High Degree Of Graphitization Research Articles

Morphological modulation of iron carbide embedded nitrogen-doped hierarchically porous carbon by manganese doping as highly efficient bifunctional electrocatalysts for overall water splitting

In the development of water splitting, the sluggish electrocatalytic kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have restricted their energy conversion efficiencies. Along with the continuous rise in the prices of noble metals and transition metals (such as cobalt and nickel), constructing high-efficiency HER/OER catalysts based on low cost transition metals, such as iron and manganese, is becoming more meaningful in developing industrialized water splitting devices. In this paper, in the absence of a template or active agent, three-dimensional, hierarchically porous FexMny nanoparticles (NPs) were embedded and nitrogen-doped carbon materials (denoted as FexMny@NC; x:y, representing the molar ratio of Fe:Mn) were successfully prepared via pyrolysis of corresponding precursors containing different metallic salt components. Various morphological, structural, and chemical characterization analysis demonstrate that at an Fe:Mn molar ratio of 3:1, the optimal Fe3Mn1@NC material shows high graphitization degree, rich mesoporous structures, a large surface area, and abundant carbon defects/edges, which promote the uniform dispersion of pyridinic-N (pyridinic-N-metal), graphitic-N, carbon oxygen bonds (CO), manganese oxide (MnO) nanocrystals, and Fe3C NPs-embedded, N-doped carbon sheet (Fe3C@NC) active sites. In alkaline conditions, the HER onset potentials (Eonset) and potentials recorded at 10 mA cm−2 (E10) of the optimal Fe3Mn1@NC are just 84.8 and 156 mV more negative than those of 20 wt% platinum carbon (Pt/C). Meanwhile, the OER Eonset and E10 values of the optimal Fe3Mn1@NC are just 8 and 18.7 mV more positive than those of RuO2. Furthermore, optimized Fe3Mn1@NC catalysts were assembled into a water splitting cell, where the catalytic current density achieves 10 mA cm−2 at a low voltage of 1.6287 V (with superior catalytic stability), which is just 24.9 mV higher than that of the (-) 20 wt% Pt/C||RuO2 (+) benchmark (1.6038 V) under the same conditions. This work describes the regulating efficiency of Mn toward growing mesopores and opens new possibilities for the development of novel carbonaceous catalysts with excellent hydroxide catalytic efficiencies based on low cost Mn/Fe elements.

Near net-shape fabrication and properties of graphitic carbon foam with a continuous network of graphite nanosheets

A near net-shape graphitic carbon foam (GCF) with a continuous network of graphite nanosheets was prepared by direct carbonization of epoxy resin filled with nano-Al2O3. The effects of carbonization temperature on the properties of the resulting carbon foams were investigated by SEM, TEM, XRD, Raman, thermal conductivity and compression strength test. The results show that the as-prepared GCF can maintain well dimensional stability upon carbonization. The carbothermal reaction between the nano-Al2O3 and carbon foam matrix greatly influences the microstructure of carbon foam and promotes its growth of the continuous network of graphite nanosheets. In addition, the GCF prepared at 1700 °C possesses a compressive strength of 2.34 MPa with a bulk density of 0.19 g cm-3, and meanwhile presents a high graphitization degree of 65.12% and a thermal conductivity of 2.02 W/mK. The continuous network of graphite nanosheets favors the enhancement of thermal conductivity of carbon foam and simultaneously prevents the decline of compressive strength further.

Multigraphene Prepared by One-Pot Pyrolysis of Diatomite/Polypropylene Composites

Multigraphene was prepared via a one-pot pyrolysis method using polypropylene (PP) as the carbon source and diatomite (DM) as the catalyst. The obtained graphene had 4–6 layers and a D/G intensity ratio of 0.70 and a 2D/G intensity ratio of 0.72, indicating a high degree of graphitization. When the pyrolysis temperature was higher than 850 °C under argon, the graphene yield was greatly dependent on the DM content. The highest graphene yield of 25.86% was obtained by pyrolysis of PP with 30 wt.% DM at the temperature of 1000 °C. A catalytic effect of DM and infusible cross-linking structure formation were proposed to explain the possible mechanism of graphene growth during the pyrolysis of the DM/PP composites.

