N-doped Porous Carbon Materials Research Articles

Preparation of N-doped carbon-modified Na3V2(PO4)2F3 based on ZIF-8 as a template and its electrochemical properties

N-doped porous carbon material (N-PC) was generated through high-temperature cracking, using ZIF-8 as a template, and preparation of Na3V2(PO4)2F3/N-PC composites were designed and prepared as cathode materials for sodium-ion batteries, and the electrochemical sodium storage performance was systematically investigated. The physical characterization results showed that the addition of N-PC played a role in increasing the electrical conductivity of Na3V2(PO4)2F3 material and improving the specific surface area. The electrochemical test results showed that the discharge specific capacity of Na3V2(PO4)2F3/N-PC composite was 109.56 mAh/g at 0.1C, and the capacity retention rate was 85.10 % after 100 cycles, and the RSEI of Na3V2(PO4)2F3/N-PC composite (81.55 Ω) is better than that of Na3V2(PO4)2F3 pure-phase material (142.5 Ω), which indicates that the ion transfer impedance of the modified material has been effectively reduced, and the ion de-embedding is more fluent.

Preparation of porous carbon electrode materials from potassium hydroxide extract of lignite doped with nitrogen

Lignite is cheap, easy to obtain and rich in pores, so it was used as an electrode material for supercapacitors early. In this paper, Yimin lignite (YM) was used as raw material, and KOH was used to extract organic components. Melamine was adulterated into the extracted material for thorough mixing. The reaction mechanism and structural changes in it were explored. Experimental results and density functional theory (DFT) calculations showed that introducing nitrogen atoms into the coal-based activated carbon leads to a rearrangement of the carbon skeleton structure and changes the surface chemical environment. In this process, we adjust the porosity, specific surface area and discharge specific capacity of the produced carbon materials by changing nitrogen doping ratio, activation time and activation temperature. The excellent N-doped porous carbon material At-120 (activation time:120 min) was prepared with a high specific surface area (SBET: 3020 m2/g), abundant micropores (Vmic: 1.242 cm3/g), proper mesopores (Vmes: 0.182 cm3/g, Vmes ratio: 12.6 %), low impurity content, and high amount of N doping (6.43 wt%). These characteristics of At-120 enabled it to have a high specific capacitance value of 433.5 F/g at a current density of 1 A/g. The enhanced At-120 has 42.18 % higher specific capacitance than the undoped lignite alkali extract(LC).

Zinc sulfide quantum dots modified 3D Nitrogen-Doped framework carbon enhances the ion transport rate of potassium ion hybrid capacitors

The potassium-ion hybrid capacitor (PIHC) has garnered considerable attention due to its ability to leverage the advantages of both battery-type anodes and capacitor-type cathodes simultaneously. Nevertheless, the slow K+ transfer rate between the PIHC battery-type anode and capacitor-type cathode significantly impedes the overall performance. Herein, we have employed quantum-sized zinc sulfide (ZnS) immobilized within a three-dimensional N-doped porous carbon framework (ZnSQDS@3DNC) as a standalone anode. The corresponding three-dimensional N-doped porous carbon (3DNC) serves as the cathode, thereby constructing a PIHC device. The strong coupling between ZnS quantum dots and N-doped three-dimensional porous carbon material effectively enhances ion/electron transport, facilitating intercalation-conversion-exfoliation reactions and improving K+ transfer rates. The numerous active sites within the 3DNC significantly enhance the capacitance performance of the cathode, facilitating the reversible adsorption and desorption of FSI-. The values of DK+ have all been calculated to be within the range of 10-10 to 10-9 cm2 s−1, indicating the rapid diffusion capability of this ZnSQDs@3DNC structure. More impressively, the assembled PIHC device can achieve high energy densities of 179.9 Wh kg−1 at power densities of 200 W kg−1, with an ultralong cycling life over 10,000 cycles. This study serves to advance the development of metal-ion hybrid capacitors and provides direction for improving ion transport kinetics.

