Yolk-shell Nanospheres Research Articles

Defective ZnS yolk-shell nanospheres with sulfur vacancy for efficient sonocatalytic H2 production

In this study, the defective ZnS yolk shell nanospheres are synthesized through a facile solvothermal method followed by a calcination process to introduce sulfur vacancies. The defective ZnS yolk-shell nanospheres show excellent sonocatalytic performance for hydrogen production, as compared to ZnS nanospheres and other commonly used sonocatalysts. The enhanced sonocatalytic activity is attributed to the synergistic effect of the yolk-shell structure and the introduction of sulfur vacancies. Furthermore, the defective ZnS yolk-shell nanospheres demonstrate good stability for sonocatalytic hydrogen production.

Yolk-shell nanospheres based silane-functionalized carbon dots: Designed synthesis and application in highly selective determination of aflatoxin biosynthesis-related genes nor-1 in cereal crops

This study presented advanced monitoring approaches for the aflatoxin gene cluster in Aspergillus flavus and Aspergillus parasiticus, which are effective tools for controlling aflatoxin proliferation in the food chain. A novel approach involved a ratiometric fluorescence probe based on yolk-shell nanospheres (bCDs@SiO2@gQDs). The probe's fluorescence was activated by DNA hybridization with the modified bCDs@SiO2@gQDs and gold nanoparticles (AuNPs), functioning through donor–acceptor pairs. The exceptional properties of the gQDs and the high FRET efficiency of this system established a functionalized platform for DNA labeling. When the nor-1 gene was present, FRET between the gQDs and AuNPs triggered fluorescence quenching, enabling nor-1 gene detection. The yolk-shell nanostructure of the fluorescent nanoprobes provided an internal reference, reducing experimental errors due to background noise, instrumentation factors, and probe concentration. This allowed for accurate and highly sensitive quantitative determination of the nor-1 gene. The ratiometric fluorescence assay demonstrated a broad linear range (0.1–100 nM) and a low detection limit (12.83 pM) for the nor-1 gene. Tests on non-contaminated maize samples spiked with various concentrations of the nor-1 gene achieved recovery rates between 95.43 % and 101.46 %. This biosensor represents a significant advancement in food safety, offering a simple, rapid, and sensitive method for monitoring agricultural products.

Active metals decorated NiCo2O4 yolk-shell nanospheres as nanoreactors for catalytic reduction of nitroarenes and azo dyes

Transition-metal oxides (TMOs) have received a great deal of research attention and have been widely used in a variety of fields. However, conventional TMOs do not possess high specific surface area, sufficient active site on their surfaces, and limited their applications in catalysis. This study presents a two-step method for synthesizing active metal (M) decorated NiCo2O4 (M/NiCo2O4, M = Pd or Cu) nanospheres with yolk-shell nanostructures. Taking advantage of the unique morphology and the combination of dual active components (i.e., active NiCo2O4 substrate and decorated active metal), the as-prepared M/NiCo2O4 yolk-shell nanospheres can be employed as nanoreactors in the organic reactions. In catalyzing the reduction of a representative nitroarene (i.e., 4-NP) by NaBH4, the Pd/NiCo2O4 nanoreactors exhibit a superior catalytic efficiency to their counterparts (Cu/NiCo2O4 and NiCo2O4). The turnover frequency is much higher than that of various TMOs supported nanocatalysts have been reported over the past five years. Furthermore, the Pd/NiCo2O4 nanoreactors show excellent stability and common applicability of the reduction of various substituted nitrobenzenes and azo dyes. This work provides new rational design concept and preparation strategy for efficient nanoreactors with dual active components and sheds light on the practical application of chemical reactions.

