High-performance Energy Storage Materials Research Articles

Electrochemical evaluation of low crystalline CoFe2O4@Reduced graphene oxide nanocomposite for hybrid supercapacitor application

The development of high-performance and cost-effective energy storage materials remains of significant scientific interest. Here, low-crystalline (LC) binary transition metal oxide (BTMO) CoFe2O4 is studied for its application in a hybrid supercapacitor. This disordered LC CoFe2O4 material was prepared by the co-precipitation method, and to improve the electron transport property of the LC CoFe2O4, a composite was prepared with reduced graphene oxide (RGO). LC CoFe2O4@rGO interconnected network enhances the electrolyte ion diffusion within the material. This CoFe2O4@RGO shows an electrochemical performance of 2247.82 mF cm−2 at a current density of 1 mA cm−2. The cyclic stability study is performed to CF@RGO 20 % electrode for 2000 cycles at 30 mA cm−2 current density. Further, to understand the charge storage mechanism, Dunn analysis is done, the capacitive and diffusion contributions to charge storage are studied. Besides, the charge transfer and diffusion characteristics of the material were studied using electrochemical impedance spectroscopy. So, these LC CoFe2O4@RGO based materials with improved ion diffusivity and flexibility in synthesis make them attractive candidates for the development of high-performance and cost-effective supercapacitor.

High energy storage properties for dielectric composite by asymmetric three-layer films design

Polymer dielectrics are extensively studied for applications in electronics pulsed power systems owing to their excellent processability, high breakdown strength and low energy loss. To synergistically achieve high energy density and high discharge efficiency, we report an asymmetric three-layer all-polymer composite, which consists of a mixture of P(VDF-HFP) and P(St-MMA) as an intermediate layer sandwiched between a linear polymer P(St-MMA) dielectric layer and a nonlinear polymer P(VDF-HFP) dielectric layer. The results of the study showed that a high efficiency of 94.14 % and a high energy discharge density of 14.86 J/cm3 were achieved concurrently. In this case, the linear dielectric layer provides high energy efficiency, and the high energy density is provided by the nonlinear layer dielectric layer. In particular, the middle layer can effectively balance the electric field distribution, which improves the breakdown strength and increases the energy density. The structural design of asymmetric three-layer all-polymer films provides an effective way to realize high-performance dielectric energy storage materials.

In-situ-assembled polyaniline frameworks on reduced graphene oxide toward high-performance energy-storage materials

PANI exhibited considerable potential in the conversion and storage of energy systems because of its high elasticity, large specific capacitance, multiple oxidation states, and relatively inexpensive. Unfortunately, PANI's poor stability restricts its usage. The coupling of PANI and other active materials has the potential to overcome PANI's inherent limitations. Here, we successfully synthesized reduced graphene oxide (rGO) that was utilized as a carbon substrate for in situ chemical polymerization of PANI at different operating temperatures [0°C, room temperature (RT), and 50°C]. The fabricated PANI-RT/rGO nanocomposite showed a high porosity with a high surface area, acting as an ions diffusion pathway. The estimated electrochemical results of the prepared electrodes, PANI-RT, PANI-50, PANI-0, and PANI-RT/rGO electrodes at an applied current of 2 A.g−1 are 832 F.g−1 (418 C/g), 256 F.g−1 (128 C/g), and 224 F.g−1 (112 C/g), and 1056 F.g−1 (528 C/g), respectively. The capacitance of the PANI-RT/rGO electrode is much larger than that of the others, and rGO incorporation demonstrates a key factor in improving the electrochemical storage capability. Furthermore, the device is stable, keeping 90 % of its original capacity following 3 K charge/discharge repeated runs at 5 A g−1.