Preparation and thermal conductivity enhancement of a paraffin wax-based composite phase change material doped with garlic stem biochar microparticles

The addition of thermally conductive nanomaterials is an effective strategy for increasing the thermal conductivity of phase change materials (PCMs). However, nanomaterials are expensive and may significantly reduce the latent heat capacity of PCMs. In this study, low-cost and eco-friendly biochar microparticles were prepared from garlic stems, a common food waste in Singapore. The thermal properties of paraffin wax (PW) doped with 1, 3, and 5 wt% garlic stem biochar (GSB) microparticles were investigated. The GSB microparticles prepared at 700 °C had three-dimensional porous and two-dimensional flake-like structures, which contributed to the formation of additional heat transfer pathways in the PW. The addition of 5 wt% GSB microparticles enhanced the thermal conductivity of PW by 27.3% and 7.2% in the solid and liquid phases, respectively. The T-history test revealed that the melting and solidification rates of PW improved by 90 and 115 s, respectively. The improved heat transfer performance was mainly ascribed to the high degree of graphitization and the interconnected porous carbon structure of the GSB microparticles. The phase change temperatures of PW were slightly changed upon the addition of GSB microparticles, and the latent heat capacity was only reduced by 6.1%. These results suggest that the GSB microparticles can be used as a potential alternative to other nanoadditives such as metal- and metal oxide-based nanoadditives.

Nickel Acetate-Assisted Graphitization of Porous Activated Carbon at Low Temperature for Supercapacitors With High Performances.

Catalytic graphitization opens a route to prepare graphitic carbon under fairly mild conditions. Biomass has been identified as a potentially attractive precursor for graphitic carbon materials. In this work, corn starch was used as carbon source to prepare hollow graphitic carbon microspheres by pyrolysis after mixing impregnation with nitrate salts, and the surface of these carbon microspheres is covered with controllable pores structure. Under optimal synthesis conditions, the prepared carbon microspheres show a uniform pore size distribution and high degree of graphitization. When tested as electrode materials for supercapacitor with organic electrolyte, the electrode exhibited a superior specific capacitance of 144.8 F g−1 at a current density of 0.1 A g−1, as well as large power density and a capacitance retention rate of 93.5% after 1,000 cycles in galvanostatic charge/discharge test at 1.0 A g−1. The synthesis extends use of the renewable nature resources and sheds light on developing new routes to design graphitic carbon microspheres.

Rigid polyurethane foam composites based on bivalent metal phytate: thermal stability, flame retardancy, and fire toxicity

ABSTRACT As the main form of phosphorus in plant seeds, phytic acid has potential value in flame retardant field. In this study, a series of bivalent metal phytate (PA-M) flame retardants were prepared using phytic acid and divalent metal salts as raw materials. FTIR, SEM-EDS, XRD, and TG tests confirmed that copper phytate (PA-Cu), zinc phytate (PA-Zn), cobalt phytate (PA-Co) and nickel phytate (PA-Ni) were successfully synthesized. Furthermore, flame retardant rigid polyurethane foam (RPUF/PA-M) composites were prepared by one-step water-blown technology using PA-M as flame retardant. TG test results showed that RPUF/PA-Cu30 had the highest char residue at 700 C, which was 26.2 wt%, significantly higher than 12.4 wt% of RPUF. Cone calorimetry, smoke density test, and TG-FTIR analysis confirmed that RPUF/PA-Co30 composite exhibited excellent smoke suppression and toxicity reduction performance when 30 phr PA-Co was added. Compared with RPUF, the THR, TSR, and SDR of RPUF/PA-Co30 were decreased by 13.9%, 27.3% and 43.9%, respectively, and the release of toxic gases (isocyanate compounds, aromatic compounds, CO and HCN) and combustible gases (hydrocarbons and esters) were significantly reduced. The analysis of char residues of RPUF/PA-M composites suggested that PA-M could promote the formation of dense carbon layer with high graphitization degree and improved the fire resistance of composites. This work provided a new way for fabricating fire safety RPUF composites.

Effect of Microstructures of Carbon Nanoproducts Grown on Carbon Fibers on the Interfacial Properties of Epoxy Composites.