Tailoring oxygen vacancies in Co3O4 yolk-shell nanospheres via for boosted peroxymonosulfate activation: Single-electron transfer and high-valent Co-oxo species-dominated non-radical pathways

As Co3O4 represents a promising material for peroxymonosulfate (PMS) activation, a yolk-shell-structured nanosphere, Co3O4-x-0.20, is developed here for maximizing its catalytic activity by governing electronic structures via tailoring oxygen vacancies (OV) of Co3O4. This OV-tailored Co3O4 enables single-electron transfer and generates high-valent cobalt-oxo species (Co(IV) = O) to achieve the fastest phenol degradation. The single-electron transfer is unraveled by an electron donation of Co atoms near OV to O2 to form O2− followed by O2 evolution after 1O2 and the charge balance maintained by an electron acquisition from phenol by the electron-deficient Co atoms. Meanwhile, the generation of Co(IV) = O by the cleavage of the SO bond in the Co(II)-O-SO3-OH complex accepts electrons from phenol to turn back to Co(II) and Co(III), causing phenol oxidation. These results demonstrate the pre-eminence of Co3O4-x-0.20 over the reported catalysts for phenol degradation and also offer insights into the mechanism of OV triggering electron donation and enhancing Co(IV) = O generation.

Facilely Direct Construction, White-Light Emission, and Color-Adjustable Luminescence of LaF3 :Pr3+ @SiO2 Yolk-Shell Nanospheres with Moisture Resistance.

Poor water stability and single luminous color are the major drawbacks of the most phosphors reported. Therefore, it is important to realize multicolor luminescence in a phosphor with single host and single activator as well as moisture resistance. LaF3 :Pr3+ @SiO2 yolk-shell nanospheres are facilely obtained by a designing new technology of a simple and cost-effective electrospray ionization combined with a dicrucible fluorating technique without using protective gas. In addition, tunable photoluminescence, especially white-light emission, is successfully obtained in LaF3 :Pr3+ @SiO2 yolk-shell nanospheres by adjusting Pr3+ ion concentrations, and the luminescence mechanism of Pr3+ ion is advanced. Compared with the counterpart LaF3 :Pr3+ nanospheres, the water stability of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres is improved by 15% after immersion in water for 72h, and the fluorescence intensity can be maintained at 86% of the initial intensity. Furthermore, by treating the yolk-shell nanospheres with hydrofluoric acid, it is not only demonstrated that the shell-layer is SiO2 but also core-LaF3 :Pr3+ nanospheres are obtained. Particularly, only fluorination procedure among the halogenation can produce such special yolk-shell nanospheres, the formation mechanism of yolk-shell nanospheres is proposed detailedly based on the sound experiments and a corresponding new technology is built. These findings broaden practical applications of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres.

N-Doped Yolk–Shell Carbon Nanospheres with “Carbon Bridges” for Supercapacitors

N-doping multilocular carbon spheres are beneficial to improving the electrical property due to their unique pore structure and elemental composition; nevertheless, there is a great challenge to fabricate this structure in a facile way. In this work, an N-doping yolk–shell carbon nanosphere with a “carbon bridges” structure was prepared by domain-limited carbonization of RF@SiO2 (RF = resorcinol-formaldehyde resin) with ethylenediamine (EDA) as the nitrogen precursor. The structure of the “carbon bridges” and the carbon shell’s thickness can be adjusted by controlling the thickness of the silica layer, resulting in a change in morphology (from dense nanospheres to yolk–shell nanospheres). The optimized yolk–shell carbon nanospheres (C@C-2 nanospheres) exhibited high N-doping, an abundant micro-mesoporous structure, and an optimum “carbon bridges” structure, contributing to a high-rate capability in a supercapacitor, which was reflected in the energy storage dynamics. Herein, C@C-2 nanospheres, as an electrode material for supercapacitors, presented a reversible specific capacitance of 373.3 F g–1 at 0.5 A g–1 in 2 M KOH and retained a well-advanced capacitance retention capability (95.8%) at 4 A g–1 for more than 10,000 cycles. This work sheds light on an avenue to design high-performance porous carbons for efficient energy storage.

