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Polylactic acid (PLA), a biodegradable plastic, is used to substitute commercial plastics in various fields such as disposable packaging materials and mulching films. Although the biodegradation of PLA under submerged or composting conditions is accelerated, increasing the biodegradability of PLA under soil burial conditions is still a challenge. This study reviews and compares the PLA biodegradation ability of Bacillus amyloliquefaciens and Brevibacillus brevis, both PLA-degrading bacteria. The biodegradation ability of a single bacteria in non-composting conditions was evaluated. In addition, in terms of biostimulation, PLA biodegradation according to nitrogen sources was compared. As a result, a higher PLA biodegradation ability was found in B. brevis than in B. amyloliquefaciens. Moreover, it was confirmed that the biodegradation of the PLA film was increased by using soytone as a nitrogen source in both bacteria. Controlling the nitrogen source could be a new way to increase the biodegradation of PLA.

A solar-powered integrated supercapacitor (SPIS) with an inverted organic solar cell (iOSC) as the energy conversion unit and a supercapacitor (SC) as the energy-storage unit is a workable combinat...

Here we report gel polymer electrolytes (GPEs) formed by the film casting of the solution containing poly(ethylene glycol) methyl ether methacrylate (PEGMA) and trimethylolpropane ethoxylate triacrylate (ETPTA) with poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), followed by the thermal radical polymerization and liquid electrolyte absorption. The resulting GPEs show a semi-interpenetrating polymer network (SIPN) structure that provides film robustness which is investigated by morphological, structural, and electrochemical studies. Particularly, the GPE prepared by the composition of 98 mol% PEGMA and 2 mol% ETPTA in the presence of 40 wt% of PVDF-HFP (relative to total amount of PEGMA and ETPTA) manifests large ionic conductivity (1.46 × 10−3 S cm−1) and tensile strength (6.28 MPa at elongation at break of 156%) at a room temperature due to large uptake of the liquid electrolyte (up to 267%) and SIPN structure. We also verify that the GPE is electrochemically stable up to 4.7 V (vs. Li/L+), suggesting it holds the great promise of a polymer electrolyte membrane for energy storages such as rechargeable batteries or supercapacitors.

Laser-induced graphene (LIG) typically exhibits a mesostructure with a small specific surface area, which is detrimental to the electrochemical performance of micro-supercapacitors (MSCs). Herein, ...

Full utilization of electrodes toward high-performance energy storage is challenging in cases where electrode/electrolyte interface is significant. From a practical perspective, this is particularly important in cases where a thick electrode or one with a high mass loading is needed. Here, we report an approach to increase the electrode performance by the infilling of a highly ion-conductive organic gel polymer electrolyte (EI-GPE, ionic conductivity ∼9.2 mS cm−1) into a multi-walled carbon nanotube (MWCNT) electrode with high mass loadings of up to 26 mg cm−2 (or significant thicknesses of up to 443 μm). Typical GPE (t-GPE) with a film-forming property but moderate ionic conductivity (1.2 mS cm−1) is then placed over the EI-GPE-filled electrode surface, resulted in flexible supercapacitor. Infilling of EI-GPE into MWCNT electrode provides a large-ion accessible interface that affords the increase in volumetric capacitance and energy density, about sixfold greater than that of the typical supercapacitors configured by sandwiching t-GPE as both electrolyte and the separator between a pair of electrodes. Importantly, this method enables scaling of the areal capacitance with electrode thickness (or mass loading of active material). A pouch type EI-SC provides stable performance after bending, suggesting it holds the promise of flexible energy storage.

This paper describes a facile method for fabricating polyaniline (PANI) films with well-defined three-dimensional (3D) porous networks and improved electrochemical activity. The PANI hydrogel pastes with different compositions are directly cast into thin films by the doctor blade technique. After a dehydration step, the conductivity of the PANI drastically increases, while the porous structure with hierarchical macro- and meso-porosity is formed in the PANI film. The electrical conductivity tends to increase with the thickness of the porous PANI film until it fails to form a mechanically stable film not exhibiting cracking problems. We found that the amount of the initiator, the aniline monomer, and the crosslinker significantly affect not only the micro-morphology of PANI films, but also their electrical and electrochemical characteristics. Importantly, when the amounts of the crosslinker and the initiator increase, the polymer film forms with a dense internal morphology with smaller pores. Based on the engineered synthesis composition, we demonstrate a supercapacitor with porous PANI electrodes. Due to the hierarchical porous structure, large surface area and the improved conductivity, the resulting devices show excellent volumetric capacitances, which are comparable to or much higher than those previously reported.

