Bulk Interface Research Articles

A Design Strategy for Low-Cost Single/Dual-Band Photodetector: Bulk Heterojunction and Interface Engineering.

Photodetectors (PDs) with band selection functions are highly desirable for the future complex environment. Currently, band-selective PDs are typically realized by integrating various optical filters with broadband PDs or constructing heterojunction with multi-photo-absorbing layers. However, these methods cause increased manufacturing costs and device integration complexity. Here, a novel solution-processed perovskite bulk heterojunction (BHJ) layer (MAPbI3:MA3Bi2I9) is developed as photo-absorbing layer, and an effective interface engineering is proposed to selectively shield photo-generated carriers in the BHJ. By regulating the bias voltage, the tunneling probability of photo-generated carrier of MAPbI3 in the BHJ layer can be easily controlled, enabling band-selective capability. The PD exhibits a superior photo-response in the visible and near-infrared region at the -0.3V, with responsivity of 26.5 and 70.2mAW-1 for 500 and 740nm, respectively. But, at the 0.1V, the PD responds only to the visible region with a photo-response of 3.7mAW-1 (500nm) and maintains a high rejection ratio (R500 nm/R740 nm) of 28.5. This PD also exhibits a fast response speed (rise time: 220µs, fall time: 240µs). This work provides a novel strategy to fabricate a cost-effective multifunctional photodetector for future advanced optoelectronic system.

Bridging Electrolyte Bulk and Interfacial Chemistry: Dynamic Protective Strategy Enable Ultra‐Long Lifespan Aqueous Zinc Batteries

The main bottleneck of rechargeable aqueous zinc batteries (AZBs) is their limited cycle lifespans stemming from the unhealthy electrolyte bulk and fragile interface, especially in the absence of dynamic protection mechanism between them. To overcome this limitation, benefitting from their synergistic physical and chemical properties, chitin nanocrystals (ChNCs) are employed as superior colloid electrolyte to bridge electrolyte bulk and interfacial chemistry for ultra‐long lifespan AZBs. This unique strategy not only enables continuous optimization of the electrolyte bulk and interfacial chemistry within the battery but also facilitates self‐repairing of mechanical damage both internally and externally, thereby achieving comprehensive, persistent, and dynamic protection. As a result, the modified Zinc (Zn) symmetric cells present high Zn plating/stripping coulombic efficiencies of 97.71% ~ 99.81% from 5 to 100 mA cm‐2, and remarkably service lifespan up to 8,200 h (more than 11 months). Additionally, the Zn//MnO2 full cell exhibits a high capacity retention of 70.1% after 3,000 cycles at 5 A g‐1. This dynamic protective strategy to challenge aqueous Zn chemistry may open up a new avenue for building better AZBs and beyond.

Bridging Electrolyte Bulk and Interfacial Chemistry: Dynamic Protective Strategy Enable Ultra-Long Lifespan Aqueous Zinc Batteries.

The main bottleneck of rechargeable aqueous zinc batteries (AZBs) is their limited cycle lifespans stemming from the unhealthy electrolyte bulk and fragile interface, especially in the absence of dynamic protection mechanism between them. To overcome this limitation, benefitting from their synergistic physical and chemical properties, chitin nanocrystals (ChNCs) are employed as superior colloid electrolyte to bridge electrolyte bulk and interfacial chemistry for ultra-long lifespan AZBs. This unique strategy not only enables continuous optimization of the electrolyte bulk and interfacial chemistry within the battery but also facilitates self-repairing of mechanical damage both internally and externally, thereby achieving comprehensive, persistent, and dynamic protection. As a result, the modified Zinc (Zn) symmetric cells present high Zn plating/stripping coulombic efficiencies of 97.71% ~ 99.81% from 5 to 100 mA cm-2, and remarkably service lifespan up to 8,200 h (more than 11 months). Additionally, the Zn//MnO2 full cell exhibits a high capacity retention of 70.1% after 3,000 cycles at 5 A g-1. This dynamic protective strategy to challenge aqueous Zn chemistry may open up a new avenue for building better AZBs and beyond.