Convenient hydrothermal treatment combining with “Ship in Bottle” to construct Yolk-Shell N-Carbon@Ag-void@mSiO2 for high effective Nano-Catalysts

More active sites will be exposed when noble metal particles are loaded on the core of yolk-shell nanospheres (NM-YSNS) to give higher metal utilization rate, catalytic activity, and good recycle stability. Herein, we adopt an efficient strategy to access the high-performance NM-YSNS via “ship in bottle” mindset on loading Ag nanoparticle on the core surface of core–shell structure accurately and the core shrinkage on forming yolk-shell structure. First, we systematically investigated the mechanism of SiO2 coating 3-aminophenol-co-formaldehyde nanoparticles to generate 3-aminophenol-co-formaldehyde@mesoporous SiO2 core–shell nanospheres (3-APF@mSiO2 CSNS). Interestingly, the core surface of 3-APF@mSiO2 CSNS became uneven after hydrothermal process, which provided positions for Ag, then additional Ag+ could reach the 3-APF surface through the mSiO2 shell and be in situ reduced into Ag particles by –NH- and –NH2 there. Similarly, the 3-APF@Au@mSiO2 CSNS were prepared successfully. After carbonizing 3-APF@Ag@mSiO2 CSNS, the N-Carbon@Ag-void@mSiO2 YSNS was obtained. The NM-YSNS catalyst had a high specific surface area of 258.8 m2g−1, mSiO2 shell of 3.8 nm mesoporous size, and core loaded with Ag particles firmly, showing a high turnover frequency of 137.08 h−1 and good recycle stability in catalytic reduction of 4-nitrophenol for preparing 4-aminophenol.

Superior Electrocatalyst for All‐pH Hydrogen Evolution Reaction: Heterogeneous Rh/N and S Co‐Doped Carbon Yolk–Shell Nanospheres

AbstractDesign of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions has attracted significant attention. In particular, it is still a considerable challenge since the HER kinetics of Pt in alkaline solutions is about two to three orders of magnitude lower than that in acidic conditions. Herein, a heterogeneous yolk–shell nanostructure with Rh nanoparticles embedded in S, N co‐doped carbon nanospheres prepared by a facile self‐template method is reported. The optimized electrocatalyst can achieve an extremely small overpotential of 13.5 mV at 10 mA cm‐2, low Tafel slope of 25.5 mV dec‐1, high turnover frequency of 0.143 s‐1 (at −75 mV vs. reversible hydrogen electrode), and long‐term durability for 10 h, which is the record‐high alkaline HER activity among the ever‐reported noble metal based catalysts. These striking performances are ascribed to the optimized electronic structure and unique heterogeneous yolk–shell nanostructure. More importantly, it is also demonstrated that the obtained electrocatalyst exhibits superior activities in all pH range, which is better than commercial Pt/C and Rh/C catalysts. This work proves that Rh‐based nanomaterials are promising superior electrocatalysts in a wide pH range and nanostructure design is a powerful tool to increase the mass/electron transfer during reaction.

Controlled Synthesis of Nitrogen-Doped Yolk–Shell Carbon Nanospheres: Tailoring Yolk Size for Lithium–Sulfur Batteries

Nitrogen-doped yolk–shell carbon nanoparticles are one of the most promising functional nanomaterials for various potential applications because of their functionality and adaptability in both the hollow shells and yolks. Yolk–shell nanospheres are known for widely adopted template-based routes, which prove to be expensive and cumbersome and showed inadequate capability to build complex internal structures. Herein, a facile and controllable strategy for fabricating nitrogen-doped yolk–shell carbon nanospheres was proposed through a simple leaching process. The production of the yolk–shell structure is based on the selective dissolution of inhomogeneous solid polymer nanospheres using methanol as leaching agent. The yolk sizes of the nanospheres can be controlled in the range 110–360 nm by simply varying the number of leaching times. In particular, results of the electrochemical properties of the prepared nanospheres with different yolk size suggest that the optimal yolk–shell nanospheres with a yolk size of ∼230 nm delivered the best cycling performance and good capacity retention of 582 mAh g–1 at 1 C after 200 cycles. We believe that the proposed strategy will play a crucial role in energy storage application.