Two kinds of carbon nanoproducts with different microstructures, namely, carbon nanotubes (CNTs) and carbon nanofibers (CNFs), were grown on the surface of carbon fibers (CFs) by chemical vapor deposition (CVD) at low temperatures to improve the interface bonding between fibers and resins. The short-beam method and the micro-debonding method were used to test the interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) of the composites. The results showed that the contribution of CNTs to the improvement of interfacial properties was better than that of CNFs. Specifically, the ILSS and IFSS of the CF-CNFs/epoxy composites increased by 18.59 and 24.39%, respectively, while the ILSS and IFSS of the CF-CNTs/epoxy composites increased by 26.97 and 47.79%, respectively. Compared with CNFs, the high degree of graphitization of CNTs and the π-interactions with the resin can better induce the formation of an interphase between the fiber and the resin, which suppressed the initiation of cracks and extended the propagation path of the cracks in the composites.

Boron and nitrogen co-doped carbon nanospheres for supercapacitor electrode with excellent specific capacitance

At present, carbon materials derived from biomass precursors have many limitations in the field of energy storage. In this study, boron and nitrogen (B/N) co-doped carbon nanospheres are successfully prepared by emulsion crosslinking method using chitosan and boric acid as raw materials. After carbonization at high temperature, the carbon nanospheres can be facilely prepared with controllable particle size, showing excellent structural stability and sphericity. In addition, the heteroatoms co-doping endows the carbon nanospheres with large specific surface area, high graphitization degree and excellent electrochemical performance. Applying the carbon nanospheres for supercapacitors, the specific capacitance can reach up to 336.7 F g−1 at a current density of 1 A g−1. Even after 10,000 cycles, the Coulomb efficiency and specific capacitance still remain at 98.61% and 96.8%, respectively, demonstrating the great promise of B/N co-doped carbon nanospheres for the state-of-the-art supercapacitor electrodes applications.

Co/N-codoped carbon nanotube hollow polyhedron hybrid derived from salt-encapsulated core-shell ZIF-8@ZIF-67 for efficient oxygen reduction reaction

The rational design and construction of non-precious metal-based electrocatalysts with high activity and stability toward oxygen reduction reactions (ORR) are essential but challenging. In this work, a novel hybrid nanoporous structure of Co nanoparticles uniformly embedded in hollow porous carbon doped with nitrogen (CoNHPC) was constructed by a melt-evaporation-pyrolysis method, in which NaCl is utilized as an auxiliary template. The introduction to NaCl in this process served as the confining template to prevent nitrogen loss and promote graphitization, and the intercalating agent to form a mesoporous product. Due to the composite hierarchical porous structure, higher graphitization degree, and desirable nitrogen bonding type, the as-prepared CoNHPC-920 presents outstanding ORR electrocatalytic activity in terms of a half-wave potential of 0.87 V (vs. RHE) and onset potential of 0.97 V (vs. RHE). The composite material also shows higher selectivity and outstanding durability with most transition metal porous carbon materials reported. The strategy proposed in this study may provide ideas about metal nitrogen-carbon type catalysts enriched with carbon nanotubes and bare leaky hollow structures of the construction of advanced ORR electrocatalysts, opening up a new pathway.

Highly conductive, hierarchical porous ultra-fine carbon fibers derived from polyacrylonitrile/polymethylmethacrylate/needle coke as binder-free electrodes for high-performance supercapacitors

Here, the treated ultra-fine needle coke particles (UNCs) are introduced in hierarchical porous ultra-fine carbon fibers by electrospinning and thermally treatment process of two immiscible polymers and UNCs precursor. The structure, morphology and electrochemical performance of the ultra-fine carbon fibers derived from polyacrylonitrile (PAN)/polymethylmethacrylate (PMMA)/UNCs are explored in detail. As a result, when the mass ratio of PAN to PMMA reaches 6: 4, the ultra-fine carbon fibers derived from PAN/PMMA/UNCs display a high surface area of 919.3 m 2 g −1 , a suitable mesoporous structure of meso/micro = 1.59. and exhibit a remarkable specific capacity (387.2 F g −1 at 0.5 A g −1 ) and excellent power performance. Furthermore, a comprehensive electrochemical performance of symmetrical supercapacitors was obtained: prominent energy density (27.87 Wh·kg −1 at 489 W kg −1 ) and ideal cyclic stability (97.5% capacity retention after 10,000 cycles at 1 A g −1 ). In addition, hierarchical porous ultra-fine carbon fibers derived from blend polymer and needle coke with high degree of graphitization, which provide a potential optional application for served as binder-free electrodes for electrochemical energy storage devices. • UNCs with high compatibility in electrospinning precursor were prepared. • The Free-standing carbon fiber electrodes show excellent performance. • The as-assembled supercapacitor exhibits high energy density and remarkable cycle life.