The influence of the shock-to-reshock time on the Richtmyer–Meshkov instability in reshock

Experiments on the Richtmyer–Meshkov instability (RMI) in a dual driver vertical shock tube (DDVST) are described. An initially planar, stably stratified membraneless interface is formed by flowing air from above and sulfur hexafluoride from below the interface location using the method of Jones & Jacobs (Phys. Fluids, vol. 9, issue 1997, 1997, pp. 3078–3085). A random three-dimensional, multi-modal initial perturbation is imposed by vertically oscillating the gas column to produce Faraday waves. The DDVST design generates two shock waves, one originating above and one below the interface, with these shocks having independently controllable strengths and interface arrival times. The shock waves have nominal strengths of $M_L=1.17$ and $M_H=1.18$ for the shock wave originating in the light and heavy gas, respectively, with these strengths chosen to result in arrested bulk interface motion following reshock. The influence of the length of the shock-to-reshock time, as well as the order of shock arrival, on the post-reshock RMI is examined. The mixing layer width grows according to $h\propto t^\theta$ , where $\theta _H=0.36\pm 0.018$ (95 %) and $\theta _L=0.38\pm 0.02$ (95 %) for heavy and light shock first experiments, respectively, indicating no strong dependence on the order of shock wave arrival. Volume integrated specific turbulent kinetic energy (TKE) in the mixing layer versus time is found to decay according to $E_{tot}/\bar {\rho }\propto t^p$ with $p_H=-0.823\pm 0.06$ (95 %) and $p_L=-1.061\pm 0.032$ (95 %) for heavy and light shock first experiments, respectively. Notably, the 95 % confidence intervals do not overlap. Analysis on the influence of the shock-to-reshock time on turbulent length scales, transition criteria, spectra and mixing layer anisotropy are also presented.

Over 10% Efficiency Pure Sulfide Kesterite Solar Cells on Transparent Electrode with Cd-Ag Co-Alloying.

The environmentally friendly elements composed of high bandgap pure sulfide Cu2ZnSnS4 (CZTS) semiconductor has broad prospects for building integrated photovoltaic, double-sided, and semi-transparent solar cells when fabricated on transparent substrates. The key issues limiting the performance of CZTS solar cells are poor absorber quality and unfavorable band energy alignment causing serious charge carrier recombination. Here, thefabrication of CZTS solar cells are reported on fluorine-doped tin oxide (FTO) substrates from dimethyl sulfoxide solution and the effects of the Cd and Ag alloying on device performance. Characterizations show that Cd alloying greatly decreases defect concentration and converts Cliff-type band alignment to favorable Spike-type, leading to greatly improved current density. Further, Ag alloying eliminates near-horizontal grain boundaries and passivates defects in both bulk and heterojunction interface, resulting in a champion device with a power conversion efficiency of 10.3%, the highest efficiency pure sulfide CZTS solar cell on FTO substrate. The results demonstrate the great application potential of pure sulfide kesterite solar cells.

On AdS3/ICFT2 with a dynamical scalar field located on the brane

We exploit the holographic duality to study the system of a one-dimensional interface contacting two semi-infinite two-dimensional CFTs. Central to our investigation is the introduction of a dynamical scalar field located on the bulk interface brane which breaks the scaling symmetry of the dual interface field theory, along with its consequential backreaction on the system. We define an interface entropy from holographic entanglement entropy, to construct a g-function. At zero temperature we construct several illustrative examples and consistently observe that the g-theorem is always satisfied. These examples also reveal distinct features of the interface entropy that are intricately linked to the scalar potential profiles. At finite temperature we find that the dynamical scalar field enables the bulk theory to have new configurations which would be infeasible solely with a tension term on the interface brane.

Onset and propagation of slip at adhesive elastic interfaces.

The transition from static to dynamic friction when an elastic body is slid over another is now known to result from the motion of interface rupture fronts. These fronts may be either cracklike or pulselike, with the latter involving reattachment in the wake of the front. How and why these fronts occur remains a subject of active theoretical and experimental investigation, especially given its wide ranging implications. In this work, we investigate the role of boundary loading in answering this question using an elastic lattice-network model under displacement/velocity controlled loading. Bulk elastic and interface bonds are simulated using a network of springs, with a stretch-based detachment and reattachment rule applied to interface bonds. We find that, contrary to commonly used rigid body models with Coulomb-type friction laws, the type of rupture front observed is very closely linked to the location of the applied boundary displacements. Depending on whether the sliding elastic solid is pulled, pushed or sheared-all equivalent in the rigid case-distinct interface rupture modes can occur. We quantify these rupture modes, evaluate the corresponding interface stresses that lead to their formation, and and study their subsequent propagation dynamics. Our results reveal quantitative analogies between the sliding friction problem and mode II fracture, with attendant wave speeds ranging from slow to Rayleigh. We discuss how these fronts mediate interface motion and implications for the general transition mechanism from static to dynamic friction.

