Na-Se Batteries Research Articles

Encapsulation of Se into Cu-decorated MXene nanosheets with superior electrochemical performance for advanced Na-Se batteries

Sodium-selenium (Na-Se) batteries are promising energy storage systems with high energy density, high safety, and low cost. However, the huge volume change of selenium, the dissolution shuttle of polyselenides, and low selenium loading need to be solved. Herein, Cu nanoparticles decorated MXene nanosheets composite (MXene/Cu) are synthesized by etching Ti3AlC2 using a molten salt etching strategy. The Se-loaded MXene/Cu (Se@MXene/Cu) electrode delivers superior electrochemical performance even with a high Se loading of ∼74.3 wt%, owing to the synergistic effect of the two-dimensional (2D) confined structure and catalytic role of the unique MXene/Cu host. Specifically, the obtained electrode provides a reversible capacity of 587.3 mAh/g at 0.2 A/g, a discharge capacity as high as 511.3 mAh/g at a high rate of 50 A/g, and still maintains a capacity of 471.9 mAh/g even after 5000 cycles based on the mass of Se@MXene/Cu. With such excellent electrochemical kinetic properties, this study highlights the importance of designing various MXene-based composites with synergistic effects of 2D confined structure and Cu catalytic center for the development of high-performance alkali metal–chalcogen battery systems.

Synthesis of hierarchical porous carbon scaffold derived from red kidney bean peels for advanced Li–Se and Na–Se batteries

Incorporating selenium into high-surface-area carbon with hierarchical pores, derived from red kidney bean peels via simple carbonization/activation, yields a superior Li–Se battery cathode material. This method produces a carbon framework with 568 m2 g−1 surface area, significant pore volume, and improves the composite’s electronic conductivity and stability by mitigating volume changes and reducing lithium polyselenide dissolution. The Se@ACRKB composite, containing 45 wt% selenium, shows high discharge capacities (609.13 mAh g−1 on the 2nd cycle, maintaining 470.76 mAh g−1 after 400 cycles at 0.2 C, and 387.58 mAh g−1 over 1000 cycles at 1 C). This demonstrates exceptional long-term stability and performance, also applicable to Na–Se batteries, with 421.36 mAh g−1 capacity after 200 cycles at 0.1 C. Our study showcases the potential of using sustainable materials for advanced battery technologies, emphasizing cost-effective and scalable solutions for energy storage.

High Selenium Loading in Vertically Aligned Porous Carbon Framework with Visualized Fast Kinetics for Enhanced Lithium/Sodium Storage

AbstractLithium/sodium–selenium (Li/Na–Se) batteries with high volumetric specific capacity are considered promising as next‐generation battery technologies. However, their practical application is hindered by challenges such as low Se loading in cathodes and the polyselenides shuttle effect. To address these challenges, a new Se host is introduced in the form of a free‐standing N, O co‐doped vertically aligned porous carbon framework decorated with a carbon nanotube forest (VCF‐CNTs), allowing for high mass loading of up to 16 mg cm−2. The low‐tortuosity Se@VCF‐CNTs architecture facilitates rapid lithiation/sodiation kinetics, while the CNT forests in vertical microchannels enhance efficient Se loading and serve as a multi‐layer fence to prevent undesired polyselenide shuttling. Consequently, the Se@VCF‐CNTs cathode displays a significant areal capacity of 10.3 mAh cm−2 at 0.1 C with a Se loading of 16 mg cm−2 for Li–Se batteries, exceeding that of commercial lithium ion batteries (4.0 mAh cm−2). In Na–Se batteries, the Se@VCF‐CNTs electrode with a Se loading of 5 mg cm−2 exhibits a discharge capacity of 436 mAh g−1 after 200 cycles, proving its consistent cycling performance. This study enriches the field of knowledge concerning high‐loading Se‐based battery systems, offering a promising avenue for enhancing energy density in the field.