New Highly Graphitized N-Doped Carbon as a Robust Support for Pt Electrocatalysts

For polymer electrolyte membrane fuel cells (PEMFCs), the state-of-the-art electrocatalysts are based on Pt group metals deposited over electroconductive porous carbon support. However, current carbon supports suffer from carbon corrosion during repeated start-stop operations, causing performance degradation. We report a new strategy to produce highly graphitized porous carbon with controllable N-doping that uses low-temperature synthesis (650 ℃) from g-C3N4 carbon-nitrogen precursor with pyrolysis using Mg. The high graphiticity is confirmed by high-intensity 2D Raman peak with low ID/IG (0.57), pronounced graphitic XRD planes, and excellent conductivity. Without further post-treatment, this highly graphitized N-doped porous carbon (GNPC) material combines high pyrrolic-N content with high porosity. Supporting Pt on GNPC exhibits excellent oxygen reduction activity for PEMFC with greatly improved durability as proved by real-time loss measurements of Pt and carbon, the first to surpass the DOE 2025 durability targets for both catalyst and support. The Pt/GNPC prepared at 650 oC shows 32 and 24% drop in mass activity after accelerated durability tests of both electrocatalyst and support, respectively, which are less than DOE target of 40% loss. The atomistic basis for this durability is explained via quantum mechanics-based molecular dynamics simulations. Interestingly, it is found that pyrrolic-N strongly interacts with Pt, making the Pt catalyst more stable during fuel cell reaction. We expect that high porosity robust graphitized materials will lead to many other novel applications for electrocatalysis with durable carbon frameworks.

N-doped defect-rich porous carbon nanosheets framework from renewable biomass as efficient metal-free bifunctional electrocatalysts for HER and OER application

In response to the demand for clean, renewable energy sources and storage technologies, innovative materials and combinations have been developed at reasonable prices as effective electrode materials. Current research and development of carbon-based metal-free catalysts have opened up new research areas for bifunctional electrocatalysts for overall water splitting. Herein, we developed N-self-doped defect-rich porous carbon nanosheets derived from platycladus orientalis tree-cone biomass for overall water splitting. The developed N-self-doped defect-rich porous carbon nanosheets have large surface areas (3369 m2/g), high pore volumes (2.1 cm3 g−1), and high electrical conductivities (12.69 S/cm). N-self-doped defect-rich porous carbon nanosheet framework was employed in water splitting as a dual function in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Electrodes fabricated from the KOH-II ABC nanosheets show excellent OER and HER performances in the 0.5 M H2SO4 solution. The current density of 10 mA cm−2 is reached at a low overpotential of 90 mV for OER and 188 mV for HER. In addition, KOH-II ABC nanosheets also show a remarkable performance on overall water splitting, which only required a cell voltage of 1.49 V to reach current densities of 10 mA cm−2 in 0.5 M H2SO4 solution. The presence of defects in the carbon nanosheets, higher specific surface area, excellent electrochemical active surface area and N doping effectively enhance the reaction kinetics for attaining efficient OER and HER performances. This facile approach to preparing biomass-derived N-doped defect-rich porous carbon materials empowers next-generation green fuel conversion technologies for carbon neutrality.

FeNi alloys encapsulated with N-doped porous carbon nanotubes as highly efficient and durable CO2 reduction electrocatalyst

The development of highly efficient, cost-effective, and robustly stable electrocatalysts for CO2 reduction remains a significant challenge. In this study, a promising CO2 reduction electrocatalyst composed of nanostructured transition metal alloys (i.e., FeNi, FeCo, or CoNi) nanoparticles encapsulated on N-doped porous carbon material is reported. Among the different compositions, FeNi@N-CNTs-1100 exhibited the most efficient CO2ER activity and exceptional stability. It demonstrated a high CO Faradaic efficiency of over 90 % in a wide potential range (–0.47 to –0.97 V (vs. RHE)), with a CO partial current density of 20.18 mA cm−2 at –0.97 V (vs. RHE). Notably, it achieved a long-term stability of 35 h at –0.77 V (vs. RHE) in an H-cell with 0.5 M KHCO3 electrolyte. Various characterization techniques and designed experiments revealed that FeNi@N-CNTs-1100 exhibited enhanced intrinsic catalytic activity and CO selectivity due to optimized *COOH adsorption and *CO desorption compared to the other catalysts studied.