Turning carbon black into hollow carbon nanospheres to encapsulate Fe2O3 as high-performance lithium-ion batteries anode

Fe 2 O 3 are attractive anode materials for lithium-ion batteries because of their large theoretical capacity and low cost. However, due to their low conductivity, large volume variation and unstable solid electrolyte interface (SEI), their cycling stability is poor. Herein, we developed a simple and general strategy to address these issues. The well-designed yolk-shell Fe 2 O 3 @C nanospheres with the inner Fe 2 O 3 nanoparticles are protected by highly-graphitized and interconnected carbon shells prepared by oxidizing commercial acetylene black. The obtained yolk-shell Fe 2 O 3 @C nanospheres provide sufficient interior void to buffer the volumetric variation of the inner Fe 2 O 3 nanoparticles during cycling. Furthermore, the highly-graphitized and perforated mesoporous carbon shells facilitate fast electron transfer and ions transportation during the charge/discharge process. Benefiting from these structural advantages, the yolk-shell Fe 2 O 3 @C nanospheres provide good cyclic stability which still retain 929 mAh g −1 after 200 cycles at the current density of 0.1 A g −1 and elevate Li + diffusion coefficient from 3.867 × 10 −13 to 6.321 × 10 −11 m 2 s −1 . This work provides a new perspective to design the yolk-shell metal oxides@C framework for exploring the high-performance Li-ion batteries. • Acetylene blacks was constructed into hollow carbon nanospheres. • Unique chain structure and high graphitization degree of carbon shell provides an effective conductive network. • The obtained yolk-shell Fe 2 O 3 @C nanospheres provide sufficient interior void to buffer the volumetric variation of the inner Fe 2 O 3 nanoparticles during cycling. • Fe 2 O 3 @C still retain 929 mAh g −1 after 200 cycles and the Li + diffusion coefficient goes from 3.867 × 10 −13 to 6.321 × 10 −11 m 2 s −1 .

Two C-S bonds derived from carbons with different IG/ID values promote high sulfur loads and stable capacity storage

Carbon materials are always used as sulfur carriers in lithium-sulfur batteries. However, storage mechanism of carbon materials with different graphitization degree is different. Carbons with lower graphitization degree (IG/ID value) usually possess many defects and poor electrical conductivities. Carbon materials with high graphitization degree always possess less contact sites. Both two carbon materials are conducive to achieve sulfur loads. However, sulfur-loading capacities of two materials are different. In this paper, two carbon materials with different graphitization degrees are combined to form composite carbon materials. Studies show that composite carbon electrodes with suitable IG/ID values possess good sulfur-loading capacities (80%) because of high conductivity and defect contents. Two kinds of C-S bonds are produced after loading sulfur and both of them are conducive to stable production of polysulfides. One C-S bond is conducive to diffusion of lithium ions on electrode surface and the other C-S bond is conducive to rapid conversion of polysulfides. Under the performance of two C-S bonds, high capacity storage and good cycling stability can be achieved by electrodes under high sulfur-loading conditions.

Understanding efficient phosphorus-functionalization of graphite for vanadium flow batteries

Numerous surface treatment methods are known to enhance the electrochemical activity of graphite felt (GF), such as thermal activation or attachment of nanoparticulate catalysts. The integration of heteroatoms into the graphite lattice at the surface could be a promising technique for reliable and efficient electrode activation. However, these functionalization techniques are based on thermochemical activation, which makes it difficult to distinguish between activity effects other than foreign atom integration, such as defects and other surface groups that must be considered. In this work, we analyzed commercial and synthetic phosphorus-doped graphene and GF using different electrochemical and physicochemical techniques. Despite a high doping concentration, the activity of the commercial powder bonded to GF and coated on glassy carbon remained limited due to the low degree of graphitization and high oxygen content. Instead, a low phosphorus concentration of <1 at% combined with a high degree of graphitization increased the catalytic activity. Building on these findings, GF was rationally modified, resulting in twice the power density compared to the original material in full cell tests.

