Ultralong Lifespan Research Articles

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.

Stabilizing Lithium Metal Anodes by Fiber Clustering.

Lithium metal anodes generally suffer from uncontrolled dendrite growth and large volume change, while traditional skeletons such as Li13In3 and Li22Sn5 are too heavy and discontinuous to offer highly efficient structural supportability for composite Li anodes. In this work, lightweight and stable fiber-clustered skeletons, which are composed of LiB fibers and jointed Li22Si5 nanoparticles, can be obtained by smelting SiB6 powder and Li ingots. In addition to serving as both ionic and electronic conductors for composite Li anodes, the stable skeletons reduced volumetric fluctuation by offering uniform, heterogeneous, and continuous architectures while suppressing lithium dendrites with low nucleation overpotential and diffusion energy barrier. As a result, the Li-SiB6|Li-SiB6 symmetrical cells achieve an ultralong lifespan over 2000 h cycling at 1 mA cm-2 and 1 mA h cm-2. Eventually, the Li-SiB6|LiFePO4 full cells exhibit a long-term cyclability of 400 cycles with a high-capacity retention of 94.5% at 2 C, and the Li-SiB6|LiCoO2 pouch cells exhibit an impressive 85% capacity retention after 350 cycles. This work develops a new strategy to strengthen the stability of fibrous skeletons and minimize volume changes for dendrite-free Li metal anodes.

Emulating "Curvature-Enhanced Adsorbate Coverage" for Superconformal and Orientated Zn Electrodeposition in Zinc-ion-Batteries.

Uneven Zn deposition and unfavorable side reactions have prevented the reversibility of the Zn anode. Herein, we design a rearranged (002) textured Zn anode inspired by a traditional curvature-enhanced adsorbate coverage (CEAC) process to realize the highly reversible Zn anode. The rearranged (002) textured structure directs superconformal Zn deposition by controlling the spatial deposition rate of the rearranged crystal planes, thereby promoting bottom-up "superfilling" of the 3D Zn skeletons. Meanwhile, our designed anode also induces the epitaxial Zn deposition, alleviating the parasitic reactions owing to the lowest surface energy of the (002) plane. Attributed to these superiorities, uniform and oriented Zn deposition can be obtained, exhibiting an ultra-long lifespan over 479 hrs at an ultrahigh depth of discharge (DOD) of 82.12 %. The Zn|Na2V6O16 ⋅ 3H2O battery delivers an improved cycling performance, even at a high area capacity of 5.15 mAh/cm2 with a low negative/positive (N/P) capacity ratio of 1.63. The superconformal deposition approach for Zn anodes paves the way for the practical application of high-performance zinc-ion batteries.

Interface engineering of electron-ion dual transmission channels for ultra-long lifespan quasi-solid zinc-ion batteries

Hydrogel electrolytes have emerged as effective strategies to prolong the lifespan of aqueous zinc ion batteries (AZIBs). However, dendrites and side reactions are still inescapable due to the residual active water and chaotic migration of Zn2+. Herein, a super stable Zn anode is realized through the synergistic effect of interfacial electron-ion dual transmission channels (EIDC) and an intermediate sodium alginate (SA) gel. Specifically, the SA gel can adjust the solvation structure of Zn2+ and weaken the strong bonding of Zn2+ and H2O molecules. The EIDC polymer layer (PEDOT:PSS) is engineered on the SA hydrogel surfaces, in which PSS chains can offer uniform ion transmission channels via the electrostatic interaction between SO3– groups and Zn2+. While another PEDOT chains can provide electron conducting channels through the conjugated π-π bonds to accelerate charge exchange. Benefiting from the synergistic effect of EIDC polymer layer and SA gel, the as-prepared SA/EIDC gel electrolyte achieves a high ionic conductivity of 41 mS cm–1. The Zn//Zn symmetric batteries exhibit a super-long lifespan of 6750 h at 1 mA cm–2 and 1 mAh cm–2 (>9 months), and cycling life of MnO2-Zn full battery surpasses 4000 cycles. This work presents a new perspective on designing hydrogel electrolytes towards ultra-long lifespan ZIBs.