From longan peel waste to energy storage: Porous activated carbon as a cathode matrix for advanced Li/Na-selenium batteries

This paper explores the potential of Longan peel waste (LPw) as a sustainable and cost-effective matrix for selenium-based cathodes in Li-Se and Na-Se batteries. Following activation, we created LP2—a designation for the carbon precursor derived from LPw, activated at a 1:2 ratio of carbonized LPw to KOH. This nomenclature, where ‘LP' stands for ‘Longan peel' and ‘2′ reflects the optimization of this ratio, led to a hierarchical porous structure with an average pore size of 3.0307 ​nm and a significant BET surface area of 111.9386 ​m2 ​g-1. Selenium was incorporated into the LP2 matrix using a simple melt diffusion technique, yielding the composite Se@LP2. In Li-Se batteries, Se@LP2 exhibited an initial discharge capacity of 1033.75 mAh g⁻1 ​at 0.1C. At a 1C rate, the composite demonstrated a capacity retention of 301.14 mAh g⁻1 after 550 cycles and 380.91 mAh g⁻1 after 100 cycles. Moreover, for Na-Se batteries, the composite showcased a capacity retention of 347.18 mAh g⁻1 after 100 cycles at 0.1C. These findings underscore LP2's potential as a viable and efficient matrix for selenium-based cathodes, revealing promising prospects for the advancement of highly efficient Li-Se and Na-Se batteries.

Iron nanoparticles surface decorated MXene via molten salts etching as selenium host for ultrafast sodium ion storage

Sodium-selenium (Na-Se) batteries have gained attention due to their high energy density and power density, resulting from the liquid–liquid reaction at the interface in the dimethoxyethane electrolyte. Nevertheless, the pronounced shuttle effect of polyselenides causes low coulomb efficiency and inadequate cycling stability for Na-Se batteries. Herein, the iron nanoparticles surface modified accordion-like Ti3C2Tx MXene (MXene/Fe) synthesized via the molten salt etching is utilized as the host of Se species for high-performance Na-Se battery cathode. Benefiting from the layered structure and chemical adsorption of accordion-like MXene, the shuttle effect of the cathode is effectively inhibited. Simultaneously, electrochemical kinetics is boosted due to the catalytic effect of Fe nanoparticles, which facilitate the transformation of polyselenide from long-chain to short-chain, contributing to pseudocapacitive capacity. Consequently, the Se-based cathode delivers a steady capacity of 575.0 mA h g−1 at 0.2 A/g, and even a high capacity of 500 mAh/g at 50 A/g based on the mass of Se@MXene/Fe electrode, indicating the ultrafast Na+ ion storage. Most notably, this structure demonstrated remarkable long-term cycling stability for 5000 cycles with a high capacity retention of 97.4 %. The electrochemical energy storage mechanism is further revealed by in situ Raman. Herein, the confinement-catalysis structure shines light on inhibiting shuttling and facilitating ultrafast ion storage.

Theoretical insights into single-atom catalysts for improved charging and discharging kinetics of Na-S and Na-Se batteries.

Dissolution of poly-sulfide/selenides (p-S/Ses) intermediates into electrolytes, commonly known as the shuttle effect, has posed a significant challenge in the development of more efficient and reliable Na-S/Se batteries. Single-atom catalysts (SACs) play a crucial role in mitigating the shuttling of Na-pS/Ses and in promoting Na2S/Se redox processes at the cathode. In this work, single transition metal atoms Co, Fe, Ir, Ni, Pd, Pt, and Rh supported in nitrogen-deficient graphitic carbon nitride (rg-C3N4) are investigated to explore the charging and discharging kinetics of Na-S and Na-Se batteries using Density Functional Theory calculations. We find that SAs adsorbed on reduced g-C3N4 monolayers are substantially more effective in trapping higher-order Na2Xn than pristine g-C3N4 surfaces. Moreover, our ab initio molecular dynamics calculations indicate that the structure of X8 (X = S, Se) remains almost intact when adsorbed on Fe, Co, Ir, Ni, Pt, and Rh SACs, suggesting that there is no significant S or Se poisoning in these cases. Additionally, SACs reduce the free energies of the rate-determining step during discharge and present a lower decomposition barrier of Na2X during charging of Na-X electrode. The underlying mechanisms behind this fast kinetics are thoroughly examined using charge transfer, bonding strength, and d-band center analysis. Our work demonstrates an effective strategy for designing single-atom catalysts and offers solutions to the performance constraints caused by the shuttle effect in sodium-sulfur and sodium-selenium batteries.

Sodium-Selenium Batteries with Outstanding Rate Capability by Introducing Cubic Mn2 O3 Electrocatalyst.