A novel anode with improved electrochemical performance based on cobalt squarate for lithium-ion batteries

Organics matter squaric acid with small molecules and multiple active sites are of great potential to obtain a high theoretical specific capacity. However, square acids are easily dissolved in the electrolyte, causing it to exhibit characteristics of low capacity and poor cycling performance. Metal ions are introduced to create metal–organic frameworks (MOFs), which is one of the efficient solutions for the aforementioned problems. MOFs based on π-d systems can improve stabilities and inhibit the dissolution of organic ligands. Meanwhile, different metal ions can modify its electrochemical properties, especially those with redox activity, which can significantly improve the capacity and stability of the MOFs. In this paper, the M−SQ (M = Co, Ni, Mn) based on square acid was synthesized, compare to Ni-SQ and Mn-SQ, Co-SQ with multiple redox-active centers shown greater reversible capacity and cycle stability, which has 1242.2 mA h g−1 at 0.1 A g−1, it is present an excellent capacity, and Co-SQ also has good rate capacity, when current density added to 2 A g−1, it has 807.9 mA h g−1. Meanwhile, Co-SQ showing an outstanding long cycle life with 481.8 mA h g−1 after 700 cycles at 1 A g−1. In addition, Co-SQ with a porous structure has a higher capacity than Co-SQ-NaOH with rod-like structure. Further, the Li+ storage advantage of the porous structure Co-SQ was revealed by kinetic studies. The strategy though tunable active sites of metals and carbonyl is great potential for obtaining high-performance energy storage materials.

Bimetal-organic frameworks derived redox-type composite materials for high-performance energy storage

Electrodes and electroactive materials are crucial components in the development of supercapacitors due to their geometric properties. In this study, bimetal-organic frameworks (Bi-MOFs, ZIF-8@ZIF-67) were utilized as electrode materials for a high-performance hybrid supercapacitor (HSC) by designing a novel synthesis of metallic carbonate hydroxide/oxides. In particular, the Bi-MOFs function as a sacrificial precursor in the synthesis of hollow NiMn(CO3)0.5·0·.11H2O/ZnO@Co3O4 CNCs (NM-CH/ZnO@Co3O4 CNCs) cubic composite materials by a straightforward low-temperature treatment. The NM-CH/ZnO@Co3O4 CNCs exhibited exceptional electrochemical performance with high specific capacity of 196.3 ± 0.08 mAh/g, specific capacitance of 1179 ± 0.10 F g−1 at 0.5 A g−1, and outstanding cycling stability of 98% after 25,000 cycles compared to the other electrode materials. The porous and hollow structure, along with a large surface area, contributed to the enhanced electrochemical properties of the composite material. An HSC was constructed using NM-CH/ZnO@Co3O4 CNCs as the cathode and activated porous carbon (APC) as the anode, resulting in a device with a specific energy of 33 ± 0.12 Wh kg−1 and a power density of 19354 ± 0.07 W kg−1. The use of Bi-MOF electrodes presents new avenues for the development of high-performance energy storage materials, with the potential for industrial energy storage application demonstrated though the successful powering of portable lightbulbs.

Constructing a 3D Ion Transport Channel-Based CNF Composite Film with an Intercalated Structure for Superior Performance Flexible Supercapacitors.

The weak stiffness, huge thickness, and low specific capacitance of commonly utilized flexible supercapacitors hinder their great electrochemical performance. Learning from a biomimetic interface strategy, we design flexible film electrodes based on functional intercalated structures with excellent electrochemical properties and mechanical flexibility. A composite film with high strength and flexibility is created using graphene (reduced graphene oxide (rGO)) as the plane layer, layered double metal hydroxide (LDH) as the support layer, and cellulose nanofiber (CNF) as the connection agent and flexible agent. The interlayer height can be adjusted by the ion concentration. The highly interconnected network enables excellent electron and ion transport channels, facilitating rapid ion diffusion and redox reactions. Moreover, the high flexibility and mechanical properties of the film achieve multiple folding and bending. The CNF-rGO-NiCoLDH film electrode exhibits high capacitance performance (3620.5 mF cm-2 at 2 mA cm-2), excellent mechanical properties, and high flexibility. Notably, flexible all-solid assembled CNF-rGO-NiCoLDH//rGO has an extremely high area energy density of 53.5 mWh cm-2 at a power density of 1071.2 mW cm-2, along with cycling stability of 89.8% retention after 10 000 charge-discharge cycles. This work provides a perspective for designing high-performance energy storage materials for flexible electronics and wearable devices.