The electrical conductivity and mechanical strength of fibers constructed from single-walled carbon nanotubes (CNTs) are usually limited by the weak interactions between individual CNTs. In this work, we report a significant enhancement of both of these properties through chemical cross-linking of individual CNTs. The CNT fibers are made by wet-spinning a CNT solution that contains 1,3,5-tris(2'-bromophenyl)benzene (2TBB) molecules as the cross-linking agent, and the cross-linking is subsequently driven by Joule heating. Cross-linking with 2TBB increases the conductivity of the CNT fibers by a factor of ∼100 and increases the tensile strength on average by 47%; in contrast, the tensile strength of CNT fibers fabricated without 2TBB decreases after the same Joule heating process. Symmetrical supercapacitors made from the 2TBB-treated CNT fibers exhibit a remarkably high volumetric energy density of ∼4.5 mWh cm

Herein, we introduce for the first time that Cs2CO3 can work with SnO2 based on a facile low-temperature solution-processed as dual electron transport layers (ETL) for enhancing device performance of inverted organic solar cells (iOSCs). Aside from better morphologies, a lower work function of ETLs, and an efficient charge extraction, along with a much lower transport resistance at the interfaces are found for iOSCs using SnO2/Cs2CO3 rather than devices based on the SnO2 only. The iOSC devices with P3HT:PC60BM as an active layer, using SnO2/Cs2CO3 (0.5 mg/ml) as dual ETLs, achieved a champion power conversion efficiency (PCE) of 3.75%, which is >36% higher than that of only the based SnO2 (2.75%). Moreover, their PCEs remained at ∼94% of the initial values after storage for 4 weeks in ambient air without any encapsulations, thus demonstrating the excellent long-term device stability. Notably, for the PTB7-Th:PC70BM systems, we also achieved an impressive champion PCE of 7.78% with using SnO2/Cs2CO3 (0.5 mg/ml) as dual ETLs, meanwhile devices based on SnO2 only exhibited a humble PCE of 4.08%. We believe that SnO2/Cs2CO3 dual ETLs concept can also be applied to other optoelectronic devices such as perovskite solar cells or light-emitting diodes, where an ETL is required to ensure high efficiency.

In this work, we present the nanohybrid electrode (termed as p-h-SnO2/GA) of porous hollow SnO2 (p-h-SnO2) integrated on the surface of graphene aerogel (GA) for anodes with large lithium storage capacity. Selective etching of Ni from Ni3Sn2 nanoparticles produces the porous hollow nanostructure of SnO2, which is important for providing the structural flexibility that can accommodate the volume change of SnO2 during the lithiation and delithiation processes. GA also serves as a buffer for the volume change of SnO2 and induces effective charge transports through its interconnected porous network structure. These combined advantages of p-h-SnO2 and GA enable a reversible Li storage capacity as high as 620 mAh g−1 with ∼100% Coulombic efficiency at a specific current of 50 mA g−1 over 200 charge–discharge cycles and ∼71% of rate-retention capability over the specific currents of 100 mA g−1–1 A g−1. It makes this nanohybrid electrodes an attractive candidate for high-performance lithium ion battery anode.

A simple, green approach to recover NiMnCoC

Flexible nanohybrid paper electrode (termed as C-I) consisting of multi-walled carbon nanotubes (MWCNTs) and indium sulfide (In2S3) nanoplates is formed via a simple vacuum-assisted assembly and used as an anode for sodium-ion batteries (SIBs). In2S3 nanoplates which are well distributed on and bound to the MWCNTs provide a high Na storage capacity of the nanohybrid electrode as high as 410 mAh g−1 at a specific current of 50 mA g−1 over 100 charge/discharge cycles and ∼97% of rate-retention capability over the specific currents of 50 mA g−1 to 1 A g−1 for at least 50 charge/discharge cycles. Particularly, when In2S3 in the form of nanoplates was added to MWCNTs, the electrochemical performances are considerable as compared to those of bulk In2S3 or MWCNTs film electrodes. This highlights the importance of nanohybrid approach in overcoming the intrinsic complication of In2S3, i.e., the agglomeration of In2S3 into bulk form during assembly, followed by annealing. For C-I nanohybrid electrode, capacitive contribution (∼95%) rather than insertion contribution (∼5%) is predominant during charge/discharge process. The nanohybrid paper electrode is robust and thus retains capacity even under repeated mechanical deformation (flat-bent-flat cycles), demonstrating the potential of the electrode being used for flexible and wearable energy storage.