Regulating N-doping strategies to construct 3D interconnected abundant porous N-doped carbon for polarization loss-enhanced microwave absorbers: Theory, design, and experiments

The widespread proliferation of modern portable electronic devices has necessitated the development of functional materials with high-efficiency microwave absorption properties. In this study, we utilized biomass-derived jujube shells as a carbon source and employed a nitrogen-doping process to modify carbon materials, resulting in the fabrication of outstanding microwave-absorbing biomass-based nitrogen-doped porous carbon. Additionally, we discussed the influence of different nitrogen sources on material structure and microwave absorption performance. These N-doped porous carbon materials exhibited excellent specific surface areas, particularly Org-N, which facilitated the formation of conductive networks and the multi-stage reflection and scattering of microwave. Moreover, N-doping created numerous defect sites and heterogeneous structures, improving impedance matching, thus promoting dipole polarization and interface polarization effects, which accelerated electron migration and interlayer hopping, contributing to the attenuation of microwave energy. The lowest reflection loss for Org-N, Inorg-N, and Mixed-N reached −27.3 dB, −40.9 dB, and −45.6 dB, respectively. Mixed-N exhibited optimal microwave absorption performance at 9.9 GHz with d = 2.4 mm and achieved an effective absorption bandwidth (EAB10) of 3.0 GHz (11.0 GHz–14.0 GHz) at d = 2.0 mm. Additionally, the enhancement of polarization relaxation effects was elucidated by examining the charge density distribution in molecular models featuring various N-doping forms. Consequently, biomass-derived N-doped porous carbon materials emerge as lightweight and highly efficient functional materials for microwave absorption purposes.

Enhanced adsorption of organic pollutants using N-doped porous carbon derived from hemp stems: Insights into the mechanism

Nitrogen (N) doping is commonly used to modify biochar and enhance its adsorption performance. However, the significance of pyrrolic-N in pollutant adsorption is frequently overlooked. In this study, N-doped porous carbon materials (NBC) have been synthesized using hemp stems as the carbon source through pyrolysis in one step for the efficient removal of organic pollutants. The incorporation of the pyrrolic-N functional group in NBC leads to an increase in surface defects, electronegativity, and electron conductivity. As a result, the Qmax of tetracycline (TC) reaches 577.60 mg/g, which is twice as much as activated carbon with a similar specific surface area. The characterization and theoretical calculation demonstrate that the NBC adsorbent adsorbs TC primarily through cation-π and π-π interactions facilitated by pyrrolic-N, as well as weak electrostatic interactions induced by –COOH. In actual landfill leachate adsorption experiments, the NBC effectively reduced chemical oxygen demand and ammonia–nitrogen levels in wastewater. Additionally, the growth of sprouts planted on contaminated soil treated with NBC (sulfamethoxazole, 50 mg/kg) is restored to levels observed on uncontaminated soil, thus demonstrating its practicality.

