Carbon Cotton Research Articles

Dual-modified catalytic core-shell structure biomass carbon cotton fiber extends broadband electromagnetic waves absorption applications

Using vacuum impregnation method, the biomass carbon cotton fiber material was modified with polymer-derived SiCN ceramics and different Ni sources to successfully prepare the composite material. The electromagnetic microwave absorption properties of the material in the range of 2–18 GHz and the catalytic effect of different nickel sources were studied. The material modified by nickel nitrate hexahydrate forms a carbon fiber coated structure, improves impedance matching, enriches heterostructures, and increases electromagnetic synergistic loss, effectively enhancing the effective absorption bandwidth (EAB) reaches 4.72 GHz, the minimum reflection loss (RLmin) is −47.79 dB, and the thickness is only 1.32 mm. The results of CST show that the radar cross section of CFPN-2 material is −36.86 dB m2, and it has obvious effect of optimizing impedance matching.

Using Carbonized Cotton Fabric Waste to Prepare Poly(ethylene glycol) Composite Phase Change Materials with Improved Thermal Conductivity and Solar-to-Thermal Conversion.

Poly(ethylene glycol) (PEG) boasts excellent thermal energy storage capabilities but lacks efficiency in thermal conductivity and solar absorption. Simultaneously, the escalating concern surrounding the substantial volume of discarded cotton fabric underscores environmental issues. In this study, we devised composite phase change materials (PCMs) by embedding PEG into a carbon cotton material (CCM), varying PEG content from 50 to 80%, and conducted a comprehensive analysis of their thermal properties and solar-to-thermal conversion. The CCM, crafted from a waste 100% cotton towel through carbonization, provided an optimal porous structure that accommodated a significant 70% PEG content without any leakage, thanks to interactions such as surface tension, capillary forces, and interfacial hydrogen bonds. These PEG/CCM composites exhibited impressive crystallization fractions (>92%), resulting in notable thermal energy storage capacities ranging from 85.3 to 143.2 J/g as the PEG content increased from 50 to 80%. Moreover, these composites showed high thermal stability and exceptional cycling durability even after 500 melting/crystallization cycles. Notably, their thermal conductivities markedly increased to a range of 0.46-0.85 W/m·K compared to pure PEG's modest 0.24 W/m·K. Furthermore, the PEG/CCM composites substantially augmented visible and near-infrared (VIS-NIR) light absorption. Evaluation of solar-to-thermal conversion illustrated the composite's ability to efficiently convert solar energy into thermal energy, storing and subsequently releasing it through melting and crystallization processes. This study introduces a novel class of composite PCMs characterized by cost-effectiveness, outstanding thermal performance, and impressive solar-to-thermal conversion capabilities. These composite PCMs hold significant promise for large-scale solar-to-thermal energy storage applications while contributing to the sustainability of cotton waste management.

Enhancing performance of lithium-sulfur batteries through porous carbon network integration in carbonized cotton

A novel material, Cporous@CC, has been developed by incorporating a porous conductive network into carbonized cotton (CC). This modification significantly enhances the surface area of the material, increasing it from 29.1 to 163.0 m2 g−1. The introduction of the porous network significantly enhances the connection between carbon fibers, resulting in a substantial improvement in electronic conduction, up to 2–3 times greater than bare CC. To evaluate its potential, Cporous@CC was utilized as a conductive host for the cathode-active material in lithium-sulfur batteries. The battery utilizing Cporous@CC as the cathode host demonstrated a higher initial capacity of 1200 mAh g−1 at 0.2C and exhibited superior rate capability across the range of 0.1C to 1.0C, outperforming the CC-based battery. The factors contributing to the enhanced electrochemical performance of the Cporous@CC cell were further elucidated through the utilization of the galvanostatic intermittent titration technique.