With their high volumetric capacity and electronic conductivity, sodium-selenium (Na-Se) batteries have attracted attention for advanced battery systems. However, the irreversible deposition of sodium selenide (Na2 Se) results in rapid capacity degradation and poor Coulombic efficiency. To address these issues, cubic α-Mn2 O3 is introduced herein as an electrocatalyst to effectively catalyze Na2 Se conversion and improve the utilization of active materials. The results show that the addition of 10 wt% Mn2 O3 in the selenium/Ketjen black (Se/KB) composite enhances the conversion from Na2 Se to Se by lowering activation energy barrier and leads to fast sodium-ion kinetics and low internal resistance. Consequently, the Mn2 O3 -based composite delivers a high specific capacity of 635 mAh ⋅ g-1 at 675 mA ⋅ g-1 after 250 cycles as well as excellent cycling stability for 800 cycles with a high specific capacity of 317 mAh ⋅ g-1 even at the high current density of 3375 mA ⋅ g-1 . Due to the cubic Mn2 O3 electrocatalyst, the performance of the composites is superior to existing state-of-the-art Na-Se batteries reported in the literature.

Direct Observation of the Evolutionary Process in Room-Temperature Sodium-Sulfur/Selenium Batteries Using operando Light Microscopy.

Understanding the conversion mechanism of active materials in the electrode is essential to guide the design of room-temperature sodium-sulfur/selenium (RT Na-S/Se) batteries. However, there is still some confusion regarding the dissolution and formation of the insulating active particles. Conventional detection methods have difficulty in capturing and presenting the dynamic processes of these microscopic particles in the "black box" battery. In this study, a visualization technique was applied to track and monitor the internal evolution process of RT Na-S/Se batteries, visualizing the dissolution and formation details of insulating solid particles in real time. Supercooled liquid sulfur and spherulites were also observed for the first time in this system. The microstructural evolution mechanism is inferred based on the observation of the dynamic information on microscopic particles. This paper provides insights into the internal workings of RT Na-S and Na-Se batteries, allowing for a more comprehensive and in-depth understanding of their dynamics.

Tetrahedral Bonding Structure (Ni3 -Se) Induced by Lattice-Distortion of Ni to Achieve High Catalytic Activity in Na-Se Battery.

Fabrication of transition-metal catalytic materials is regarded as a promising strategy for developing high-performance sodium-selenium (Na-Se) batteries. However, more systematic explorations are further demanded to find out how their bonding interactions and electronic structures canaffect the Na storage process. This study finds that lattice-distorted nickel (Ni) structure canform different bonding structures with Na2 Se4 , providing high activity to catalyze the electrochemical reactions in Na-Se batteries. Using this Ni structure to prepare electrode (Se@NiSe2 /Ni/CTs) canrealize rapid charge transfer and high cycle stability of the battery. The electrode exhibits high storage performance of Na+ ; i.e., 345 mAhg⁻1 at 1 C after 400 cycles, and 286.4 mAhg⁻1 at 10 C in rate performance test. Further results reveal the existence of a regulated electronic structure with upshifts of the d-band center in the distorted Ni structure. This regulation changes the interaction between Ni and Na2 Se4 to form a Ni3 -Se tetrahedral bonding structure. This bonding structure canprovide higher adsorption energy of Ni to Na2 Se4 to facilitate the redox reaction of Na2 Se4 during the electrochemical process. This study can inspire the design of bonding structure with high performance in conversion-reaction-based batteries.

Tetraiodo nickel phthalocyanine electrocatalyst enables superior Na–Se battery performances by enhancing the utilization of Na2Se

Sodium–Selenium (Na–Se) batteries are regarded as one of the most promising alternative energy storage devices compared to their room-temperature sodium-sulfur battery counterparts. Since Selenium cathodes operate well in carbonate-based electrolytes, the solubility issue of polyselenides is no longer an issue. However, the main obstacles of Na–Se batteries remain the precipitation and reoxidation of sodium selenide (Na2Se) owing to the high energy barrier of these reactions and passivation of the electrode during cycling. Herein, we propose a tetraiodo nickel phthalocyanine (NiPc) electrocatalyst to improve the electrochemical performance of Na–Se batteries. It is demonstrated that the presence of even a small amount of NiPc improves the electrocatalytic conversion of Na2Se by lowering the decomposition energy barrier of Na2Se. The improved cell performances are verified by the decrease in reaction polarization, Tafel slope values, and the measured internal resistance of Na–Se cells in addition to the density functional theory (DFT) calculations. Consequently, the Na–Se cell with the NiPc electrocatalyst exhibited outstanding rate capability (405 mAh∙g−1 after 250 cycles at 3375 mA g−1 and superior long-term cyclic stability (563 mAh∙g−1 after 250 cycles at 675 mA g−1), which are among the most promising rate performance characteristics demonstrated in the literature.