N-doped porous carbon material derived by MOFs calcined in proper oxygen atmosphere as high-performance catalyst for the low-temperature NH3-SCR

Nowadays, with the development of industrial applicability and low energy consumption, a catalyst for implementing the NH3-SCR reaction at low temperature is urgently needed. MOFs derivatives (MD) prepared by calcined of MOFs could reserve many characteristics of MOFs show great potential. And in order to prepare high NO conversion catalysts, the pyrolysis conditions of MOFs draw more attentions in the preparation process. Therefore, in this work, after calcined MOFs precursor at the atmosphere of different oxygen concentration (pure oxygen, air, nitrogen), a series of nanocomposite are obtained. The experimental results reveal that catalyst calcined in the atmosphere of proper oxygen concentration (air) has the best deNOx performance and better resistance of water and sulfur dioxide. Further explorations exhibit that it could be primarily ascribed to the distinctive porous structure which is made up of well-dispersed MnOx-CeOx together with N-doped carbon skeleton. The conductivity can be efficiently increased to hasten the transfer of electrons. In addition, in situ DRIFTS results indicate that the interaction on the surface of catalyst calcined in air is stronger and the mechanism of prepared catalysts is Eley-Rideal (E-R) at low temperature and Langmuir-Hinshelwood (L-H) at high temperature.

In Situ Preparation of Polyamine-Derived Ru Cluster@N-Doped Porous Carbon Nanoplates for Hydrogen Evolution over Wide pH Ranges.

Efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) are required for producing hydrogen energy through water splitting. Carbon materials as HER catalyst supports are explored widely since the strong metal-support interactions are generally believed to be active and stable toward HER. Herein, we report N-doped porous carbon materials as novel substrates to stabilize the cluster metal sites through the Ru(III) polyamine complexes, which play an important role not only in efficient electron transfer but also in the increasing utilization of metallic active sites. Meanwhile, due to the strong metal-support interactions driven by Ru(III) polyamine complexes, the obtained Ru cluster with a mass loading of 3% on N-doped porous carbon nanoplates (Ru cluster@NCs) exhibits robust stability for HER at a constant voltage, proving to be a promising candidate catalyst for HER. Density functional theory calculations further indicate that the Gibbs free energy (ΔG) of adsorbed H* of Ru cluster@NCs is much closer to zero compared to Ru@(10%)NCs and Pt/C(20%), thus Ru cluster@NCs facilitate the HER process.

3D Nitrogen-Doped Porous Carbon Supported Pt Catalyst for Electrocatalytic Oxidation of Glucose

Glucose fuel cells have attracted widespread attention in the biomedical field due to their ability to generate electrical energy continuously. The development of this technology has great potential in the application of powering implantable medical devices. However, the efficiency of the glucose oxidation reaction at the anode of the fuel cell is low, and a catalyst needs to be added to improve the reaction efficiency. Platinum (Pt) catalysts are prone to agglomerate during use, which limits the improvement of their properties such as catalytic activity and stability. To address this problem, in this paper, a three-dimensional ( 3D) N-doped porous carbon (NCZIF-8) material with a large specific surface area was prepared as a catalyst carrier using ZIF-8 as a precursor. Low loading rate of platinum (10 wt. %) was prepared (10% Pt/NCZIF-8) and used as catalysts for glucose oxidation reaction. The materials were structurally characterized by XRD, SEM, TEM, Raman and FT-IR, etc. The electrocatalytic properties of the materials were characterized using an electrochemical workstation. It was shown that the incorporation of NCZIF-8 carrier promotes the dispersion of Pt nanoparticles (NPs) and the utilization of the catalyst, which enhances the catalytic activity and stability of catalysts during electrocatalytic glucose oxidation. After 300 times cyclic voltammetry (CV) tests, the peak current density of 10% Pt/NCZIF-8 only decreased by 21. 12% and 8. 59% in the double-layer region and oxygen region, respectively, indicating the excellent stability of the catalyst. This kind of catalyst with low loading rate of precious metal has great potential for its practical application by improving catalyst utilization, which not only improves the catalytic efficiency but also reduces the material cost.