Facile and Cheap Carbonized Cotton Cloth Interlayer Endows Lithium-Sulfur Batteries with High Performance in All Climates

Lithium-sulfur batteries (LSBs) have proven the potential for future power sources due to the ultrahigh theoretical specific capacity, material abundance, and eco-friendliness. However, the insulation of sulfur and the notorious shuttle effect of polysulfides impede the practical use. In this work, we introduced the hollow carbonized cotton cloth (CCC) as an interlayer by simple one-step carbonization. CCC reduces the charge transfer resistance and inhibits the shuttle effect, enabling LSBs with high rate and cycling performances in all climates. Specifically, the LSBs based on the CCC interlayer deliver rate capacities of 118, 399, and 879 mAh g–1 at 2 C at −30, 0, and 50 °C, respectively. Correspondingly in the 1 C cycling tests, the initial specific capacities are 168, 490, and 885 mAh g–1; the decay rates are 0.029% (1000 cycles), 0.034% (1000 cycles), and 0.056% (800 cycles). Moreover, with a higher sulfur loading of 2.3 mg cm–2, the ambient CCC battery achieves a decay rate of only 0.03% per cycle in the 1 C test (800 cycles). Compared with commercial carbon cloth, the ultralow price, light weight, easily scalable preparation, and all-climate good performance of CCC can extremely push LSBs to practical use in the future.

Hollow cotton carbon based NiCo2S4/NiMoO4 hybrid arrays for high performance supercapacitor

The design and preparation of new electrode materials with high conductivity and high energy density has become a frontier and key issue in the research of improving the performance of supercapacitor (SCs). Through the synergistic action of biomass carbon and transition bimetallic sulfide, the defects of pseudocapacitor electrode materials such as low conductivity and low energy density can be solved. On hollow cotton carbon (CC), a novel hybrid NiCo2S4/NiMoO4 arrays developed using a simple two-step hydrothermal procedure is reported. A series of characterization methods were used to characterize the samples.Experimental results demonstrated that the CC was hollow and the NiCo2S4/NiMoO4 arrays had uniformly grown on its surface. The sample demonstrated a high specific capacitance (2323 F·g−1 at a current density of 5 mA·cm−2) and outstanding electrochemical stability (90 % retention after 10,000 cycles), according to the electrochemical characteristics. Additionally, a hybrid asymmetric supercapacitor was assembled using CC/NiCo2S4/NiMoO4 (CNCNM) as the positive electrode, CC as the negative electrode, PVA/KOH as the separator and Nickel foam as current collector. The supercapacitor displayed a high energy density (86.52 Wh·kg−1 at 1006.65 W·kg−1), high specific capacitance (341.5 F·g−1 at 5 mA.cm−2), excellent cycling performance (85 % retention after 10,000 cycles), and a low charge transfer resistance. The energy storage capability was studied and a blue LED light (1.8 V) could be lit for 30 min by two similar devices connected in parallel.

Investigating the Performance of Solar Steam Generation Using a Carbonized Cotton-Based Evaporator

Solar-driven steam generation as a potential green technology has attracted extensive attention to solve the freshwater scarcity crisis. Photothermal materials as the key section of solar steam generation have been widely reported. However, there is still a challenge in developing easily prepared, environmental-friendly, and low-cost materials. Herein, the simple, scalable, and porous carbonized cotton was prepared as an evaporator to enhance solar-based evaporation, which has excellent light absorption ability in the range of the full spectrum (300–2,500 nm). Benefiting from 95% solar absorption and the pores between the cellulose tubes, the carbonized cotton heated by plate carbonization reaches a steam generation rate of 0.8 kg m−2 h−1, which is about 5 times that of untreated cotton. Compared with tube furnace carbonization, flat plate heating carbonization of cotton requires lower equipment requirements and does not need nitrogen protection and cleaning tar, and the photothermal conversion efficiencies of both are similar. In addition, carbonized cotton as an evaporator was heated up rapidly under 1 sun irradiation and reached a stable temperature in 20 s, greatly improving the photothermal conversion rate. Therefore, plate heating carbonized cotton provides a good idea for preparing solar photothermal conversion materials and a novel strategy for simplifying the production of biomass thermal evaporators.

Highly catalytic porous MoN nanosheets anchored carbon microtubes interlayer for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have been widely considered as one of the most promising next-generation energy storage devices owing to the ultrahigh theoretical capacity (1,672 mAh/g) and energy density (2,600 Wh/kg). However, the shuttle effect of lithium-polysulfides (LiPSs) and the sluggish conversion kinetics impede the wide commercialization of LSBs. In this work, porous and catalytic MoN nanosheets were fabricated on the conductive carbonized cotton cloth (denoted as CCC@MoN) to serve as an interlayer for LSBs. The porous structure of MoN nanosheets provides abundant catalytic sites to capture LiPSs and accelerates conversion kinetics. Notably, hollow and conductive fibers in CCC substrate can physically restrain LiPSs and serve as a secondary current collector to recycle the dissolved sulfur species. Thus, the highly catalytic porous MoN and conductive CCC can synergistically generate an efficient trapping-conversion ability toward polysulfides. With the assistance of the CCC@MoN interlayer, the LSBs exhibit remarkable cycling stability and rate performance. Even with a high areal sulfur loading (5 mg/cm−1) cathode, an impressive areal specific capacity of 4 mAh/cm−1 can still be achieved at 0.1 C. This work paves a new way for the design of multifunctional interlayers in the commercial application of LSBs.