High catalytic performance non-enzymatic H2O2 sensor based on Cu2O@Cu9S5 yolk-shell nanospheres

It is urgent to develop highly active catalysts toward hydrogen peroxide (H2O2) sensor in many industrial and biological processes, which usually is limited by high cost of instrumentation requirements and low-accuracy detection at low level. Herein, Cu2O@Cu9S5 yolk-shell nanospheres has been synthesized via a facial wet chemical method and applied as electrocatalyst for non-enzymatic H2O2 sensor. These Cu2O@Cu9S5 yolk-shell nanospheres with mean sizes of 230 nm consisting of Cu2O conductive core and Cu9S5 shell show numerous advantageous characteristics of well-sustained structural integrity, the homogeneous particle size distribution and visible mesoporosity morphology. The significantly improved electrocatalytic activity by catalyzing H2O2 of the Cu2O@Cu9S5 yolk-shell nanospheres as a sensor has been obtained by comparing with those neat Cu2O nanospheres and Cu9S5 hollow nanospheres. This noticeable property is largely due to the synergistic catalysis effect of the contribution of the Cu2O and Cu9S5. Cu2O@Cu9S5 yolk-shell nanospheres based non-enzymatic H2O2 sensor displays the relatively wide linear range from 0.1 μM to 3.5 mM with a high sensitivity of 299.74 μA mM−1 cm−2 but low detection limit of 28.83 nM (S/N ≥ 3) for electrochemical detection of H2O2, which is potentially superior to other similar Cu2O-based sensors that has been reported in the literatures. Additionally, this sensor also demonstrates excellent selectivity of H2O2 in the presence of various coactive interferences. This novel Cu2O@Cu9S5 yolk-shell nanospheres electrocatalyst provides a broad application prospect for H2O2 sensing.

Ag@ZnO yolk-shell nanospheres for high-performance ethanol sensor

Ag@ZnO yolk-shell nanospheres (Ag@ZnO YSNSs) are fabricated via a simple sonochemical method for chemical sensor application. It is found that the Ag@ZnO YSNSs exhibits remarkable sensitivity and ultra-high response towards ethanol vapor. Compared with the pristine ZnO hollow nanosphere (ZnO HNSs), Ag@ZnO YSNSs based gas sensor reduced the optimum working temperature from 420 to 320 °C, shorten the response/recovery time from 55/18 to 23/15 s, optimized the detection limit from 5.20 to 0.88 ppm, and enhanced the sensor response from 66 to 250. The unique yolk-void-shell nanostructure, the catalytic effect of noble metal Ag and abundant oxygen vacancies in Ag@ZnO YSNSs are responsible for that improvement.

Bimetallic sulfide NiCo2S4 yolk-shell nanospheres as high-performance cathode materials for rechargeable magnesium batteries.

Constructing bimetallic sulfides with ideal structures could effectively alleviate the poor cycling stability of rechargeable Mg batteries due to a bimetallic synergistic effect. An exquisite yolk-shell structured bimetallic sulfide NiCo2S4 synthesized via a two-step solvothermal hydrothermal method is investigated as a cathode material for rechargeable Mg batteries. With the bimetallic strategy and well-designed architecture, the as-synthesized yolk-shell NiCo2S4 exhibits outstanding Mg-storage performance, demonstrating a superior reversible capacity (270 mA h g-1 at 50 mA h g-1), a high rate capability, and a specific capacity retention of 91% over 400 cycles (2.2% capacity decay per cycle). The in-depth mechanism investigation reveals the two-step conversion reaction process and the bimetallic synergistic effect in the Mg-storage process. Based on DFT calculations and kinetic investigations, the bimetallic synergistic effect effectively alleviates the Jahn-Teller effect and distortion in the crystal lattices and increases active reaction sites, thus largely enhancing the electrochemical Mg-storage performance. The superior electrochemical performance of NiCo2S4 not only demonstrates the viability of the bimetallic strategy but also sheds light on the use of nanostructure design for high-performance cathode research.