Unveiling the humidity effect and achieving an unprecedented 12% PCE in MAPbBr3 solar cells

Fabricating high-efficiency MAPbBr3 solar cells is challenging due to substantial recombination losses within the perovskite layer and at interfaces with charge transport layers. Here, we investigate the critical role of ambient humidity in improving device performance and stability. We varied humidity levels from dry N2 to 80 % relative humidity (RH) and identified that maintaining the environment at 25 % ± 0.82 % RH optimally enhances the morphological, structural, optical properties of MAPbBr3 films. Our novel analyses demonstrate that this specific humidity level significantly reduces bulk defect densities and interface recombination sites without any additive, leads to the formation of larger crystal grains, and improves optical qualities as well. Consequently, devices fabricated under these conditions achieved the highest device efficiency of 12.14 % for the MAPbBr3 solar cells. Additionally, they exhibited remarkable long-term stability, retaining nearly 90 % of the initial efficiency after 1000 h damp-heat and 100 cycles of thermo-cycling tests with encapsulated devices.

Slightly Li-enriched chemistry enabling super stable LiNi0.5Mn0.5O2 cathodes under extreme conditions.

High voltage/high temperature operation aggravates the risk of capacity attenuation and thermal runaway of layered oxide cathodes due to crystal degradation and interfacial instability. A combined strategy of bulk regulation and surface chemistry design is crucial to handle these issues. Here, we present a simultaneous Li2WO4-coated and gradient W-doped 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode through modulating the content of the exotic dopant and stoichiometric lithium salt during lithiation calcination. Benefiting from the slightly Li-enriched chemistry induced by the hetero-epitaxially grown Li2WO4 surface, the 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode demonstrates superior electrochemical performance to W-doped LiNi0.49Mn0.49W0.02O2 and WO3 coated 0.98LiNi0.5Mn0.5O2·0.02WO3 cathodes without a Li-enriched phase. Specifically, when cycled in the potential range of 2.7-4.5 V at 30 °C, the 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode possesses a high discharge capacity of 199.2 and 156.5 mA h g-1 at 0.1 and 5C and a capacity retention of 92.88% after 300 cycles at 1C. Even at a high cut-off voltage of 4.6 V, it still retains a capacity retention of 91.15% after 200 cycles at 1C and 30 °C. Compared with LiNi0.5Mn0.5O2, the enhanced performance of 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 can be attributed to its robust bulk and stable interface, inhibited lattice oxygen release, and improved Li+ transport kinetics. Our work emphasizes the significance of the slightly Li-enriched chemistry and bulk modulation strategy in stabilizing cathodes and hence unlocks vast possibilities for future cathode design.

Ce-substituted P2-type layered cathode with interfacial/ bulk stability for sodium ion batteries

Addressing a changing energy environment, sodium-ion batteries (SIBs) have emerged as one of the most potentially applicable energy resources in the world. Nevertheless, its further application is hindered owing to high degree of interfacial degradation and structural changes, which caused rapid capacity fading. Herein, a novel Ce modified P2-type layered structure cathode material Na0.67Mn0.8Co0.17Ce0.03O2 @ CeO2 is introduced, the stability of cell is improved by simultaneous bulk doping and surface coating in one scalable step. The doping of Ce4+ increases sodium ion transport rate by shrinking transition metal layer ions and expanding Na layer spacing. Irreversible phase transition can be mitigated from the stronger the bond energy between TM and O, which is conducive to the decrease in the Mn3+/Mn4+ ratio, and suppression of the Jahn−Teller distortion. Besides, the doping of larger radius Ce4+ extends the internal paths of crystal structure, which decreases the barrier of Na+, correspondingly, the Na+ diffusion rate was increased. Meanwhile, the CeO2 coating layer effectively inhibits parasitic reactions on the surface and improves the stability of the interface. Which display excellent capacity with a remarkable retention of 86.9 % after 100 cycles at 0.5 C and outstanding discharge rate performance of 87 mA h g−1 at 20 C. This study provides a simple process to concurrently stabilize the bulk structure and interface for the future application for sodium-ion batteries.

Mitigation of Parasitic and Drift Capacitance-Induced Nonlinear Current Responses for Stable and Sensitive Perovskite X-ray Detectors.