Metal-free functionalized carbonized cotton for efficient solar steam generation and wastewater treatment.

Water desalination via solar steam generation is one of the most important technologies to address the increasingly pressing global water scarcity. Materials for solar photothermal energy conversion are highly sought after for their cost savings, environmental friendliness and broad utility in many applications including domestic water heating and solar-driven desalination. Herein, we report the successful development of metal-free, low weight and cost effective functionalized carbonized cotton (CC) fibers for efficient solar water desalination and wastewater treatment. The CC fibers with nearly full solar spectrum absorption, efficient photo-thermal conversion and low-cost could provide excellent alternatives to the high-cost plasmonic-based materials for solar water desalination. We also report on a novel and simple device to mitigate the issues associated with conductive heat loss by utilizing the economically viable carbonized cotton materials as an irradiation surface placed on a low-density polyethylene foam that floats on the surface of seawater. The CC solar steam generation device exhibits average water evaporation rates of 0.9, 6.4 and 10.9 kg m−2 h−1 with impressive solar-to-vapor efficiencies of 59.2, 88.7 and 94.9% under 1, 5 and 8 sun illumination, respectively. Moreover, the device displays excellent durability showing stable evaporation rates over 10 steam generation cycles under 5 sun of solar intensity. Furthermore, the applicability of the CC device for the removal of organic dyes from contaminated water through solar steam generation is also demonstrated. The low-cost, simple design, high solar thermal evaporation efficiency, excellent stability and long-term durability make this CC device a perfect candidate for applications in seawater desalination and wastewater treatment by solar steam generation.

Flexible and superhydrophobic carbonized cotton fabrics for effective electromagnetic interference shielding

A series of carbonized pure cotton fabrics and Ni@C nanocapsules decorated fabrics with plain-weaved structure were obtained by simple thermal treatment at different temperatures. The carbonized fabrics possess flexibility and stable hydrophobic characteristics. The carbonization temperature significantly affects the defects configuration and the migration and combination of atoms. The graphitization degree of the fabrics increases with the increase of carbonization temperature, which means an increase in electrical conductivity. The introduction of Ni@C nanocapsules results in the reaction of sulfur-philic nickel with the sulfur in the fabrics, thereby generating nickel-based sulfides with good electrical conductivity on the surface of the fabric fibers. The pure cotton fabrics carbonized at 800 °C and the Ni@C nanocapsules decorated fabrics carbonized at 700 °C and 800 °C have achieved nearly complete shielding of electromagnetic waves. The present work not only proposes an efficient process for electromagnetic interference shielding materials but also has great significance in understanding the structural origin of electromagnetic phenomena.

Porous carbonized cotton loaded with Zn–Cu–M(M=O, S) nanocomposites for electrochemical energy storage and oxygen evolution reaction

A new strategy has been designed for enhancing the electrochemical performances of the supercapacitor and water-splitting electrodes. Hetero-structure composite electrode based on copper sulfide (CuS), zinc oxide (ZnO), and porous carbonized cotton (PCc) is prepared via vacuum thermal evaporation technology and successive ionic layer adsorption methods. Porous substrate provides plenty of active sites, which facilitates the exchange of ions/charges in the electrode processes. The composite electrode exhibits outstanding electrochemical energy storage and electrocatalytic performances. The symmetrical supercapacitor as assembled reaches a high energy density of 0.27 Wh cm−2 at the power density of 3.34 W cm−2. By optimizing the composite structure, the energy barriers of the CuS/ZnO/PCc compound are reduced obviously in oxygen evolution reaction in comparison with pure PCc or CuS/PCc. The overpotential of the sample is decreased to 337 mV (10 mA cm−2 of the loop current) compared to that of PCc (492 mV) and CuS/PCc (415 mV). This work may inspire the rational design of composite electrode materials to achieve high performance in cross-field applications.

