode materials for SIBs.

As one type of promising anode for sodium-ion batteries (SIBs), nickel diselenide (NiSe2) has stimulated considerable attention. However, its wide practical application has been greatly limited by the sluggish kinetics, low electrical conductivity, as well as severe volume changes and aggregation of particles during repeated cycling. In this work, we demonstrate a facile strategy to achieve self-supporting carbon nanosheet arrays densely decorated with NiSe2 nanoparticles on carbon cloth through the one-pot hydrothermal formation of intermediate glucose-intercalated Ni­(OH)2 as both the nickel precursor and carbon source, followed by carbonization and selenization processes. The strongly coupled NiSe2 nanoparticles with a carbon nanosheet matrix can endow the improved sodium storage performance owing to the robust structural integrity, abundant active sites, as well as accelerated charge transfer kinetics. As expected, the optimal anode of NiSe2/C hybrid arrays exhibits a remarkable reversible capacity of 465 mAh g–1 at a current density of 0.5 A g–1 after 350 cycles and an outstanding rate capability of 259 mAh g–1 at 5 A g–1. We propose that the present study shall unravel more insights into the delicate design and exploration of NiSe2-based anode materials for SIBs with high performance.

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As a result of the high theoretical capacities, transition metal sulfides have attracted increasing attention as potential anodes for sodium-ion batteries (SIBs), but severely suffer from large volumetric variations, sluggish kinetics, and polysulfide shuttling. Herein, utilizing metal–organic frameworks (MOFs) as functional templates, heterostructured CoS2/FeS nanoparticles confined in a hollow N-doped carbon framework are successfully fabricated via a controlled ion-exchange reaction combined with subsequent carbonization and sulfurization processes. The construction of CoS2/FeS heterointerfaces promotes electron transfer and provides more active sites, while the derived N-doped carbon framework with a unique hollow interior effectively improves the electrical conductivity, alleviates the volumetric variations, and facilitates the sodium storage process with shortened Na+ diffusion paths. As anodes for SIBs, the optimal CoS2/FeS hybrid composite exhibits a high initial Coulombic efficiency (ICE) of 89.3%, a prolonged cycle life with a capacity of 494 mAh g–1 over 500 cycles under a current density of 1.0 A g–1, and an excellent rate capability of 428 mAh g–1 at 5.0 A g–1, showing the great promise for SIBs. This research offers an efficient and feasible approach for exploring and fabricating bimetallic sulfide heterostructures with a unique hollow structure for high-performance metal-ion batteries.