Reducing Dead Species by Electrochemically‐Densified Cathode‐Interface‐Reaction Layer towards High‐Rate‐Endurable Zn||I‐Br Batteries

Interhalogen‐involved aqueous Zn||halogen batteries (AZHBs) are latent high‐energy systems for grid‐level energy storage, yet usually suffer from poor high‐rate endurability caused by the formation of “dead species”. Herein, via an electrochemically‐densified cathode‐interface‐reaction layer (CIRL), Zn||I‐Br batteries involving interhalogen reactions between the I2 cathode and Br‐ from the electrolytes are initially achieved with excellent high‐rate endurability. Different from that in diluted electrolytes, the CIRL formed in Br‐‐concentrated electrolyte is denser and water‐lean, which enables halogen species conversion with a more rapid charge transfer and lower activation energy. More importantly, the CIRL robustly affords a decent I2 conservation by accelerated conversion kinetics and limited species diffusion, thereby endowing the Zn||I‐Br batteries with an ultralong high‐rate lifespan. The electrochemical mechanism is sufficiently verified by multiple spectral characterizations. Consequently, Zn||I‐Br batteries in Br‐‐concentrated (20 m) electrolytes exhibit an overwhelming rate capability and lifespan to those in Br‐‐diluted (2 m) electrolytes. Typically, when cycled at a large current density of 10 A g‐1, an ultralong lifespan of over 25,000 cycles is achieved with a high retention of 98.3%. This study provides new insight into the CIRL‐dictated active species conservation for high‐rate endurable AZHBs, which could apply to other high‐energy interhalogen batteries.

Reducing Dead Species by Electrochemically-Densified Cathode-Interface-Reaction Layer towards High-Rate-Endurable Zn||I-Br Batteries.

Interhalogen-involved aqueous Zn||halogen batteries (AZHBs) are latent high-energy systems for grid-level energy storage, yet usually suffer from poor high-rate endurability caused by the formation of "dead species". Herein, via an electrochemically-densified cathode-interface-reaction layer (CIRL), Zn||I-Br batteries involving interhalogen reactions between the I2 cathode and Br- from the electrolytes are initially achieved with excellent high-rate endurability. Different from that in diluted electrolytes, the CIRL formed in Br--concentrated electrolyte is denser and water-lean, which enables halogen species conversion with a more rapid charge transfer and lower activation energy. More importantly, the CIRL robustly affords a decent I2 conservation by accelerated conversion kinetics and limited species diffusion, thereby endowing the Zn||I-Br batteries with an ultralong high-rate lifespan. The electrochemical mechanism is sufficiently verified by multiple spectral characterizations. Consequently, Zn||I-Br batteries in Br--concentrated (20 m) electrolytes exhibit an overwhelming rate capability and lifespan to those in Br--diluted (2 m) electrolytes. Typically, when cycled at a large current density of 10 A g-1, an ultralong lifespan of over 25,000 cycles is achieved with a high retention of 98.3%. This study provides new insight into the CIRL-dictated active species conservation for high-rate endurable AZHBs, which could apply to other high-energy interhalogen batteries.

Fabrication of a Stable and Highly Effective Anode Material for Li-Ion/Na-Ion Batteries Utilizing ZIF-12.

Transition metal selenides (TMSs) are receiving considerable interest as improved anode materials for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) due to their considerable theoretical capacity and excellent redox reversibility. Herein, ZIF-12 (zeolitic imidazolate framework) structure is used for the synthesis of Cu2Se/Co3Se4@NPC anode material by pyrolysis of ZIF-12/Se mixture. When Cu2Se/Co3Se4@NPC composite is utilized as an anode electrode material in LIB and SIB half cells, the material demonstrates excellent electrochemical performance and remarkable cycle stability with retaining high capacities. In LIB and SIB half cells, the Cu2Se/Co3Se4@NPC anode material shows the ultralong lifespan at 2000 mAg-1, retaining a capacity of 543 mAhg-1 after 750 cycles, and retaining a capacity of 251 mAhg-1 after 200 cycles at 100 mAg-1, respectively. The porous structure of the Cu2Se/Co3Se4@NPC anode material can not only effectively tolerate the volume expansion of the electrode during discharging and charging, but also facilitate the penetration of electrolyte and efficiently prevents the clustering of active particles. In situ X-ray difraction (XRD) analysis results reveal the high potential of Cu2Se/Co3Se4@NPC composite in building efficient LIBs and SIBs due to reversible conversion reactions of Cu2Se/Co3Se4@NPC for lithium-ion and sodium-ion storage.

Zero-Strain Sodium Nickel Ferrocyanide as Cathode Material for Sodium-Ion Batteries with Ultra-Long Lifespan.