A new high-capacity cathode for all-solid-state lithium sulfur battery

A new composite sulfur cathode with high sulfur loading for all-solid-state lithium sulfur (LiS) battery, along with an in-situ coating process for preparing this composite cathode, is proposed in this manuscript. This composite cathode includes carbonized cotton fibers as the electron conductive skeleton, sulfide electrolyte coating on the carbon fibers as the Li-ion conductor, and elemental sulfur as the active material. The in-situ coating of sulfide electrolyte is carried out via a liquid-phase process, which results in a close contact between carbon fiber and the sulfide electrolyte. The subsequent mixing and heating treatment with elemental sulfur form a composite cathode with good electrochemical performance. In the assembled all-solid-state LiS battery with Li6PS5Cl electrolyte and lithium metal anode, the composite cathode delivers a super high discharge capacity of 32.8 mAh.

Reduced graphene oxide-coated carbonized cotton fabric wearable strain sensors with ultralow detection limit

The booming prosperity of strain sensors promotes the regeneration of wearable electronics. However, strain sensors featured with both large workable range and superb sensitivity are still less than satisfaction. Softness and practicality are also of vital importance for wearable electronics. In this work, a flexible wearable strain sensor based on carbonized cotton fabric coated with reduced graphene oxide (rGO) through polydopamine (rGO/PDA/CCF) modification was fabricated, which exhibits fascinating electrical mechanical performance including a large workable range and superb sensitivity. rGO/PDA/CCF was characterized using scanning electron microscopy (SEM), Raman scattering spectroscopy, and X-ray diffraction (XRD) patterns. The electromechanical performance of the rGO/PDA/CCF strain sensor was evaluated. The strain sensors of rGO/PDA/CCF exhibit a large workable strain range (0–120%) and superb sensitivity with strong durability over 800 cycles. The rGO/PDA/CCF strain sensor has a low detection limit down to 0.01% with a good gauge factor (GF) of 132 within the strain range of 0–1%, and also displays fantastic property in terms of sensitivity in other workable range (GF of 26 and 8 within in a strain range of 1–30% and 30–60%, respectively). rGO/PDA/CCF strain sensor was then applied to track the signal of human motions in real time. rGO/PDA/CCF flexible strain sensor can be utilized in detecting almost all human motions with various dimensions. Additionally, the hydrophobicity and the stability at different temperatures endow the rGO/PDA/CCF strain sensor with high efficiency in various usage, which shows its potential for application in health monitor and wearable electronics.

A novel high performance flexible supercapacitor based on porous carbonized cotton/ZnO nanoparticle/CuS micro-sphere

In this work, a novel flexible electrode composed of porous carbonized cotton, ZnO nanoparticles and CuS micro-spheres is prepared by two-step method. Benefitting from the synergistic effect of eletrochemical double layer capacitance and pseudo capacitance, the porous carbonized cotton/ ZnO/CuS composite (pCcZC) electrode shows excellent specific capacitance (1830 mF cm−2 at 2 mA cm−2), high rate performance (74% retention with the current density increasing from 2 to 10 mA cm−2) and outstanding cycle stability (14.8% loss of initial capacitance after 5000 cycles). The flexible and lightweight carbonized cotton as current collector directly makes the electrode binder-free, flexible and wearable. Additionally, the flexible symmetrical supercapacitor based on pCcZC electrodes achieves a superior energy density of 0.27 Wh cm−2 at 4.26 W cm−2, and can succesfully light the LED, which manifests its great applied potential in the new generation of portable and wearable energy storage devices.

Flexible and Conductive Carbonized Cotton Fabrics Coupled with a Nanostructured Ni(OH)2 Coating for High Performance Aqueous Symmetric Supercapacitors

Flexible and wearable supercapacitor (SC) fabrics have received considerable research interests recently. However, their high hydrophobicity, poor conductivity, inferior capacitance, and low energy density remain a bottleneck to be solved. Herein, a highly flexible and conductive carbonized cotton fabric (CCF) covered by a unique nanostructured Ni(OH)2 layer is fabricated via a facile high-temperature carbonization process, followed by an electrochemical deposition (ED) treatment. The nanostructured Ni(OH)2 greatly improves the hydrophilicity of CCF to promote electrolyte penetration and offers abundant electroactive sites, leading to dramatically increased specific capacitance and operating potential window (OPW). The resultant Ni(OH)2@CCF is then applied as the electrode for an aqueous symmetric SC device. This device has an OPW of 1.4 V and exhibits a high specific capacitance of 131.43 F g–1 at the current density of 0.25 A g–1 with a high energy density (35.78 Wh kg–1 at a power density of 0.35 kW kg...