Micropore engineering on hollow nanospheres for ultra-stable sodium-selenium batteries

Attracted by high energy density and considerable conductivity of selenium (Se), Na-Se batteries have been deemed promising energy-storage systems. But, it still suffers from sluggish kinetic behaviors and similar “shuttling effect” to S-electrodes. Herein, utilizing uniform hollow carbon spheres as precursors, Se-material is effectively loaded through vapor-infiltration method. Owing to the distribution of optimized pores, the content of microspores could be up to ∼60% (<2 nm), serving important roles for the physical confinement effect. Meanwhile, the rich oxygen-containing groups and N-elements could be noted, inducing the evolution of electron-moving behaviors. More significantly, assisted by the interfacial C–Se bonds and tiny Se distributions, Se electrodes are activated during cycling. Used as cathodes for Na-Se systems, the as-resulted samples display a capacity of 593.9 mA h g−1 after 100 cycles at the current density of 0.1 C. Even after 6000 cycles, the capacity could be still kept at about 225 mA h g−1 at 5.0 C. Supported by the detailed kinetic analysis, the designed microspores size induces the increasing redox reaction of nano Se, whilst the surface traits further render the enhancement of pseudo-capacitive contributions. Moreover, after cycling, the product Sex (x < 4) in pores serves as the primary active material. Given this, the work is anticipated to provide an effective strategy for advanced electrodes for Na-Se systems.

Rational design of MXene-based single atom catalysts for Na-Se batteries from sabatier principle.

Na-Se batteries have attracted great attention because of their high-energy density and low cost, though the shuttle effect of polyselenides and sluggish reaction dynamics still limit their practical applications. Herein, MXenes were decorated with single zinc atom as selenium hosts, and the effect of interfacial electrochemical reaction was studied via first-principles simulation. The embedding of single zinc atom into MXenes was found to enhance the anchoring ability to inhibit the shuttle effect. However, Zn-MXenes as single atom catalysts had different effects on interfacial electrochemical reactions, which can be attributed to the increased interaction strengths between Zn-MXenes and polyselenides. For Ti-based MXenes, the enhanced interaction was found to be beneficial for the electrochemical reaction, whereas the overly strong anchoring strength of Zn-Cr2CO2 would inhibit charging-discharging kinetics. Therefore, the matching of MXenes and metal atoms should be considered to adjust the anchoring ability based on the Sabatier principle. This work provides new insights into the design of SACs and high-performance Na-Se batteries.

Orthorhombic Nb2 O5 Decorated Carbon Nanoreactors Enable Bidirectionally Regulated Redox Behaviors in Room-Temperature Na-S Batteries.

Regulating redox kinetics is able to spur the great-leap-forward development of room-temperature sodium-sulfur (RT Na-S) batteries, especially on propelling their Na-ion storage capability. Here, an innovative metal oxide kinetics accelerator, orthorhombic Nb2 O5 Na-ion conductor, is proposed to functionalize porous carbon nanoreactors (CNR) for S cathodes. The Nb2 O5 is shown to chemically immobilize sodium polysulfides via strong affinity. Theoretical and experimental evidence reveals that the Nb2 O5 can bidirectionally regulate redox behaviors of S cathodes, which accelerates reduction conversions from polysulfides to sulfides as well as promotes oxidation reactions from sulfides to S. In situ and ex situ characterization techniques further verify its electrochemical lasting endurance in catalyzing S conversions. The well-designed S cathode demonstrates a high specific capacity of 1377mA h g-1 at 0.1 A g-1 , outstanding rate capability of 405mA h g-1 at 2 A g-1 , and stable cyclability with a capacity retention of 617mA h g-1 over 600 cycles at 0.5 A g-1 . An ultralow capacity decay rate of 0.0193% per cycle is successfully realized, superior to those of current state-of-the-art RT Na-S batteries. This design also suits emerging Na-Se batteries, which contribute to outstanding electrochemical performance as well.