Novel synthetic strategy for a nanostructured metal hydroxysulfide‐C and its initial electrochemical investigation as a new anode material for potassium‐ion batteries

Efforts have been made to develop highly promising electrode materials for K-ion batteries (KIBs) by exploring new compositions, stable nanostructures, and combinations of various carbonaceous materials to overcome the slow reaction dynamics of K-ion. Recently, multiple anionic anode materials, such as metal hydroxychlorides, metal hydroxycarbonates, and metal hydroxysulfides, which contain metal−OH bonds, have caught attention as anode materials for Li- and Na-ions batteries owing to their ability to enhance the overall electrochemical kinetics by forming intrinsic electric fields at nanoscale heterointerfaces. Herein, a new synthetic strategy for metal [email protected] yolk-shell nanosphere was introduced, and the electrochemical reaction mechanism between the metal hydroxysulfide and K-ion was initially investigated by rational structural and electrochemical analyses. This work synthesized yolk-shell nanospheres having a configuration of metal [email protected]@metal hydroxide-C by water-vapor-assisted heat treatment without requiring a strong alkali solution. Cobalt [email protected] nanospheres were finally transformed into cobalt [email protected] yolk-shell nanospheres through a room-temperature sulfidation process. The metal hydroxysulfide transformed into a heterostructured nanocomposite consisted of metal hydroxide and metal sulfide following the initial cycle. The rationally nanostructured cobalt [email protected] electrode exhibited high-rate capability (138.0 mA h g−1 at 5.0 A g−1) and long-term cycling stability (158.4 mA g−1 at 1.0 A g−1 following 300 cycles) in KIBs.

One-pot synthesis of MoS2/CoS2 yolk-shell nanospheres

In this work, MoS2/CoS2 yolk-shell nanospheres are synthesized by a one-pot hydrothermal reaction. Furthermore, the yolk-shell spherical morphologies are characterized and confirmed by SEM, TEM characterizations; and the components of CoS2 and MoS2 are investigated by XRD and XPS analysis. It is revealed that the Co precursor and thiourea result in the formation of hollow CoS2 nanospheres, while the Co precursor, Mo precursor and thiourea lead to the fabrication of MoS2/CoS2 yolk-shell nanostructure. The possible growth mechanism of MoS2/CoS2 yolk-shell nanospheres is suggested based on the comparative experiments and characterization of intermediate samples. This research provides a feasible and new strategy to prepare the MoS2/CoS2 hybrid material with yolk-shell architecture.

P-Doped Ni/NiO Heterostructured Yolk-Shell Nanospheres Encapsulated in Graphite for Enhanced Lithium Storage.

The development of high-efficiency lithium-ion battery electrodes composed of recycled materials is crucial for the commercialization of retired batteries, but it remains a significant barrier. The usage and recycling of spent graphite are encouraged by the huge number of batteries that are going to be dismantled. Here, an anode made of phosphorus-doped Ni/NiO yolk-shell nanospheres embedded on wasted graphite is developed. Electroless deposition and a subsequent heat-treatment procedure are used to make it in a methodical manner. The internal vacuum space of the nanospheres mitigates volume expansion and facilitates Li+ diffusion, whereas the embedded metallic Ni and conductive graphite layer expedite charge transfer. The optimal reusable composite electrode is ecologically benign and has high specific capacities (724 mAh g-1 at 0.1 A g-1 ) as well as outstanding cycle stability (500 cycles). The unusual 3D sandwich-like arrangement with strong spent graphite, the yolk-shell hetero-structure, continuous electron/ion transport routes, and attractive structure stability all contribute to this degree of performance. Such a nanoscale design and engineering strategy not only provides a green recovery method for anode graphite, but also enlightens other nanocomposites to boost their lithium storage performance.