Phosphate-decorated Fe-N-C to promote electrocatalytic oxygen reaction activities for highly stable zinc-air batteries

An obvious challenge for rechargeable Zn-air batteries (ZABs) is the impact of large charge potentials on the oxidation of their cathode catalysts, which accelerates the corrosion of the carbon electrodes, and significantly compromises their stability. It is therefore necessary to design simple methods aimed at facilitating the oxygen evolution reaction (OER) processes of ZABs to suppress the corrosion of their cathode materials. Herein, a biomass-derived N-doped porous carbon material coupled with Fe3O4 and Fe2N nanoparticles and modified with phosphorus (P-Fe3O4/Fe2N@NPC) was designed as an air-cathode to reduce the charging voltage of ZABs. It exhibited excellent ORR/OER bifunctional electrocatalytic activities, and the assembled ZAB displayed an ultra-long service life. DFT calculations showed that the P-modification modulated the electronic state and coordination environment of the active iron atom, thereby significantly enhancing the OER activity of P-Fe3O4/Fe2N@NPC.

N-doped porous carbon-anchored zinc single-atom as an efficient and robust heterogeneous catalyst for glycerol carbonylation with urea

Constructing highly efficient and stable heterogeneous catalysts for glycerol carbonylation is a very significant subject for its importance in promoting the development of biodiesel industry. Herein, a carbon-based single-Zn-atom catalyst (Zn1/NC) was prepared by using N-doped porous carbon material (NC) as support via a wet impregnation technique, following a thermal treatment at 600 °C. Various characterization results demonstrate that Zn2+ cations are atomically dispersed on the surface of NC support by coordination with the existed N- and O-containing groups. The Zn1/NC catalyst exhibited outstanding catalytic activity, selectivity and stability for glycerol carbonylation with urea at mild conditions. Operando ReactIR spectra results show that urea molecules could be easily activated by the single-atom Zn catalyst then react with glycerol molecules to generate the main product of glycerol carbonate via an intermediate of 2,3-dihydroxypropyl carbamate. Density functional theory calculations reveal that NC support could provide a unique coordination environments for the single-atom site of Zn2+, which can guarantee the preferential adsorption of urea molecule (rather than glycerol) and effectively inhibit the generation of the unfavorable Zn-glycerol complex, thus leading to the formation of highly efficient and robust heterogeneous catalyst for glycerol carbonylation with urea.

N-doped highly microporous carbon derived from the self-assembled lignin/chitosan composites beads for selective CO2 capture and efficient p-nitrophenol adsorption

Green and low-cost biomass-based porous carbon adsorbents have a good prospect for the removal of some environmental pollutants. Here, sodium lignosulphonate, chitosan, and activator were firstly combined into wet gel microbeads through in situ self-assembly method, and then derived the novel porous carbon adsorption materials (LC-Cs) by freeze-drying and one-step activation carbonization. The results showed that LC-Cs had large specific surface areas (892.4∼1307.8 m2/g), high microporosity (87.4∼89.2%), and rich nitrogen content (3.01∼4.92%), and these structural parameters showed good linear dependence with the dosage ratio of lignin to chitosan. Next, LC-Cs carbon showed efficient CO2 capture (173.9–215.2 mg/g) and high CO2/N2 selectivity (up to IAST:145.9, Henry’s law: 23.5), specially, the relationships between the CO2 capture and the structural parameters were investigated in detail, and also performed DFT calculation. In addition, LC-C22 had the maximum adsorption capacity of p-nitrophenol (PNP) as 592.8 mg/g, and the adsorption isotherms and kinetic study indicated that they belonged to the multilayer adsorption on the heterogeneous surfaces, and the chemical adsorption played the dominated roles, and then further studied the adsorption mechanism by characterization techniques. This work provided a green and facile strategy for preparing structurally controllable N-doped porous carbon materials, as well as offered good potential adsorbents for PNP removal and CO2 capture.

Cobalt Nanoparticles Anchored on N-Doped Porous Carbon Derived from Yeast for Enhanced Electrocatalytic Oxygen Reduction Reaction.