Atomically dispersed Co-N4C2 catalytic sites for wide-temperature Na-Se batteries

Sodium-selenium (Na-Se) batteries have been widely regarded as promising large-scale energy storage systems owing to the high volumetric energy density of 2530 W h L−1 and natural abundance of the element sodium. However, critical drawbacks including sluggish redox kinetics, severe volume variation and shuttle effect seriously deteriorate the electrochemical performance. Herein, we propose a precompetitive coordination strategy for over-coordinated single-atom catalyst, and subsequently synthesize the six-coordinated Co electrocatalyst supported carbon nanofibers (Co-N4C2) for solid-state conversion in wide-temperature Na-Se batteries. The Co-N4C2 catalyst can not only boost the redox kinetics of solid-phase Na2Se2/Na2Se, but also accelerate the electroreduction of ethylene carbonate to construct robust cathode electrolyte interphase, thereby inhibiting the irreversible phase transformation of active Se species. Furthermore, for the first time, the components of the cathode electrolyte interphase as sodium ethylene mono-carbonate are identified. Consequently, the as-synthesized free-standing Se@Co-N4C2 cathode with high Se-loading realizes high capacity, cycling stability and rate capability at both room temperature (20.0/40.0 ℃) and low temperature (− 11.7 ℃).

Dual-functional hosts derived from metal-organic frameworks reduce dissolution of polyselenides and inhibit dendrite growth in a sodium-selenium battery

Selenium-based cathodes for sodium-ion batteries have attracted considerable attention due to their high electronic conductivity and volumetric capacity compared to sulfur-based cathodes. However, the use of sodium-selenium batteries has been hindered due to the low selenium reaction activity towards sodium, rapid capacity fading caused by the shuttle effect of polyselenides, and the formation of sodium dendrites on the Na anodes. Herein, starting from the nitrogen and oxygen-containing ligands, two precursors of Ni&Zn-MOF and Zn-MOF were used to fabricate the cathode and anode, respectively. A N,O-codoped porous carbon host decorated with well-dispersed Ni single-atom catalyst was derived from the Ni&Zn-MOF for Se storage. When applied as a cathode in Na-Se batteries, this composite accelerated the reaction kinetics of Se and Na+, and at the same time weakened the Se-Se bond owing to its high adsorption to the Se8 ring, which resulted in a significant improvement of the cycle stability. Meanwhile, a dendrite-free anode was realized by using Zn-MOF derived N,O-codoped porous carbon host, which showed a strong sodiophilic ability for Na metal. As a result, the Na-Se battery employing these two composites as the cathode and anode showed an excellent cycle stability and improved safety.

Rationally designed oxygen vacancy for achieving effective and kinetically boosted Na-Se batteries

Reasonable chemistry design of selenium hosts to stabilize and transform sodium polyselenide (Na2Sex) is of great significance for high-performance Na-Se batteries. Herein, a hollow nitrogen-doped carbon embedded with oxygen defective Fe2O3 nanoparticles (Fe2O3@NC) has been prepared, which integrates conductivity, polarity and catalytic ability into cooperation and is validated as a suitable selenium host to suppress the Na2Sex shuttling. Fe2O3 not only serves as an efficient Na2Sex reservoir via strong chemisorption between O atoms of Fe2O3 and Na atoms of Na2Sex, but also promotes the transformation of Na2Sex. Moreover, the plentiful oxygen vacancy defects in Fe2O3 phase increases the catalytic conversion efficiency of Na2Sex. Accordingly, the selenium-containing Fe2O3@NC exhibits a reversible capacity of 215.3 mAh g−1 after 2310 cycles at 10 A g−1 with a superior capacity retention of 97.1%. This work clarifies the unique chemical properties of metal oxides, especially analogs with plentiful O vacancies, in promoting the adsorption-conversion process of Na2Sex, which provides a practical way to achieve the design of highly stable Na-Se batteries.

Rational design of 3D hierarchical MOFs-derived hollow porous carbon/Ni(OH)2 nanosheet for long-cycle Li/Na–Se batteries

Over the years, selenium has caught the attention on its merits, high electronic conductivity, high melting point, and high energy capacity. Nevertheless, the enormous volumetric expansion and shuttle effects of polyselenides simultaneously hinder selenium application. We report a three-dimensional hierarchical structure composed of porous carbon layers derived from the metal-organic framework with Ni(OH)2 nanosheet shell as selenium host. The 3D hierarchical structure looks like slices of toast stacked on top of each other and decorated with Ni(OH)2 nanosheets. The toast improves the electronic conductivity of selenium and serves as a shelter to provide sufficient free space for volume change. The Ni(OH)2 nanosheet shell act as a functional protective barrier to restrain the shuttle effects and achieve a shorter ion transport path. Consequently, the Li–Se batteries deliver remarkable cyclic performance over 2500 cycles at 3 C with 0.018% capacity decay due to the unique structure. In addition, the electrode also performs well in Na–Se batteries.