Dual carbon and void space confined SiOx/C@void@Si/C yolk-shell nanospheres with high-rate performances and outstanding cyclability for lithium-ion batteries anodes

Silicon-based anode materials with high theoretical capacity have great challenges of enormous volume expansion and poor electronic conductivity. Herein, a novel dual carbon confined SiOx/C@void@Si/C yolk-shell monodisperse nanosphere with void space have been fabricated through hydrothermal reaction, carbonization, and in-situ low-temperature aluminothermic reduction. Furthermore, the O/Si ratio and void space between SiOx/C core and Si/C shell can be effectively tuned by the length of aluminothermic reduction time. The SiOx/C core plays a role of maintaining the spherical structure and the void space can accommodate the volume expansion of Si. Moreover, the inner and outer carbons not only alleviate volume variation of SiOx and Si but also enhance the electrical conductivity of composites. Benefiting from the synergy of the double carbon and void space, the optimized VSC-14 anode affords prominent cycle stability with reversible capacity of 1094 mAh g−1 after 550 cycles at 200 mA g−1. By pre-lithiation treatment, the VSC-14 achieves an initial Coulombic efficiency of 93.27% at 200 mA g−1 and a reversible capacity of 348 mAh g−1 at 5 A g−1 after 4000 cycles. Furthermore, the pouch cell using VSC-14 anode and LiFePO4 cathode delivers a reversible capacity of 138 mAh g−1 at 0.2C. We hope this strategy can provide a scientific method to synthesis yolk-shell Si-based materials.

Constructing a Stable Si-N-Enriched Interface Boosts Lithium Storage Kinetics in a Silicon-Based Anode.

The stable operation of a SiOx anode largely depends on the intrinsic chemistry of the electrode/electrolyte interface; however, an unstable interface structure and undesirable parasitic reactions with the electrolyte of the SiOx anode often result in the formation of a fragile solid-electrolyte interphase (SEI) and serious capacity decay during the lithiation/delithiation process. Herein, a Si-N-enriched N-doped carbon coating is constructed on the surface of SiOx yolk-shell nanospheres (abbreviated as SiOx@NC) to optimize the SEI film. The two-dimensional covalently bound Si-N interface, on one hand, can suppress the interfacial reactivity of the SiOx anode to enable the formation of a thin SEI film with accelerated diffusion kinetics of ions and, on the other hand, acts as a Li+ conductor during the delithiation process, allowing Li+ to diffuse rapidly in the SiOx matrix, thereby improving the long-term cycling stability and rapid charge/discharge capability of the SiOx anode. A series of characterizations show that the interface charge-transfer barrier and the Li+ diffusion energy barrier through the SEI film are the main factors that determine the interfacial electrochemical behavior and lithium storage performance. This work clarifies the relationship between the SEI characteristics and the interfacial transfer dynamics and aims to offer a more basic basis for the screening of other electrode materials.

Synthesis of MnSe @C yolk‐shell nanospheres via a water vapor‐assisted strategy for use as anode in sodium‐ion batteries

This study introduces a simple and eco-friendly synthetic strategy for yolk-shell nanospheres that consist of manganese selenide yolks and carbon shells (MnSe@C) by reacting manganese salt impregnated in the porous hollow carbon nanospheres (HCNS) with H2O vapor. First, manganese salt dissolved in ethanol was impregnated into the spacious pores of the HCNS by capillary force. Then, heat treatment of the powder in the presence of H2O triggered the nucleation and crystal growth of manganese hydroxide, resulting in the formation of HCNS whose central voids are filled with multiple nanoparticles. Subsequent selenization yielded yolk-shell nanospheres with MnSe@void@carbon configuration. MnSe@C was applied as the anode for sodium-ion batteries (SIBs), and the following electrochemical reaction was confirmed from various analytical techniques: MnSe +2Na+ + 2e− ↔ Mn + Na2Se. MnSe@C nanospheres exhibited stable cycle performance up to 1000 cycles at 0.5 A g−1, wherein a reversible capacity of 222 mA h g−1 was delivered in the 1000th cycle. Furthermore, MnSe@C nanospheres exhibited a fair rate performance (209 mA h g−1 at 2.0 A g−1).