Prussian blue analogues are recognized as one of the most promising cathode materials for sodium-ion batteries (SIBs) owing to the open 3D framework structure with large interstitial sites and developed Na-ion diffusion channels. However, high content of anion vacancy and poor structural stability have hampered the prospect of their application. In this work, sodium nickel ferrocyanide (Na1.34Ni[Fe(CN)6]0.92, NNHCF) is proposed as cathode material for SIBs. N-coordinated Ni-ion can boost NNHCF to possess less Fe[(CN)6]4- defect, low Na-ion migration barrier, and more negative formation energy compared with Na0.91Cu[Fe(CN)6]0.77 (NCHCF), thus exhibiting more active sites, fast electrochemical kinetics behavior and great structure stability. It is confirmed that NNHCF undergoes a solid solution mechanism without phase evolution for reversible Na-ion intercalation/deintercalation, employing Fe associated with C atom as redox center for charge compensation. Therefore, NNHCF contributes a high initial energy density of 180.94 Wh·g-1 at 10 mA·g-1, excellent rate capability, superior cycling stability with ultra-long lifespan of 13000 cycles, and low fading rate of 0.0027% per cycle at 500 mA·g-1. This work sheds light on the construction of low-defect PBA cathodes with outstanding dynamics and stability.

Enhancing the Filler Utilization of Composite Gel Electrolytes via In Situ Solution-Processable Method for Sustainable Sodium-Ion Batteries.

The composite gel electrolyte (CGE), which combines the advantages of inorganic solid-state electrolytes and solid polymer electrolytes, is regarded as the ultimate candidate for constructing batteries with high safety and superior electrode-electrolyte interface contact. However, the ubiquitous agglomeration of nanofillers results in low filler utilization, which seriously reduces structural uniformity and ion transport efficiency, thus restricting the development of consistent and durable batteries. Herein, a solution-processable method to in situ construct CGE with high filler utilization is introduced. The homogeneous metal-organic framework fillers contribute to uniform ionic and electronic filed distribution, realizing a stable electrode-electrolyte interface. Consequently, the CGE with high filler utilization achieves an ultra-long lifespan of 10000 cycles with a capacity retention of 80.2%. This work provides guidance for constructing high-performance CGEs in electrochemical energy-storage devices.

Nanofibrous Covalent Organic Frameworks as the Cathode, Separator, and Anode for Batteries with High Energy Density and Ultrafast-Charging Performance.

To meet the demand for longer driving ranges and shorter charging times of power equipment in electric vehicles, engineering fast-charging batteries with exceptional capacity and extended lifespan is highly desired. In this work, we have developed a stable ultrafast-charging and high-energy-density all-nanofibrous covalent organic framework (COF) battery (ANCB) by designing a series of imine-based nanofibrous COFs for the cathode, separator, and anode by Schiff-base reactions. Hierarchical porous structures enabled by nanofibrous COFs were constructed for enhanced kinetics. Rational chemical structures have been designed for the cathode, separator, and anode materials, respectively. A nanofibrous COF (AA-COF) with bipolarization active sites and a wider layer spacing has been designed using a triphenylamine group for the cathode to achieve high voltage limits with fast mass transport. For the anode, a nanofibrous COF (TT-COF) with abundant polar groups, active sites, and homogenized Li+ flux based on imine, triazine, and benzene has been synthesized to ensure stable fast-charging performance. As for the separator, a COF-based electrospun polyacrylonitrile (PAN) composite nanofibrous separator (BB-COF/PAN) with hierarchical pores and high-temperature stability has been prepared to take up more electrolyte, promote mass transport, and enable as high-temperature operation as possible. The as-assembled ANCB delivers a high energy density of 517 Wh kg-1, a high power density of 9771 W kg-1 with only 56 s of ultrafast-charging time, and high-temperature operational potential, accompanied by a 0.56% capacity fading rate per cycle at 5 A g-1 and 100 °C. This ANCB features an ultralong lifespan and distinguished ultrafast-charging performance, making it a promising candidate for powering equipment in electric vehicles.

An interfacial dual-regulation strategy for ultra-stable 3D Zn metal anodes

The development of Zn metal-batteries, which are viewed as one of the most potential alternatives to lithium ion batteries, is severely hindered by sluggish ion diffusion kinetics and uncontrollable dendritic growth for anodes. Herein, we propose an interfacial dual-regulation strategy for the fabrication of 3D Zn anode through the direct in-situ treatment of benchmark Zn foil. Both rapid ion migration dynamics and homogeneous bottom-up Zn2+ deposition are achieved due to the unique open nanoarray structure with superhydrophilic and zincophilic interface to the electrolyte. Theoretical calculations and finite element simulations reveal this design can effectively redistribute Zn2+ and increase ion flux with a long-lasting 3D diffusion mode, enabling exceptional reversibility during Zn plating/stripping. The as-prepared anode therefore achieves an ultralong lifespan over 3000 h along with high rate capability even at 40 mA cm−2 (depth of discharge ≈ 68.4%). Furthermore, its practical feasibility is validated by a superior capacity retention of 92.5% after 1000 cycles for full cell and high capacity of 112.2 mAh g−1 for pouch cell. This study opens up new opportunities for the development of dendrite-free anodes for aqueous metal batteries.