The development of perovskite direct X-ray detectors shows potential for advancing medical imaging and industrial inspection precision. To ensure the optimal energy conversion efficiency of X-rays for reducing radiation doses, it is necessary for perovskites with thicknesses reaching hundreds of micrometers or even several millimeters to be utilized. However, the nonlinear current response becomes uncertain with such high thicknesses. For instance, the prevailing theory regarding the rapid trapping and release of charges by shallow-level defects falls short in explaining the nonlinear current response observed in high-quality single-crystal samples. Moreover, a significant nonlinear current response can degrade the detection performance. Here, we elucidate peculiar parasitic and drift capacitance-induced nonlinear current responses in perovskites, which arise from bulk structural deficiencies and interface junction width variation in addition to shallow-level defects. Both theoretical analysis and experimental findings demonstrate the effective suppression of nonlinear current responses by establishing bulk heterojunctions and refining interface junctions. Consequently, we have successfully developed highly linear current-responsive detectors based on polycrystalline MAPbI3 thick films. Notably, these detectors achieve a record sensitivity of 2.3 × 104 μC·Gyair-1·cm-2 under 100 kVp X-ray irradiation with a low bias of 0.1 V/μm, enabling enduring and high-resolution X-ray imaging for high-density objects. Successful fabrication and testing of a 64 × 64-pixel flat-panel prototype detector affirm the widespread applicability of these strategies in rectifying nonlinear current responses in perovskite-based X-ray detectors.

Tailoring the Alkalinity of SnO2 Colloidal Suspension for High‐Performance and Stable Perovskite Solar Cells

The commercial tin oxide (SnO2) colloidal suspension is widely utilized as an electron transport layer (ETL) in high‐performance perovskite solar cells (PSCs). However, despite significant efforts have been proposed to address bulk transport and interface recombination issues, the PSC efficiency is still limited to around 25%. In this study, the crucial role of the physicochemical characteristics of the SnO2 colloidal suspension in shaping the morphology, electrical properties, and optical properties of the SnO2 ETL is investigated. By controlling the pH value of the SnO2 solution with weak acids such as carbonic acid, the reassembly of metal oxide nanoparticles into smaller sizes with more homogeneous dispersion and dense interconnections is successfully induced. Consequently, the resulting SnO2 ETL exhibits enhanced crystallinity, high conductivity, low surface defects, and high optical transmittance. As a result, the efficiency of the target PSC is increased from 23.10% (control device) to 24.70%. This improvement is attributed to higher voltage, photocurrent, and fill factor compared to the relevant control samples. A similar device improvement using phosphoric acid is observed, indicating that the approach represents a universal technique to further enhance the quality of SnO2 ETL for large‐area, high‐efficiency, and stable PSCs.

Crystal structure and shape selection in the growth of 3D metallic crystallites on layered materials: Fe on MoS2

Nucleation and growth of supported 3D metal clusters or crystallites during deposition on MoS2, or on other weakly-adhering layered materials, can potentially produce diverse growth shapes, and even crystal structures differing from the bulk metal. For Fe deposition on MoS2, SEM and AFM observations reveal three distinct crystallite shapes. By comparison with atomistic structure models incorporating realistic Fe-MoS2 interface structures, we conclude that these are: triangular fcc(111) pyramids with sloped {100} side facets; bcc(110) A-frame tents with sloped {100} side facets; and bcc(110) mesas with vertical {100} and {110} side facets. The following picture is proposed for the competitive formation of clusters and crystallites with different structures: (i) small nanoclusters formed at the onset of deposition exhibit facile fluxional dynamics allowing sampling of different crystal structures and shapes; (ii) sufficient fluxionality implies a Boltzmann distribution of sampled structures, and thus coexistence of different structures follows from the demonstrated similar energies for those structures; (iii) growing clusters reach a threshold size above which the characteristic time scale for restructuring exceeds that for cluster growth. Thereafter, clusters are locked-in to a specific crystal structure and shape as revealed by imaging of larger crystallites. Despite a penalty for fcc(111) over bcc(111) pyramids based on bulk energetics, favorable surface and interface energies makes them preferable for smaller sizes.

Elements gradient doping in Mn-based Li-rich layered oxides for long-life lithium-ion batteries

The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost, high energy density, and good performance at low temperatures, and is the promising choice for energy storage batteries. However, the long-cycling stability of batteries needs to be improved. Herein, the Mn-based Li-rich cathode materials with small amounts of Li2MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability. Then the batteries with a high energy density of 600 Wh kg−1, excellent capacity retention of 99.7 % with low voltage decay of 0.03 mV cycle−1 after 800 cycles, and good rates performances can be achieved. Therefore, the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation, and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.