The dependence of Cu2O morphology on different surfactants and its application for non-enzymatic glucose detection

Herein, the Cu2O yolk-shell nanospheres, nanocubes and microcubes were successfully prepared by a simple seed-medium process. The formation of the Cu2O yolk-shell nanospheres can be attributed to the self-assembly process caused by the introduction of the seed medium. The formation mechanism of our obtained Cu2O yolk-shell nanospheres and the dependence of Cu2O morphology on different surfactants have been studied. The obtained samples were applied in the field of non-enzymatic glucose detection. The electrochemical response characteristics of the modified electrodes toward glucose were investigated by cyclic voltammetry (CV) and chronoamperometry (CA). The electrode modified with C-Cu2O (obtained by using CTAB as surfactant) shared the highest sensitivity of 3123 μAmM−1 cm-2, whereas, the electrode modified with S-Cu2O (obtained by using SDBS as surfactant) exhibited the lowest LOD of 0.87 μM and the widest linear range of 0.05–10.65 mM. All obtained sensors showed fast response to the addition of glucose. The obtained electrodes showed better responses to glucose than other coexisting interferences, indicating that the obtained electrodes had the acceptable selectivity to glucose. In addition, the stability for 5 consecutive weeks had also been studied and exhibited satisfactory results. The obtained electrode was also used to detect the glucose content in real serum. The acceptable selectivity, stability together with the excellent sensing ability in real serum make the obtained electrodes a potential for practical applications.

Rational synthesis of uniform yolk–shell Ni–Fe bimetallic sulfide nanoflakes@porous carbon nanospheres as advanced anodes for high-performance potassium-/sodium-ion batteries

• Unique yolk–shell Ni–Fe sulfide@carbon is designed as an anode for K + / Na + batteries. • Such rational architecture offers enough spaces to buffer volume change of sulfides. • Mesoporous carbon shell improves electron transport rate and structural robustness. • NFS@C yolk-shell anodes exhibit enhanced K + / Na + storage performances. The identification of electrode materials suitable for hosting both K + and Na + is more challenging than that for Li + due to the larger ionic radii of K + and Na + . Thus, the design and fabrication of advanced electrode materials with excellent electrochemical properties for both potassium-ion batteries (KIBs) and sodium-ion batteries (SIBs) is extremely challenging. Herein, a unique yolk–shell-structured Ni–Fe bimetallic sulfide nanoflake@carbon nanosphere (NFS@C) is designed as a high-performance anode for both KIBs and SIBs via a combination of the infiltration method and sulfidation process. During the first infiltration process under vacuum, Ni and Fe precursors can easily penetrate though the shell into the central void of HMCSs with the help of capillary force. The subsequent sulfidation can transform these precursors into their corresponding sulfides, resulting in the formation of NFS@C yolk–shell nanospheres. These rationally engineered architectures provide enough space to buffer the huge volume expansion of Ni–Fe sulfides upon cycling and supply ample channels for the diffusion of ions, thus providing a well-defined conductive network in the entire electrode. Therefore, NFS@C yolk–shell nanospheres exhibit excellent cycling stability (297 mA h g −1 at 0.1 A g −1 after 250 cycles) and rate capability (52 mA h g −1 at 7.0 A g −1 ) for potassium storage. Furthermore, NFS@C nanospheres as anodes for SIBs exhibited high discharge capacity (417 mA h g −1 at 0.2 A g −1 after 250 cycles) and stable capacity (140 mA h g −1 ) even at a high current density (10.0 A g −1 ).