In Situ Construction of Bimetallic Selenides Heterogeneous Interface on Oxidation-Stable Ti3C2Tx MXene Toward Lithium Storage with Ultrafast Charge Transfer Kinetics.

Ti3C2Tx (MXene) is widely acknowledged as an excellent substrate for constructing heterogeneous structures with transition metal chalcogenides (TMCs) for boosting the electrochemical performance of lithium-ion storage. However, conventional synthesis strategies inevitably lead to poor electrochemical charge transfer due to Ti3C2Tx-derived TiO2 at the heterogeneous interface between Ti3C2Tx and TMCs. Here, an innovative in situ selenization strategy is proposed to replace the originally generated TiO2 on Ti3C2Tx with metallic TiSe2 interphase, clearing the bottleneck of slow charge transfer barrier caused by MXene oxidation. The construction of bimetallic selenide formed by CoSe2 and TiSe2 generates intrinsic electric fields to guide the fast ion diffusion kinetics in a heterogeneous interface. Additionally, the CoSe2/TiSe2/Ti3C2Tx heterogeneous structure with enhanced structural stability and improved rate performance is confirmed by both experiments and theoretical calculations. The engineered heterogeneous structure exhibits an ultra-high pseudocapacitance contribution (73.1% at 0.1mVs-1), rendering it well-suited to offset the kinetics differences between double-layer materials. The assembled lithium-ion capacitor based on CoSe2/TiSe2/Ti3C2Tx possesses a high energy density and an ultralong life span (89.5% after 10000 times at 2Ag-1). This devised strategy provides a feasible solution for utilizing the performance advantages of MXene substrates in lithium storage with ultrafast charge transfer kinetics.

Molecular key tuned steric-hindrance effect toward Zn (100) facet texture anode

Electrolyte additive is one of the most effective strategies to optimize Zn anode in aqueous zinc ion batteries. Few reports are available on the influence of spatial-hindrance effect on Zn2+ deposition behavior. Herein, the environmentally safe aspartame and neotame are selected to finely tune the molecular structure, thereby affecting molecular adsorption behavior as well as Zn2+ diffusion and deposition behavior, and the molecular structure regulation strategy is proposed to achieve the optimization of Zn anode. According to theoretical calculations and experimental conclusions, aspartame, as the molecular robot, uniformly adsorbs on Zn anode surface via oxygen-containing functional groups, captures Zn2+ via −NH2, homogenizes Zn2+ flux, and catalyzes Zn2+ desolvation, resulting in Zn2+ oriented deposition to form Zn (100) facet texture. Benefited from the molecular structure regulation strategy, Zn anode exhibits an ultra-long lifespan of more than 4600 h and an extremely high cumulative plated capacity of 11.7 Ah cm−2. Furthermore, Zn anode operates stably for more than 270 h under 80 % depth of discharge and possesses a high coulombic efficiency of 99.8 % in Zn||Cu half cells. This strategy provides a new perspective on selecting additives.

Ultralong lifespan solid-state sodium battery with a supersodiophilic and fast ionic conductive composite sodium anode

Solid-state sodium batteries (SSNBs) are considered as a promising alternative to organic liquid-based batteries due to their excellent safety, high energy density and cost-effectiveness. However, SSNBs suffer from undesirable interfacial contact between Na and solid-state electrolytes such as NASICON-type Na3Zr2Si2PO12 (NZSP), dendritic growth and dramatic volume changes during cycling, which hinder their development towards actual applications. Herein, dendrite-free composite-type Na/NZSP module with ultrafast built-in ionic conductive framework is designed to promote the Na diffusion kinetics, partially restrict the volume effect, and simultaneously improve the wettability towards NZSP. Thanks to the unique module with supersodiophilic property, the thus-made all-solid-state Na-symmetric cells offer a reduced area specific resistance by more than two orders of magnitudes (from 1774.0 Ω cm2 for the pristine Na/NZSP to 14.1 Ω cm2 for the composite-type Na/NZSP module) and endow an ultralong lifespan of 7800 h at room temperature. Moreover, a full SSNB coupling with the Na/NZSP module and Na3V2(PO4)3 cathode achieves extremely long and stable cycling of more than 5760 cycles at 1.0 C with 87.9 % of capacity retention and high-rate capability at 3.0 C, being among the best achievements reported so far. The findings open a new window of composite-type Na/NZSP module design for high-performance SSNBs.