Innovative design of silicon-core mesoporous carbon composite for high performance anode material in advanced lithium-ion batteries

Silicon is widely recognized as an exceptionally auspicious anode material for lithium−ion batteries due to its remarkable specific capacity, suitable operational potential, and ecologically innocuous characteristics. This study presents a novel silicon@void@FC (fibrous carbon) composite anode material for lithium-ion batteries. Utilizing a one-step synthesis approach, the resulting hollow core–shell structure, combined with a mesoporous carbon shell, demonstrates exceptional electrochemical performance. The Si@Void@FC electrode exhibits remarkable cycle stability and rate performance, maintaining structural integrity over 500 cycles without observable degradation. The outer carbon shell acts as a protective layer and accommodates silicon volume expansion during cycling, preventing excessive contact with the electrolyte. The rich mesoporous structure facilitates efficient lithium-ion diffusion, enhancing lithiation and delithiation processes. The simplified one-step synthesis method further streamlines the preparation process, eliminating the need for complete silica template formation. This innovative Si@Void@FC composite material holds promise for advancing lithium-ion battery technology, addressing challenges associated with silicon-based anode materials, and offering insights into the design and synthesis of high-performance energy storage materials.

Confined grotthuss proton-conduction along polyoxometalate chains inside carbon nanotubes for high-rate charge storage

Redox-active materials with excellent rate capability and cycling performance are in highly demand for electrochemical energy storage and conversion applications. Here, we unveil the confined proton-conduction behavior of one-dimensional polyoxometalate chains inside single-walled carbon nanotubes (SWNTs). The polyoxometalate molecules including phosphomolybdic acid {HPMo} and phosphotungstic acid {HPW} are encapsulated within SWNTs via host–guest recognition, driven by the electron transfer from nanotubes to polyoxometalates. Impressively, the redox hybrids of polyoxometalate@SWNTs deliver abnormal rate performance in acidic solution with capacity retentions over 73 % at high sweep rate of 1000 mV s−1, relative to the capacity at 10 mV s−1. This value is comparable to that of the pure SWNTs, typically known as double-layer capacitive materials. Electrochemical analyses reveal the Grotthuss proton-conduction mechanism of {HPMo} in SWNTs with a low activation energy of 0.11 eV. Therefore, the {HPMo}@SWNT hybrid demonstrates quasi diffusion-free characteristic with dominant capacitive contribution over 60 % at different sweep rates. Molecular dynamic simulations and density functional theory calculations evidence the strong burst-like transport of protons in the {HPMo}@SWNT hybrid. This process is dynamically favored in the continuous and long-range hydrogen-bond network along polyoxometalate chains with bound/free water molecules inside SWNTs. The superiority of nanoconfined Grotthuss mechanism may engender an exciting avenue for developing high-performance energy storage materials.

Electrical and structural engineering of nanoflower-like NiMn-layered double hydroxide by V modulation for high-performance hybrid supercapacitors

This work produced V-doped NiMn-layered double hydroxide(V-NiMnLDH) composite positive electrode material directly on nickel foam using a simple one-step hydrothermal synthesis process. The composite's 3D nanoflower-like design increased spatial utilization, surface area, and active sites for Faradaic redox reactions. The composite material has a specific capacitance of 1551 F g−1 at 1 A g−1 and 85.6 % capacitance retention at 10 A g−1, demonstrating exceptional cycle stability. In addition, we combined V-NiMnLDH with commercial activated carbon to create an asymmetric supercapacitor (ASC) with 63.5 Wh kg−1 energy density and 975 W kg−1 power density. After 5000 charge-discharge cycles, the gadget preserved 89.7 % of its specific capacitance. This material outperforms similar electrode materials in certain performance evaluations. We also used density functional theory (DFT) computations to analyze each element in the V-NiMnLDH composite and explain their electronic density of states contributions. This theoretical framework explains how V doping improves capacitance. Band structure simulations also showed V-NiMnLDH's higher charge transfer and conductivity compared to intermediate products, explaining its extraordinary capacitance performance. Our work combines theoretical and experimental data to advance catalyst design and high-performance energy storage materials.