Biomass-derived carbon materials have received extensive attention for use in high-performance electrocatalysts. In this study, a highly efficient electrocatalyst is developed with Co nanoparticles anchored on N-doped porous carbon material (CoNC) by using yeast as a biomass precursor through a facial activation and pyrolysis process. CoNC exhibits comparable catalytic activity with commercial 20 % Pt/C for the oxygen reduction reaction (ORR) with a half-wave potential of 0.854 V. A home-made primary Zn-air battery exhibited an open circuit potential of 1.45 V and a peak power density of 188 mW cm-2 . Moreover, the discharge voltage of the primary battery maintained at a stable value up to 9 days. The enhanced performance of CoNC was probably ascribed to its high content of pyridinic-N and graphitic-N species, extra Co loading and porous structure, which provided sufficient active sites and channels to promote mass/electron transfer for ORR. This work provides a promising strategy to develop an efficient non-noble metal carbon-based electrocatalyst for fuel cells and metal-air batteries.

Preparation of nitrogen-doped hierarchical porous carbon aerogels from agricultural wastes for efficient pollution adsorption

The development of green, economic and high-performance pollutant adsorption materials is an important way to meet severe environmental challenges. Herein, aerogel-like N-doped hierarchical porous carbon materials (NHCs) were prepared by rapid pyrolysis of corn straw and urea using KHCO3 as the activator. A series of characterizations including SEM, (HR)TEM, N2 absorption and desorption, FTIR, Raman, XPS, and elemental analysis were carried out to explore influences of activation temperature on the physicochemical properties of NHCs. It is found that NHC-800 prepared at 800 °C has a well-developed hierarchical pore structure, a high specific surface area (1871 m2/g) and a very low density (0.032 g/cm3). Influences of various parameters including activation temperature, urea and KHCO3 ratio, biomass type on the NHC adsorption performance were investigated. The material naming NHC-800 prepared from corn straw (corn straw: KHCO3: urea is 1:4:1) has the best methylene blue adsorption performance, with a maximum adsorption capacity of 1009.6 mg/g. Adsorption kinetics and thermodynamic analysis were carried out, and mechanism research was performed. It is found that urea not only provides pyridinic N chemisorbent sites, but also provides more activable sites for NHCs to generate more pore structures for physical adsorption. Performances on the adsorption of acid fuchsin, methyl orange, tetracycline, Cr6+, Cu2+ and actual wastewater were also studied, and it is found that NHC-800 can selectively and effectively remove organic pollutants while retaining metal ions.

ORR Catalysts Derived from Biopolymers

Due to the limited reaction rate of the oxygen reduction reaction (ORR), it is considered as a limiting factor in the performance of fuel cells and metal-air batteries. Platinum is considered the benchmark catalyst for ORR; however, the scarcity of platinum, its high price, the drift phenomenon, its insufficient durability, and its susceptibility to gas poisoning are the reasons for the constant search for new ORR catalysts. Carbon-based catalysts show exceptional promise in this respect considering economic profitability and activity, and, in addition, they have favorable conductivity and often a large specific surface area. The use of chitin, cellulose, lignin, coconut shell particles, shrimp shells, and even hair for this purpose was reported, as they had similar electrochemical activity regarding Pt. Alginate, a natural polymer and a constituent of brown algae, can be successfully used to obtain carbon materials that catalyze ORR. In addition, metal atomic-level catalysts and metal N-doped porous carbon materials, obtained from sodium alginate as a precursor, have been proposed as efficient electrocatalysts for ORR. Except for alginate, other biopolymers have been reported to play an important role in the preparation of ORR catalysts. In this review, recent advances regarding biopolymer-derived ORR catalysts are summarized, with a focus on alginate as a source.

Nitrogen Self-Doping Carbon Derived from Functionalized Poly(Vinylidene Fluoride) (PVDF) for Supercapacitor and Adsorption Application.