Stabilizing the bulk phase and interface of layered oxide cathode through Li&B double doping

Layered oxide cathodes have attracted widespread attention due to their high-voltage and high discharge capacity. Nevertheless, the irreversible redox reactions of layered oxide cathode and decomposition of electrolyte at high-voltage greatly reduce the reversibility of the batteries. Herein, we employ a double-doping (Li&B) strategy to enhance the electrochemistry performance of the layered NaNi0.3Fe0.3Mn0.4O2 (NNFM) cathode at high voltage. It proved that the dissolution of the transition metal can be restricted by double doping, and the irreversible phase transition is mitigated even at high voltage. As a result, battery with the double-doping cathode exhibits excellent electrochemistry performance, which achieves a capacity of 175 mAh g−1 at 0.2C, maintaining a capacity retention of approximately 87.3% over 100 cycles at 1C, and demonstrates exceptional rate performance. This work presents a novel insight into the doping technique for the high-performance cathode materials and offers a general method for the high energy Na-ion batteries.

Topological semimetal interface resistivity scaling for vertical interconnect applications

In this work, we explore the electron scattering characteristics at interfaces between normal metals and topological semimetals in bulk as well as in thin film structures. We consider Cu/Ta and CoSi/Ta as representative metal/metal and topological semimetal/metal interface structures, respectively. For bulk interface structures, we find that metal/topological semimetal interfaces have roughly 20× higher interfacial resistivity than normal metal/metal interfaces primarily due to the low electronic density of states, the Fermi level in bulk topological semimetals. For thin films, we find that normal metal/metal interfacial resistivity shows a weak dependence on film thickness and is generally close to the corresponding bulk value. Interfaces between surface-conduction dominated topological semimetals, such as CoSi and normal metals in thin films, however, show decreasing interfacial resistivity with decreasing film thickness. This apparent reduction in interface resistivity originates from the surface-dominated transport, where the total transmission across the interface varies little with reduced film thickness, yielding an effective increase in interface conductivity at smaller dimensions. These results suggest that topological semimetals may be attractive candidates for next-generation interconnect materials with critically small dimensions where interfaces with other metals are ubiquitous.

Double S-scheme Cu2−xSe/twinned-Cd0.5Zn0.5S homo-heterojunctions with surface plasmon effects for efficient photocatalytic H2 evolution

The enhancement of charge separation and utilization efficiency in both the bulk phase and interface of semiconductor photocatalysts, as well as the expansion of light absorption range, are crucial research topics in the field of photocatalysis. To address this issue, twinned Cd0.5Zn0.5S (T-CZS) homojunctions consisting of wurtzite Cd0.5Zn0.5S (WZ-CZS) and zinc blende Cd0.5Zn0.5S (ZB-CZS) were synthesized via a hydrothermal method to facilitate the bulk-phase charge separation. Meanwhile, Cu2−xSe with localized surface plasmon resonance effect (LSPR) generated by Cu vacancies was also obtained through a hydrothermal process. Due to their opposite electronegativity, a solvent evaporation strategy was employed to combine Cu2−xSe and T-CZS by intermolecular electrostatic. After optimization, the photocatalytic hydrogen (H2) evolution rate of 5 wt% Cu2−xSe/T-CZS reached an impressive value of 60 mmol∙h−1∙g−1, which was 4.6 and 66.6 times higher than that of pure Cu2−xSe and T-CZS, respectively. Furthermore, this composites demonstrated a remarkable rate of 0.46 mmol∙h−1∙g−1 under near-infrared (NIR) wavelength (>800 nm). The enhanced performance observed in Cu2−xSe/T-CZS can be attributed to its unique and efficient double S-scheme charge transfer mechanism which effectively suppresses rapid recombination of electron-hole pairs both within the bulk phase and at the surface interfaces; this conclusion is supported by Density Functional Theory (DFT) calculations as well as electron paramagnetic resonance spectroscopy analysis. Moreover, incorporation of Cu2−xSe enables effective utilization ultraviolet visible-near infrared (UV–Vis-NIR) light by the composites while facilitating injection “hot electrons” into T-CZS for promoting photocatalytic reactions. This study provides a potential strategy for achieving efficient solar energy conversion through synergistic integration of non-stoichiometric plasmonic materials with photocatalysts with twinned-twinned structures.