Engineering Mn Vacancies to Enhance Ion Kinetics in Layered Manganese Silicate for High-Energy and Durable Intercalation Pseudocapacitance.

Transition metal silicates (TMSs) are potential electrodes for aqueous metal-ion intercalation pseudocapacitors owing to their superior theoretical capacity and high structural stability. However, the narrow interlayer spacing and intrinsic inert basal plane of TMSs lead to sluggish ions and charge transfer, causing an undesirable energy storage performance. Herein, rich Mn vacancies are introduced in layered manganous silicates (M2-xS@FA) to expedite K+ diffusion, while enhancing charge storage capacity and prolonging lifespan. In situ characterizations validate the K+ intercalation pseudocapacitance mechanism with evident crystal structure and valence state variations in M2-xS@FA. Both theoretical calculations and electrochemical experimental evaluations elucidate the imperative role of Mn vacancies in enhancing K+ diffusion kinetics and electron transfer through increased interlayer spacing and activated basal plane. Mn vacancies further boost the charge storage capacity by providing additional K+ storage sites, while simultaneously reinforcing local atomic bonding within M2-xS@FA, thereby augmenting structural stability. The assembled aqueous asymmetric solid-state cell, featuring a M2-xS@FA cathode, demonstrates exceptional power and energy densities (144.08 W h kg-1 at 375.80 W kg-1) and ultralong lifespan (100% capacity retention after 10,000 cycles). This work heralds a paradigm whereby modulating cation vacancies in layered TMSs significantly enhances K+ storage and stability for high-energy intercalation pseudocapacitance.

Customizing Pore Structure and Lithiophilic Sites Dual-Gradient Free-Standing 3D Lithium-Based Anode to Enable Excellent Lithium Metal Batteries.

Developing 3D hosts is one of the most promising strategies for putting forward the practical application of lithium(Li)-based anodes. However, the concentration polarization and uniform electric field of the traditional 3D hosts result in undesirable "top growth" of Li, reduced space utilization, and obnoxious dendrites. Herein, a novel dual-gradient 3D host (GDPL-3DH) simultaneously possessing gradient-distributed pore structure and lithiophilic sites is constructed by an electrospinning route. Under the synergistic effect of the gradient-distributed pore and lithiophilic sites, the GDPL-3DH exhibits the gradient-increased electrical conductivity from top to bottom. Also, Li is preferentially and uniformly deposited at the bottom of the GDPL-3DH with a typical "bottom-top" mode confirmed by the optical and SEM images, without Li dendrites. Consequently, an ultra-long lifespan of 5250h of a symmetrical cell at 2mA cm-2 with a fixed capacity of 2 mAh cm-2 is achieved. Also, the full cells based on the LiFePO4, S/C, and LiNi0.8Co0.1Mn0.1O2 cathodes all exhibit excellent performances. Specifically, the LiFePO4-based cell maintains a high capacity of 136.8 mAh g-1 after 700 cycles at 1C (1C = 170mA g-1) with 94.7% capacity retention. The novel dual-gradient strategy broadens the perspective of regulating the mechanism of lithium deposition.

Confining Conversion Chemistry in Intercalation Host for Aqueous Batteries

AbstractConversion‐type anode materials with high theoretical capacities play a pivotal role in developing future aqueous rechargeable batteries (ARBs). However, their sustainable applications have long been impeded by the poor cycling stability and sluggish redox kinetics. Here we show that confining conversion chemistry in intercalation host could overcome the above challenges. Using sodium titanates as a model intercalation host, an integrated layered anode material of iron oxide hydroxide‐pillared titanate (FeNTO) is demonstrated. The conversion reaction is spatially and kinetically confined within sub‐nano interlayer, enabling superlow redox polarization (ca. 4–6 times reduced), ultralong lifespan (up to 8700 cycles) and excellent rate performance. Notably, the charge compensation of interlayer via universal cation intercalation into host endows FeNTO with the capability of operating well in a broad range of aqueous electrolytes (Li+, Na+, K+, Mg2+, Ca2+, etc.). We further demonstrate the large‐scale synthesis of FeNTO thin film and powder, and rational design of quasi‐solid‐state high‐voltage ARB pouch cells powering wearable electronics against extreme mechanical abuse. This work demonstrates a powerful confinement means to access disruptive electrode materials for next‐generation energy devices.