Screening of organic lithium precursors for producing high-performance Li4SiO4-based thermochemical energy storage materials: Experimental and kinetic investigations

Thermochemical energy storage by using Li4SiO4 TCES materials has been considered a promising technology for efficient heat storage from high temperature sources (700–900 °C). It has been proven the utilization of organic lithium precursors could effectively improve the heat storage performance of derived Li4SiO4. Hence, in this work, 7 kinds of unreported organic lithium precursors were screened for producing high-performance Li4SiO4 TCES materials. The physicochemical properties, CO2 ad-desorption capacities and the heat storage/releasing performance of as-prepared Li4SiO4 were systematically evaluated by a series of experimental and kinetic investigations, and a dual modification effects of organic lithium precursor were revealed. As a consequence, 3 potential candidates including lithium benzoate, lithium oxalate and lithium citrate were screened out. Li4SiO4 adsorbents derived from these precursors show great heat storage amount promotions of over 50 % in comparison with the average capacity of traditional Li4SiO4 (~ 350 kJ/kg/cycle). Especially, the lithium citrate derived Li4SiO4 exhibits the greatest CO2 adsorption capacity, reaction rate and cyclic stability, leading to a cumulative storage amount of 5.9 MJ/kg within 10 cyclic heat storage/releasing processes. Above findings could provide guidance for the future development of high-performance Li4SiO4 materials and Li4SiO4-CO2 TCES systems.

Harnessing deep eutectic solvents for upcycling waste membranes into high-performance adsorbents and energy storage materials

Polymer membranes waste management across the globe is a great concern due to the lack of advancement in upcycling methods. Herein, waste polysulfone (W-PSF) membranes, an emerging environment threat, have been converted to multi-functional carbon materials via green method using choline chloride:FeCl3 (CC:FeCl3) based deep eutectic solvent (DES) systems through solvothermal reaction followed by pyrolysis at 900 °C. The optimized material (Fe-WPSF-01) showed excellent adsorption capacity towards Malachite green (MG), Congo red (CR), Amoxicillin (Amo), and Bisphenol-A (BPA) with 515, 407, 216, and 322 mg/g of adsorption capacity, as calculated from the well-fitted Langmuir isotherm. Further, an easy-to-use adsorptive membrane filtration method was established to investigate the robustness of Fe-WPSF-01 in removing the above pollutants in continuous flow method. The resultant flux rate was 700–815 L.m−2.h−1 with rejection rates of 99, 98, 92, & 98 % for MG, CR, Amo, & BPA, respectively. Besides, the material showed recyclability for up to 10 cycles with 92.1 & 81.2 % of rejection rates for MG and Amo. After the potential usage of carbon material in adsorption studies, secondary materials were again pyrolyzed to use as an electrode in supercapacitors with a specific capacitance of 215 F/g at a current density of 0.1 A/g. Electrode showed capacity retention of 97.51 % even after about 20,000 cycles at an increased current density of about 5 A/g. Thus, a potential sustainable approach of upcycling the W-PSF membranes for energy and environmental applications are well-presented in this work.

Investigating the electronic properties of PANI/graphene/PVDF/PTFE nanocomposite

Manufacturing of clean energy is an important topic of research for modern life. This paves the way toward investigating easy manufacturing; high-performance energy storage materials. In this sense, conducting polymers such as polyaniline (PANI) are modified with graphene (G) then bound with poly vinylidene fluoride (PVDF) and poly tetrafluoro ethylene (PTFE) to enhance their electronic properties to be used as electrode material in energy storage applications. Furthermore, molecular modeling based on density functional theory at B3LYP/LanL2DZ level of theory was utilized to study the interaction between PANI; G; PVDF and PTFE. Some important properties are calculated such as the total dipole moment (TDM), HOMO/LUMO energy gap (ΔE), and molecular electrostatic potential (MESP). TDM of PANI was found to be 3.994 Debye and increased to 6.010, 9.012, and 9.822 Debye for PANI/G/PTFE, PANI/G/PVDF/PTFE, and PANI/G/PVDF, respectively. ΔE of PANI is 4.353 eV and decreased because of the interaction of PANI with G and polymer binders to reach 3.507, 3.095, and 2.127 eV for PANI/G/PTFE, PANI/G/PVDF, and PANI/G/PVDF/PTFE, respectively. From MESP result, the reactivity and electronic properties increased with the interaction of PANI with G and polymer binders. PANI/G/PVDF/PTFE composite was dedicated as the most suitable candidate for electrode material for many applications.