Hierarchical porous carbon induced by inherent structure of eggplant as sustainable electrode material for high performance supercapacitor

The conversion and utilization of renewable biomass have attracted worldwide focus on sustainable development research. The study of biochar as electrode material for supercapacitors shows that the hierarchical porous structure of biochar directly affects the performance of supercapacitors. Here, we utilize the instinct porous structure of eggplant to establish the carbon material with hierarchical porous structure by simple carbonization process. The resultant eggplant-derived hierarchical porous carbon (EHPC) materials possess high specific surface area (1947 m2 g−1), high graphitization degree, and low resistance, which brings good rate performance, excellent specific capacitance (469 F g−1 at 1 A g−1), high energy density at high power density (38.51 Wh kg−1 at 687.1 W kg−1 in organic system and 15.83 Wh kg−1 at 55.5 W kg−1 in aqueous system), great capacitance retention (90% at a high scan rate of 100 mV s−1), and long lifetime (99.95% after 20,000 cycles). The performance tests of the capacitors assembled by EHPC materials show that porous biomass offer huge advantages in the preparation of hierarchical porous carbon materials for supercapacitors electrode materials.

In situ engineering of highly conductive TiO2/carbon heterostructure fibers for enhanced electrocatalytic degradation of water pollutants

Rational design of nanocomposite electrode materials with high conductivity, activity, and mechanical strength is critical in electrocatalysis. Herein, freestanding, flexible heteronanocomposites were fabricated in situ by carbonizing electrospun fibers with TiO2 nanoparticles on the surface for electrocatalytic degradation of water pollutants. The carbonization temperature was observed as a dominant parameter affecting the characteristics of the electrodes. As the carbonization temperature increased to 1000 °C, the conductivity of the electrode was significantly enhanced due to the high degree of graphitization (ID/IG ratio 1.10) and the dominant rutile phase. Additionally, the formation of TiO2 protrusions and the C-Ti heterostructure were observed at 1000 °C, which contributed to increasing the electrocatalytic activity. When 1.5 V (vs. Ag/AgCl) was employed, electrocatalytic experiments using the electrode achieved 90% degradation of crystal violet and 10.9–87.5% for an array of micropollutants. The electrical energy-per-order (EEO) for the removal of crystal violet was 0.7 kWh/m3/order, indicative of low-energy requirement. The efficient electrocatalytic activity can be ascribed to the fast electron transfer and the strong ability to generate hydroxyl radicals. Our findings expand efforts for the design of highly conductive heteronanocomposites in a facile in situ approach, providing a promising perspective for the energy-efficient electrocatalytic degradation of water pollutants.

Silk-Waste-Derived Porous Carbon for Fast Electric Heating under Safe Voltage

Fast and safe electric heating is highly needed in extreme climates or thermal therapy. Herein, porous activated carbon derived from silk waste is prepared by a simple method. Various porous activated carbons are obtained using different types and concentrations of activator (KOH, KCl, and KHCO3). The effect of the microstructure on the electric heating performance of these carbons is investigated carefully. The type, activator concentration, and carbonization temperature play key roles in the regulation of electric heating properties. The porous carbon activated by 0.05 M KHCO3 at 800 °C demonstrates larger specific surface area (3077 m2 g-1), higher graphitization degree, and lower resistance (2.4 Ω cm), which synergistically contribute greatly to its higher electrothermal efficiency and better electric heating performance. The equilibrium temperature could reach 73 °C in 2 min under a safe voltage of 12 V, proving the better pore-forming capacity and activating function of KHCO3. An electric heating cotton@carbon composite fabric with quite good electric heating property and stability is also prepared, which could reach 38 °C in 2 min under 12 V safe voltage and maintain a temperature 10 °C higher than the ambient temperature even when bent at an angle of 55°. This activated carbon derived from waste protein using a simple and cheap process has great potential in practical applications.

Nitrogen-doped carbon nanosheets with Fe-based nanoparticles for highly efficient degradation of antibiotics and sulfate ion enhancement effect