Analysis of the mechanism for enhanced crystalline quality of wide-bandgap Cu(In,Ga)Se2 films by pre-deposited Ag precursor

Wide-bandgap Cu(In,Ga)Se2 (CIGS) solar cells show prospective utility for both single-junction and tandem solar cell applications. However, poor bulk absorber quality and interface recombination limiting the comprehensive utilization of its...

(Invited) Multifunctional Binders for High-Performance Rechargeable Batteries

Secondary battery plays a significant role in our daily life as well as in modern smart grids, which typically consists of an electrolyte and two electrodes determining the key parameters of the battery. Despite a small dose that usually less than 10%, the binder is a crucial component to keep the electrode integrity and ensure the high electrochemical performance. What`s more, the modification of binder could be conducted to alleviate or even eliminate the side effects raised by failure behaviors of the electrode active materials. However, the state-of-the-art binder optimization strategies still fall behind the rapid development of the novel electrode materials.To improve the energy density of secondary batteries, high-capacity electrode materials have been explored, including silicon, sulfur, layered oxides, etc. However, their practical applications are hindered by various failure behaviors. Take Si as an example, though the Si-based anodes exhibit high capacity up to 4200 mA g-1, they undergo huge volumetric expansion (≈400%) during the electrochemical reactions, resulting in the cracking of active material particles, electrode exfoliation, continuous electrolyte consumption and progressive SEI formation. As a consequence, the capacity of Si-based electrode decreases dramatically along with cycling. The conventional binders that have been widely used in the rechargeable battery systems are typically linear polymers, which are unable to endure the high volume change and address other challenges raised by electrode materials such as low conductivity, unstable bulk structure and interface, etc. To increase the mechanical strength and the electrochemical stability of electrodes, the design of multi-functional binders is considered to be an effective strategy to meet various requirements of advanced binders for high-performance batteries simultaneously.In this work, the synthesis and characterization of multifunctional binders for high-capacity electrode materials are demonstrated. By the introduction of intermolecular forces and chemical bonds, 3D networks are constructed and the ability for volume change accommodation are enhanced as well as the binding force. Moreover, the dynamic crossed links also endow the binders with self-healing ability, which could help to remedy the cracking issues in the advanced electrode materials. Due to the merits of the as-synthesized binders, the electrochemcial performance of the high-capacity electrode is significantly improved, demonstrating a promising strategy for next-generation energy storage systems.

Realization High-Voltage Stabilization of O3-Type Layered Oxide Cathodes for Sodium-Ion Batteries by Sn Simultaneously Dual Modification

The total global production of lithium-ion batteries (LIBs) used in electric vehicles and stationary energy storage devices has increased sharply to reach the targeted Net Zero by 2050. This leads to concerns about the future and long-term availability and cost of critical raw materials (cobalt, nickel, lithium and copper) employed in LIBs. Therefore, alternative new-generation batteries with comparable performance but using less critical raw materials are needed.Sodium-ion Batteries (NIBs) offer a wealth of possibilities for inexpensive and sustainable energy storage devices. To maximize their potential, new cathode materials with high energy densities and stable structures are required. Cobalt-free sodium transition metal oxides of O3 type are a predominant cathode for NIBs due to their appreciable specific capacity, reduction in the use of critical elements, and the potential to rival LiFePO4 in terms of energy density. However, rapid capacity fading caused by serious structural and interfacial degradation hamper this process.Herein, we provide a novel Sn-modified O3-type NaNi1/3Fe1/3Mn1/3O2 cathode with improved high-voltage stability by bulk Sn doping and surface coating simultaneously. The bulk substitution of Sn4+ stabilizes the crystal structure by alleviating the irreversible high voltage phase transition and lattice structure degradation. In the meantime, the spontaneously formed tin rich surface layer effectively inhibits surface parasitic reactions and improves interfacial stability during cycling. As a result, the Sn-modified NaNi1/3Fe1/3Mn1/3O2 cathode exhibited excellent cycling performance by an almost doubled capacity retention increase after 200 cycles within 2.0-4.1V. The influence of Sn modification on the crystal structure and electrochemical properties has been investigated for the first time, and the mechanism was studied through an extensive analysis by in situ XRD, HRTEM, FIB-SEM, XPS and Mössbauer spectroscopy.This work offers an industrially feasible strategy to simultaneously stabilize the bulk structure and interface for O3-type layered cathodes for SIBs and raises the possibility of similar effective strategies to be employed for other energy storage materials Figure 1