Confining Conversion Chemistry in Intercalation Host for Aqueous Batteries.

Conversion-type anode materials with high theoretical capacities play a pivotal role in developing future aqueous rechargeable batteries (ARBs). However, their sustainable applications have long been impeded by the poor cycling stability and sluggish redox kinetics. Here we show that confining conversion chemistry in intercalation host could overcome the above challenges. Using sodium titanates as a model intercalation host, an integrated layered anode material of iron oxide hydroxide-pillared titanate (FeNTO) is demonstrated. The conversion reaction is spatially and kinetically confined within sub-nano interlayer, enabling superlow redox polarization (ca. 4-6 times reduced), ultralong lifespan (up to 8700 cycles) and excellent rate performance. Notably, the charge compensation of interlayer via universal cation intercalation into host endows FeNTO with the capability of operating well in a broad range of aqueous electrolytes (Li+, Na+, K+, Mg2+, Ca2+, etc.). We further demonstrate the large-scale synthesis of FeNTO thin film and powder, and rational design of quasi-solid-state high-voltage ARB pouch cells powering wearable electronics against extreme mechanical abuse. This work demonstrates a powerful confinement means to access disruptive electrode materials for next-generation energy devices.

Boosting ORR/OER bifunctional electrocatalysis by promoting electronic redistribution of Fe-N-C on CoFe-FeNC for ultra-long rechargeable Zn-air batteries

Fe-N-C materials are among the most promising platinum group metals-free catalysts for air cathode of Zn-air batteries (ZABs). However, they are still limited by sluggish reaction kinetics. Herein, we synthesize a novel and effective mesoporous carbon embedded with CoFe nanoclusters, coated with graphitic carbon layers (denoted as CoFe-FeNC). CoFe-FeNC is derived from the pyrolysis of metal-organic complex precursors with grafted iron porphyrin. The CoFe-FeNC catalyst exhibits a half-wave potential (E1/2) of 0.876 V for the oxygen reduction reaction (ORR) and a potential of 1.526 V at 10 mA cm−2 (Ej=10) for the oxygen evolution reaction (OER) in alkaline solutions. Theoretical calculations reveal that the presence of CoFe clusters regulates the electronic structure, optimizing adsorption and desorption during the catalytic reaction. Moreover, flow-ZABs utilizing CoFe-FeNC as the cathode material demonstrate a high specific capacity of 767.5 mAh gZn−1 and an ultra-long lifespan exceeding 1200 h. Additionally, flexible quasi-solid-state rechargeable ZABs incorporating CoFe-FeNC electrocatalysts as the cathode demonstrate well cycling and mechanical flexibility.

The Ni Heteroatom‐Induced Electronic Structure Tailoring of Ultrastable Fe3N@NCPs Nanosheets Electrocatalyst for Boosting Alkaline Seawater Electrolysis

AbstractThe exploration of high‐efficiency electrocatalysts is becoming indispensable for the production of H2 from electrochemcial seawater splitting. Herein, a feasible strategy is developed to realize the in situ encapsulation of Ni‐decorated Fe3N into porous N‐doped carbon nanolayer, abbreviated as Nix‐Fe3N@NCPs, by an association of wet‐impregnation treatment and thermal annealing. More concretely, the doping of Ni can initiate the synergistic effect to optimize the internal electronic structure, which strengthen the adsorption of intermediates and interface charge transfer. Meantime, the architecture of NCPs encapsulation nanolayer not only enhances the conductivity and the structural stability, but also effectively prevents Cl− ions transport from poisoning of electrocatalytic active sites. On these grounds, the preferred Ni0.10‐Fe3N@NCPs electrocatalyst delivers the exceptional bifunctional electrocatalytic performance in electrolytic seawater. The corresponding HER and OER overpotentials to attain the current densities of 10, 100, and 500 mA cm−2 are only required 47, 147, and 291 mV as well as 152, 249, and 312 mV, respectively. In addition, the Ni0.10‐Fe3N@NCPs electrocatalysts achieves an ultra‐low voltage of 1.80 V at 500 mA cm−2 with ultralong lifespan of 1200 h in zero‐gap alkaline electrolyzer. This work provides a cutting‐edge scientific research exploration for the development of electrocatalyst for seawater electrolysis.