Ammonia-assisted thermal activation of graphene-embellished biological fiber for flexible supercapacitors

Herein, we have demonstrated a scalable synthesis route to develop nitrogen-doped graphene embellished carbonized cottons (NGCs) via ammonia-assistant thermal activation processes combining with freeze-drying technique. It is found that the nitrogen-doped graphene (NG) nanosheets are well dispersed and cross-linked with the carbonized cotton skeleton fibers. The assistance of ammonia in thermal treatments can not only benefit the carbonization of the cotton and the reduction of the graphene oxide, but also make the nitrogen elements dope into the whole carbon composites. Due to the synergistic effect between the doped N functional groups and the highly conductive cross-linked networks, the NGCs electrodes exhibit a high capacitance (291 F g−1 at 1.0 A g−1) and a high cycle stability (almost no attenuation after 10,000 cycles). Furthermore, a type of lightweight and flexible symmetric supercapacitors was assembled, delivering a high energy density (5 W h kg−1 at 0.2 A g−1) and an excellent bending stability, which demonstrates its potential application in wearable energy storage devices.

Scaled-up process for producing longer carbon nanotubes and carbon cotton by macro-spools

A scaled up process of the longer carbon nanotube synthesis is reported. The developed suspended-bed synthesis rig is capable of producing carbon nanotube cotton in spools or piles in kilogram amounts. A possibility to produce free-standing non-woven nanotube thin films is demonstrated. The embryonation and initial growth periods are recorded. The carbon nanotube cotton was investigated by electron microscopy (SEM/TEM), Raman spectroscopy and thermal analysis. It was shown that the material is dominated by double-walled nanotubes. Opportunities of combing, roving and spinning the carbon nanotube cotton are discussed. In conclusion this successful scale-up development paves the way for intensification of the development in macroscopic carbon nanotube-based fibers and composite materials.

A facile synthesis of molybdenum carbide nanoparticles-modified carbonized cotton textile as an anode material for high-performance microbial fuel cells.

A novel macroscale porous structure electrode, molybdenum carbide nanoparticles-modified carbonized cotton textile (Mo2C/CCT), was synthesized by a facile two-step method and used as an anode material for high-performance microbial fuel cells (MFCs). The characterization results show that the carbonized cotton textile modified with Mo2C nanoparticles offers a great specific surface area (832.17 m2 g−1) for bacterial adhesion. The MFC using Mo2C/CCT anode delivers the maximum power density of 1.12 W m−2, which is 51% and 116% higher than that of CCT and unmodified carbon felt anodes under the same conditions. The high power density is mainly due to the Mo2C nanoparticles with good biocompatibility and high conductivity and superior electrochemical activity, as well as the macroscale porous structure of carbonized cotton textile, which facilitate the formation of electroactive biofilm and improve the electron transfer. This paper introduces a feasible way to synthesize cost-effective and high-performance anode materials for MFCs.

A highly active biomass-derived electrode for all vanadium redox flow batteries

In this work, we report an environmentally friendly and low-cost approach to synthesize an all biomass-derived electrode from cotton through a pyrolysis process and apply this novel electrode to a VRFB for the first time. It is demonstrated that this carbonized cotton (CC) electrode presents a higher BET surface area, a larger number of oxygen-containing functional groups, a better wettability and higher catalytic activity for vanadium reactions than commercial carbon papers (CPs) do. As a result, the CC electrode improves the reversibility toward VO2+/VO2+ by 100mV lower peak separation as compared with commercial CPs. Moreover, the VRFB assembled with the prepared electrodes delivers a high voltage efficiency of 75.4% at a current density of 100mAcm−2, outperforming the oxidized CPs (68.3%), and a better rate performance during the charge-discharge test at various current densities. These results suggest that the carbonized cotton electrode offers a great promise for the large-scale application in VRFBs.