Investigating role of ammonia in nitrogen-doping and suppressing polyselenide shuttle effect in Na-Se batteries

Sodium-ion battery (SIB) has attracted extensive research attention owing to its high theoretical capacity and low cost. Herein, we synthesize bio-waste-derived activated carbon (BAC) through a facile synthesis process followed by selenium loading (using melt-infusion method) to form BAC@Se composites. The synthesized BAC and its composite BAC@Se revealed excellent rate performance, great cycling stability, and good reversibility. The BAC revealed a maximum specific capacity of 257 mAh/g at 20 mA/g current density. The BAC@Se showed the maximum specific capacity of 701 mAh/g at 50 mA/g current density (equivalent to a specific energy of about 1051 WhKg−1/75 WKg−1) and good rate performance with 226 mAh/g specific capacity at a high current density of 2500 mA/g. Moreover, the composite revealed good cycling stability by retaining 348 mAh/g capacity at 500 mA/g after 500 cycles. The excellent electrochemical properties were attributed to the unique design of composites, which not only provided the physio-chemically trapped selenium but also ensure the fast kinetics of Na ions through interconnected 3-D channels and high restrain against the dissolution of polyselenides into an electrolyte. This work may shed light on recycling different bio-wastes into energy materials for energy storage devices.

Constructing durable ultra-high loading and areal capacity lithium/sodium-selenium batteries via a robust aqueous network binder

An aqueous robust network binder is designed by ionic cross-linking reaction to coat Se cathode for the first time, achieving admirable stability of the electrode, thus ultra-high Se loading and areal capacities for Li-Se and Na-Se batteries. • An aqueous robust network binder (Fe@SA) is designed by ionic cross-linking reaction to coat Se cathode for the first time. • Enhanced electrode stability by Fe@SA binder brings excellent electrochemical performance for Se cathode batteries. • An ultra-high Se loading cathode is obtained by Fe@SA binder with traditional blade coating technology. • Fe@SA binder can achieve an ultra-high reversible areal capacity of 4.9 mAh cm −2 for Li-Se battery. • The highest reversible areal capacity of 5.6 mAh cm −2 for Na-Se battery can be obtained with Fe@SA binder. Selenium is a considerable energy storage material, with presenting a one-step electrochemical reaction in a cheap carbonate-based electrolyte and providing a considerable capacity as a cathode. However, capacity loss and safety issues caused by volume changes during charge and discharge processes, as well as low mass loading, still hinder the practical development of selenium cathodes. Binder is one of the indispensable constitutions of the electrode and crucial for improving the electrochemical performance of the battery. Herein, we design an aqueous robust network binder by doping a trace amount of Fe 3+ ions into sodium alginate for durable lithium/sodium-selenium batteries for the first time. With the modified binder, the capacity of the battery is increased by more than 17% at a current of 0.2C. Furthermore, it can achieve the highest Se loading made by blade coating of up to 12 mg cm −2 , which brings ultra-high reversible areal capacity of 4.9 mAh cm −2 for lithium-selenium battery, and currently the highest reported reversible areal capacity currently of up to 5.6 mAh cm −2 for sodium-selenium battery. Such a well-designed binder can improve the electrochemical performance and areal capacity of selenium cathodes, thereby boosting the practical application of selenium cathodes for energy storage.

Trimodal hierarchical porous carbon nanorods enable high-performance Na-Se batteries.

Technical bottlenecks of polyselenide shuttling and material volume variation significantly hamper the development of emerging sodium-selenium (Na-Se) batteries. The nanopore structure of substrate materials is demonstrated to play a vital role in stabilizing Se cathodes and approaching superior Na-ion storage properties. Herein, an ideal nanorod-like trimodal hierarchical porous carbon (THPC) host is fabricated through a facile one-step carbonization method for advanced Na-Se batteries. The THPC possesses a trimodal nanopore structure encompassing micropores, mesopores, and macropores, and functions as a good accommodator of Se molecules, a reservoir of polyselenide intermediates, a buffer for volume expansion of Se species during sodiation, and a promoter for electron/ion transfer in the electrochemical process. As a result, Na-Se batteries assembled with the Se-THPC composite cathode realize high utilization of Se, fast redox kinetics, and excellent cyclability. Furthermore, the Na-ion storage mechanism of the well-designed Se-THPC composite is profoundly revealed by in situ visual characterization techniques.