High-energy-density, ultralong-life manganese oxide composite carbon aqueous zinc-ion asymmetric supercapacitors

Transition metal oxide composites integrate the characteristics of metal oxides and carbon materials, thereby combine the advantages of both battery-type and capacitive electrodes. Using bimetallic aluminum‑manganese metal-organic frameworks (MOFs) as precursors, the MOFs are calcined under a nitrogen atmosphere, followed by etching in a sodium hydroxide solution to obtain the MnO/C (MO/C) composite material. The resulting high specific surface area composite material (583.76 m2 g−1) exhibits outstanding electrochemical performance, achieving a high energy density of 146 Wh kg−1 and a power density of approximately 1000 W kg−1 at a current density of 1 A g−1, along with excellent stability. Even under a high current density of 10 A g−1 and after 5000 cycles, the material maintains a capacitance retention rate of 96.7 %. The high specific surface area and abundant pore structures provide more electrochemical active sites, facilitating ion diffusion. The carbon framework enhances conductivity, effectively mitigating structural collapse caused by volume expansion during repetitive charge and discharge processes, thereby improving material stability. This study provides robust support for the development of high-performance electrochemical energy storage materials.

BaTiO3-based lead-free relaxor ferroelectric ceramics for high energy storage

Barium titanate (BaTiO3, BT) is widely used in capacitors because of its excellent dielectric properties. However, owing to its high remanent polarisation (Pr) and low dielectric breakdown field strength (Eb), achievement of high energy storage performance is challenging. Herein, a systematic strategy was proposed to reduce Pr and elevate Eb of BT via: (i) modification of the relaxor behavior by alloying it with Bi(Mg2/3Ta1/3)O3 (BMT) and (ii) heightening Eb by introducing NaTaO3 (NT) with high band gap. Consequently, the energy storage efficiency (η) of 90 % and high Eb of 780 kV cm−1 were achieved simultaneously for the BT-BMT-xNT system, which facilitated the recoverable energy density (Wrec) of 6.02 J cm−3. At 300 kV cm−1, its temperature (20–120 °C) and frequency (1–500 Hz) stabilities were found to be good. Moreover, the BT-BMT-0.15NT possessed ultrafast discharge rate (t0.9 < 51 ns) and ultrahigh power density (PD > 94 MW cm−3). This study offers an effective strategy for the design of novel high-performance dielectric energy storage materials.

GQD-PAN-based high-performance supercapacitor: an approach towards wealth from waste

Conversion of styrofoam waste into high-performance energy storage material: graphene quantum dots coated cPAN matrix yields 78 times capacitance improvement.

Crystallization of amorphous anodized TiO2 nanotube arrays.

Anodized TiO2 nanotube arrays (TNTAs) prepared by anodization have garnered widespread attention due to their unique structure and properties. In this study, we prepared TNTAs of varying lengths by controlling the anodization time. Among them, the nanotubes anodized for 2 h have an inner diameter of approximately 92 nm and a wall thickness of approximately 12 nm. Then we subjected amorphous TNTAs prepared by the anodization method to annealing treatments, systematically analyzing the evolution of morphology and structure with varying annealing temperatures. As the annealing temperature increases, the amorphous successively undergoes transitions to the anatase phase and then to the rutile phase. During the transition to the anatase phase, the structure of the nanotube array remains intact, with the complete preservation of the tubular array structure. However, during the transition to the rutile phase, the tubular array structure is destroyed. To address why the tubular array remains undamaged during the amorphous-to-anatase transition, we subjected amorphous TNTAs to annealing at 300 °C for different durations. Raman spectroscopy was employed for fit analysis, providing insights into the evolution of the molecular structure during the anatase phase transition. Finally, TNTAs annealed at different temperatures were incorporated into lithium-ion batteries. By combining XRD for semi-quantitative phase content and anatase particle size calculations, we established a correlation between structure and electrochemical performance. The results indicate a significant improvement in electrochemical performance for an amorphous-anatase structure obtained through annealing at 300 °C, providing insights for the design of high-performance energy storage materials.

The Li2Ti6O13 and Li2Zr6O13 composite as a high-performance anode for alkali-ion batteries: a molecular dynamics study.

The current development of technology has highlighted the necessity of compounds that enhance the durability and performance of alkali-ion batteries. The anodes of these batteries need to overcome the challenges of low dc-conductivity at ambient temperatures and interfacial resistance between the solid-state electrolyte. By conducting large-scale molecular dynamics simulations, we investigated the transport properties of Li2Ti6O13 and Li2Zr6O13 mono- and bi-crystals, as well as Li2Ti6O13@Li2Zr6O13 composites. While the monocrystalline and bi-crystalline Li2Zr6O13 show similar transport properties, the composite materials, combining both compounds, exhibit the highest diffusion coefficients and dc-conductivity. The transport properties of the composite materials are found to be significantly higher than those mono- and bi-crystalline samples due to the Li interstitial mechanism and the presence of grain boundaries. Our study offers valuable insights for the development of high-performance energy storage materials.