Lithium-Sulfur Batteries with an Ultrahigh-Sulfur-Loading Carbon-Cotton Cathode

Going beyond lithium-ion chemistry, the lithium-sulfur (Li-S) chemistry could offer 2 – 3 times higher energy density than the current Li-ion battery technology.1,2 However, as reported in recent publications, the progress is far from adequate with respect to the high-loading capability of the active material in building high-energy-density Li-S batteries.1-3 Although the sulfur cathode has a high theoretical capacity (1,675 mA h g-1), a high-loading cathode fabricated by conventional electrode coating method has, unfortunately, proved it to be difficult to attain the necessary electrochemical conversion/utilization of sulfur. Given that a traditional cathode configuration is not ideal for a Li-S battery, advanced electrode structures have been extensively studied for increasing sulfur loading and achieving a high areal capacity.2,3 However, new challenges arise with respect to how to simultaneously improve the sulfur loading and maintain the dynamic and static cell stability.2,4 We present here a carbon-cotton cathode that possesses hierarchical macro-/micro-porous architecture for establishing the high-loading capacity of Li-S cells and simultaneously enhancing their dynamic and static stability.4 Fig. 1 shows the microstructure of the carbon cotton and carbon-cotton cathode. The carbon cotton is fabricated by carbonizing the cotton at 900 °C for 6 h with a heating rate of 2 °C min-1 under argon atmosphere. The carbon-cotton electrode (Fig. 1a) has a cross-linked spiral carbon-fiber network that is armored with microporous reaction sites, forming a hierarchical macro-/micro-porous architecture. The macroporous channels allow the carbon-cotton cathode to encapsulate a high amount of catholyte (Fig. 1b). The high-sulfur-loading carbon-cotton cathode is fabricated by impregnating the carbon cotton with a high amount of Li2S6 catholyte (80 µL). The cells have a fixed electrolyte-to-sulfur ratio of 6.8. The high tortuosity of the carbon-cotton cathode benefits the catholyte infiltration and the ensuing active-material retention. As a result, the carbon-cotton cathodes with the highest values of both sulfur loading (61.4 mg cm-2) and sulfur content (80 wt.%) demonstrate enhanced electrochemical utilization with the highest areal capacity (56 mA h cm-2), volumetric capacity (1,121 mA h cm-3), and gravimetric capacity (724 mA h g-1) simultaneously (Fig. 2a). On the other hand, the abundant microporous reaction sites (micropore surface area: 557 m2 g-1) spread throughout the carbon cotton enlarge the accessible reaction area among electrons, catholyte, and active material, facilitating the redox chemistry and guaranteeing the smooth operation of the high-loading/content Li-S system. Therefore, in Fig. 2, the high-loading carbon-cotton cathode exhibits (i) enhanced cycle stability with a good dynamic capacity retention of 70% after 100 cycles and (ii) improved cell-storage stability with a high static capacity retention of above 93% and a low time-dependent self-discharge rate of 0.12% per day after storing for a long period of 60 days. In conclusion, the electrochemical enhancements and engineering designs of the carbon-cotton cathodes make them advanced cathode architectures for the development of high-loading/content sulfur cathodes in high-energy-density Li–S batteries. REFERENCES 1. S. Urbonaite, T. Poux and P. Novák, Adv. Energy Mater., 5, 1500118 (2015). 2. A. Manthiram, S.-H. Chung and C. Zu, Adv. Mater., 27, 1980 (2015). 3. M. Hagen, D. Hanselmann, K. Ahlbrecht, R. Maça, D. Gerber, J. Tübke, J. Adv. Energy Mater., 5, 1401986 (2015). 4. S.-H. Chung, C.-H. Chang and A. Manthiram, ACS Nano, 10, 10462 (2016). Figure 1

Flexible Graphene-Based Composite Films for Supercapacitors with Tunable Areal Capacitance

Flexible supercapacitors based on paper-like electrodes have attracted significant interest because of the increasing demands in the energy storage, and they are recently claimed to be minimized and portable for meeting practical applications. As promising binder-free electrode materials in the supercapacitors, graphene-based films have been developed for enhancing their performance in energy storage by insetting “spacers” in-between nanosheets to prevent inevitable aggregations. In this study, a facile and versatile strategy is presented for fabricating graphene-based composite films by introducing activated carbonized cotton fibers to regulate the chemical composition, surface area and pore size distribution. The obtained composite films permit to present substantially increased energy storage capability (capacitance of 310Fg−1 and 150Fg−1 at 0.1Ag−1 and 10Ag−1 in 6molL−1 KOH electrolyte, respectively). Furthermore, tunable areal capacitance is realized by altering the stacked film layers without loss of mass specific capacitance. The devices based on composite films with excellent power density (up to 156.5mWcm−2) and energy density (240μWhcm−2) highlight a controllable, mini-sized and high-efficiency stage for energy storage. Such unique strategy suggests great potential in the commercialization of portable electronic devices, which require greater capacitance in a limited area.