A new synthetic strategy has been developed for the facile fabrication of a N-doped porous carbon (NC-800) material via a facile carbonization of functionalized poly(vinylidene fluoride) (PVDF). The prepared NC-800 exhibits good specific capacitance of 205 F/g at 1 A/g and cycle stability (95.2% retention after 5000 cycles at 1 A/g). The adsorption capacity of NC-800 on methylene blue and methyl orange was 780 mg/g and 800 mg/g, respectively. The facile and economical method and good performance (supercapacitor and adsorption) suggest that the NC-800 is a promising material for energy storage and adsorption.

Nano-architecture of MOF (ZIF-67)-based Co3O4 NPs@N-doped porous carbon polyhedral nanocomposites for oxidative degradation of antibiotic sulfamethoxazole from wastewater

Co3O4 NPs in N-doped porous carbon (Co3O4 NPs@N-PC) materials were prepared by one-pot pyrolysis of a ZIF-67 powder under N2 atmosphere and followed by oxidation under air atmosphere (200 °C) toward promotion catalytic activity and activation of peroxymonosulfate (PMS) to degradation sulfamethoxazole (SMZ). 2-methylimidazole was used as a nitrogen source and a competitive ligand for the synthesis of Co3O4 NPs@N-PC, which in addition to affecting nucleation and growth of the crystal, promotes the production of active Co–N sites. Co3O4 NPs@N-PC nano-architecture has high specific surface areas (250 m2 g−1) and is a non-toxic, effective and stable PMS activator. The effect of operating parameters including SMZ concentration, catalyst dosage, temperature and pH in the presence of Co3O4 NPs@N-PC was investigated. The Co3O4 NPs@N-PC composite showed superior performance in activating PMS over a wide range of pH (2–10) and different temperatures so that complete degradation of SMZ (50 μM, 100 mL) was achieved within 15 min. The role of Co2+/Co3+ redox system in the mechanism before and after PMS activation was determined using XPS analysis. Surface-generated radicals led to the degradation of SMZ, in which the SMZ degradation rate attained 0.21 min−1 with the mineralization of 36.8%. The feasible degradation mechanism of SMZ was studied in the presence of different scavengers and it was revealed that the degradation reaction proceeds from the radical/non-radical pathway and in this process most of the SO4− and OH radicals are dominant. The recoverability and reuse of Co3O4 NPs@N-PC were evaluated to confirm its stability and potential for SMZ degradation and it was observed that the catalyst maintains its catalytic power for at least 5 cycles.

Anchoring high-mass iodine to nanoporous carbon with large-volume micropores and rich pyridine-N sites for high-energy-density and long-life Zn-I2 aqueous battery

Aqueous Zn-I2 batteries (AZIBs) are highly desirable for green energy-storage technologies, but their development was greatly limited by their unsatisfactory energy densities. Herein, we report high-energy-density rechargeable AZIBs achieved by anchoring high-mass iodine to a distinctive N-doped hierarchical porous carbon (NHPC) material with large micropore volume and rich N-doping. The NHPC combined strong iodine confinement caused by the micropore and powerful chemisorption of iodine species with pyridine-N doping, which enabled high loads of iodine up to 61.6 wt%. Notably, density functional theory calculations and experimental studies showed that abundant pyridine-N active sites promoted electron transfer, and the interconnected micro-mesoporous structure facilitated the Zn-ion diffusion to synergistically promote the redox kinetics of AZIBs. The high content of iodine-loading cathode exhibited a high capacity of 219.3 mA h g−1 at 1.0 C, indicating excellent rate capability and superior cycling stability with a low capacity decay of 0.00147% per cycle within 10,000 cycles at 5.0 C. In addition, a preliminary device assembled with three batteries in series provided a high energy density of up to 72.6 W h kg−1 calculated by the total mass of the battery, which is almost two times that of the commercial aqueous lead-acid and Ni-Cd batteries. The high energy density and long cycle life of this aqueous battery indicate its great application potential in large-scale energy storage.