Exploring the potential of MB2 MBene family as promising anodes for Li-ion batteries.

In recent years, finding high-performance energy storage materials has become a major challenge for Li-ion batteries. B-based two-dimensional materials have become the focus of attention because of their abundant reserves and non-toxic characteristics. A series of two-dimensional transition metal borides (MBenes) are reported and their electrochemical properties as anode materials for Li-ion batteries are investigated by density functional theory (DFT) calculations. The surface of MB2 possesses medium adsorption strength and diffusion energy barrier for Li atoms, which are conducive to the insertion and extraction of Li-ions during the charge/discharge process of Li-ion batteries. Herein, we explore the potential of MB2 (M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu and Zn) as the anode material for LIBs. Excitingly, the Li atom can be stably adsorbed on the surface of MB2 (M = Sc, Ti, V, Nb, Mo, W) monolayers, and the theoretical capacity of the MB2 monolayer is high (521.77-1610.20 mA h g-1). The average open circuit voltage range is within 0.10-1.00 V (vs. Li/Li+). The relationship between the p-band center of the B atom and the adsorption energy of Li on the surface of MB2 is also investigated. Furthermore, it is found that the charge transfer of Li atom and metallic center in the most stable position is strongly related to the corresponding value of diffusion energy barrier. These results confirm that MB2 monolayers are promising 2D anode materials for Li-ion batteries, demonstrating the application prospects of B-based 2D materials.

Acoustic Shock Wave-Induced Solid-State Fusion of Nanoparticles: A Case Study of the Conversion of One-Dimensional Rod Shape into Three-Dimensional Honeycomb Nanostructures of CdO for High-Performance Energy Storage Materials.

Herein, we describe the solid-state fusion of rod-shaped to honeycomb-shaped cadmium oxide particles (CdO NPs) caused by the process of repeated exposure to acoustic shock waves. Significant changes have been observed in structurally and morphologically dependent properties. For instance, at the 200-shocked condition, the high-pressure CdO-B2 phase is present as a secondary phase wherein all of the rod-shaped particles have been transformed into honeycomb-shaped CdO particles which possess comparatively higher specific-capacitance than CdO nanorods (NRs). The computed specific capacitance values for the 0, 100, and 200 shocked samples at a scan rate of 100 m V s-1 are computed to be 433, 415, and 583 F g-1, respectively. The second-stage decomposition temperature points of the CdO NPs have significantly increased in accordance with the morphological changes from rod to honeycomb patterns such that the values are 343, 526, and 534 °C, respectively, for 0, 100, and 200 shocked conditions. Note that such honeycomb nanostructured CdO particles by shock-wave processing have never been observed, to date. Due to the superior energy storage abilities as well as the spectacular high thermal stability of the honeycomb CdO nanostructures compared to CdO NRs, shocked CdO with honeycomb nanostructures can be considered as energy storage materials.

Mild and Efficient One-Step Synthesis of Nitrogen-Doped Multistage Porous Carbon for High-Performance Supercapacitors.

Biomass-derived carbon materials have broad application prospects in energy storage, but still face problems such as complex synthesis paths and the massive use of corrosive activators. In this study, we proposed a mild and efficient pathway to prepare nitrogen-doped porous carbon material (N-YAC) using one-step pyrolysis with solid K2CO3, tobacco straw, and melamine. The optimized material (N-YAC0.5) was not only enriched with nitrogen, but also exhibited a high specific surface area (2367 m2/g) and a reasonable pore size distribution (46.49% mesopores). When utilized in electrodes, N-YAC0.5 exhibited an excellent capacitance performance (338 F/g at 1 A/g) in the three-electrode system, and benefitted from a high mesopore distribution that maintained a capacitance of 85.2% (288 F/g) at high current densities (20 A/g). Furthermore, the composed symmetric capacitor achieved an energy density of 14.78 Wh/kg at a power density of 400 W/kg. In summary, our work provides a novel and eco-friendly approach for converting biomass into high-performance energy-storage materials.