Developing Fe-based catalysts with high-effective and environmentally friendly features in Fenton-like system for treating wastewater is still a challenge. Novel nitrogen-doped carbon nanosheets with Fe0/Fe3C nano-particles (Fe@NCS-900) were prepared through a simple solvent-free strategy by pyrolyzing the mixture of 2,6-diaminopyridine and ferric chloride hexahydrate under 900 °C. The Fe@NCS-900 possessed almost 100% removal efficiency and 66.5% mineralization rate for the degradation of CBZ in 10 min. Moreover, the Fe@NCS-900 exhibited an apparent first-order constant as high as 0.8809 min−1, which is 22 and 29 times higher than that of the commercial Fe0 and traditional Fenton system, respectively, which could be attribute to the high graphitization degree and rich nitrogen content. Besides, the results of the radical quenching experiments, electron paramagnetic resonance (EPR) and the probe experiments demonstrated that a large number of high valent iron species (Fe (IV)) besides singlet oxygen (1O2) and superoxide radicals (O2•-) existed and contributed to the CBZ degradation. More interestingly, the addition of coexisting anion SO42− in the reaction system could significantly boost the concentration of •OH and SO4•- by 28.3 times and 9.7 times, respectively, resulting in the increase of the apparent first-order constant by 5.9 times (5.1733 min−1), which was entirely different from previous reports that SO42− had no effect on the catalytic activity or even displayed slightly inhibitory effect. In addition, the catalyst exhibited broad pH adaptability in the pH range of 2–9. The intermediate products of CBZ degradation were investigated by liquid chromatography mass spectrometry (LC-MS) and the degradation pathway was proposed. This paper provides new insights for developing a promising Fe-based nitrogen-doped catalyst for practical wastewater treatment.

Structure evolution of lignite char in step pyrolysis and its combustion reactivity

Step pyrolysis was conducted in a laboratory-scale fixed bed reactor for char preparation. Characterization techniques such as volume solvent swelling, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were applied to reveal char structure evolution during step pyrolysis. Combustion reactivities of the prepared chars were examined at a thermal gravimetric analyzer. Newly formed bond structures in char such as Cal-Cal and Car-Cal/O have been identified at the 1st stage of step pyrolysis, which evidences the occurrence of cross-linking reactions. As a result, step pyrolysis has higher char yield than direct pyrolysis. The char yield from step pyrolysis increases as the 1st stage pyrolysis temperature increases and reaches a maximum at 773 K. An index was put forward to assess the extent of cross-linking reactions during pyrolysis, which is well correlated with char production. The char from step pyrolysis has relatively high graphitization degree than from direct pyrolysis, and thus has lower combustion reactivity. Step pyrolysis can suppress sulfur and nitrogen release in comparison with direct pyrolysis owing to the formation of more stable sulfur and nitrogen species in char. The difference in nitrogen release varies within 8 percentage points and for sulfur release, it is within 5 percentage points under the examined experimental conditions.

Thick Si-Doped DLC Coatings With High Load Bearing Capacity on Cold Working Tool Steels by PECVD

Abstract For improving the wear resistance, thick silicon doped hydrogenated amorphous carbon (a-SiC:H) coatings were deposited on cold working tool steels by plasma-enhanced chemical vapor deposition (PECVD) technology. The increase of the acetylene (C2H2) flow rate distinctly tuned the microstructure of a-SiC:H coatings, including an increase in the coating thickness (&amp;gt;15 µm), a decrease in the silicon content, a greater sp2/sp3 ratio, and higher degree of graphitization. The highest hardness of 19.61 GPa and the greatest critical load of 50.7 N were obtained. The coating showed low wear rate against different friction pairs and presented excellent abrasive wear resistance at high applied load and the wear rate decreased with increasing loads, which exhibited an outstanding application prospect in cold working tool steels.

All-cellulose-based quasi-solid-state supercapacitor with nitrogen and boron dual-doped carbon electrodes exhibiting high energy density and excellent cyclic stability

The key to construct high-energy supercapacitors is to maximize the capacitance of electrode and the voltage of the device. Realizing this purpose by utilizing sustainable and low-cost resources is still a big challenge. Herein, N, B co-doped carbon nanosheets are obtained through the proposed dual-template assisted approach by using methyl cellulose as the precursor. Due to the synergistic effects form the high surface area with the hierarchical porous structure, N/B dual doping, and a high degree of graphitization, the resultant carbon electrode exhibits a high capacitance of 572 F g−1 at 0.5 A g−1 and retains 281 F g−1 at 50 A g−1 in an acidic electrolyte. Furthermore, the symmetric device assembled using bacterial cellulose-based gel polymer electrolyte can deliver high energy density of 43 W h kg−1 and excellent cyclability with 97.8% capacity retention after 20 000 cycles in “water in salt” electrolyte. This work successfully realizes the fabrication of high-performance all-cellulose-based quasi-solid-state supercapacitors, which brings a cost-effective insight into jointly designing electrodes and electrolytes for supporting highly efficient energy storage.