A simple, green approach to recover NiMnCoC2O4 as an electrode material for high-performance pseudocapacitors from spent LiNiMnCoO2 (NMC) batteries is proposed. Four strategic metals (Li, Ni, Co, and Mn) were leached from spent NMC batteries using several organic acids as model green leachants. Among the various candidates of green leaching agents, 2 M citric acid and 5 wt% glucose were selected as the leachant and reductant, respectively. Microwave irradiation was conducted during the leaching step to maximize the performance of the leaching rate and efficiency. The leaching efficiencies within 0.5 h for Ni(II), Li(I), Mn(II), and Co(II) were 90.7 ± 1.6%, 98.3 ± 2.4%, 94.9 ± 4.3%, and 95.6 ± 1.4%, respectively, and were thus as efficient as using aqua regia leaching. After the leaching process, divalent metal ions, that is, Ni(II), Co(II), and Mn(II), were immediately separated at room temperature using oxalic acid. The recovered samples were not further treated and used directly for energy storage applications. The recovered NiMnCoC2O4⋅nH2O has been demonstrated as a promising electrode for pseudocapacitors, providing a specific capacitance of 1641 F/g, good rate-retention capability (80% of low-current capacitance), and good cycle stability over 4000 charge–discharge cycles.

Correction for ‘Optical humidity sensors based on lead-free Cu-based perovskite nanomaterials’ by Hoseok Lee et al., Nanoscale Adv., 2022, 4, 3309–3317, https://doi.org/10.1039/D2NA00168C.

This work reports the thinnest and smallest hollow N-doped carbon boxes among recently reported hollow N-doped carbon materials. Hollow and N-rich microporous organic networks (H-NMONs) were prepared by the azide–alkyne Huisgen cycloaddition of tetra(4-ethynylphenyl)methane and 1,4-diazidobenzene on the surface of Cu2O nanocubes and the successive acid etching of inner Cu2O. The Cu2O nanocubes played roles of templates and networking catalysts. The networking reaction generated N-rich triazole rings in the MON. Heat treatment of H-NMONs under argon resulted in the formation of hollow N-doped carbon boxes (H-NCBs). The diameter and shell thickness of H-NCBs were 130 and 12 nm, respectively. The H-NCBs showed superior electrochemical performance in H2SO4 electrolyte as energy storage materials for supercapacitors, compared with that in KOH electrolyte. Among the H-NCBs, H-NCB-900 which was obtained by the heat treatment of H-NMON at 900 °C showed the best performance with capacitances of 286 and 251 F/g at ...

The growing demands of next-generation applications for high power and energy sources necessitate advances in hierarchically porous carbon-based energy storage materials, which improve the overall kinetics of electrolytic reactions by providing efficient ion and electron transport pathways and facilitate electrolyte infiltration into the electrode during charging/discharging. Herein, we fabricate hierarchically structured porous carbon electrodes (cNPIM), prepared by solution casting of a polymer of intrinsic microporosity (PIM-1) followed by nonsolvent-induced phase separation and carbonization. The obtained material exhibits a considerable surface area (∼2100 m2 g−1), high electrical conductivity (150 S cm−1), high specific capacitances (345, 235, and 195 F g−1 in three-, two-electrode aqueous systems, and two-electrode organic systems, respectively) at 1 A g−1, and an exceptional specific energy of 43.2 W h kg−1 at a specific power of 1.25 kW kg−1, featuring a pore size gradient in the surface normal direction.

Bio-inspired and environmentally friendly chemical functionalization is a successful way to a new class of hybrid electrode materials for applications in energy storage. Quinone (Q)-hydroquinone (QH 2 ) couples, a prototypical example of organic redox systems, provide fast and reversible proton-coupled electron-transfer reactions which lead to increased capacity. To achieve high capacitance and rate performance, constructing three-dimensional (3D) continuous porous structure is highly desirable. Here we report the hybrid electrodes (GA-C) consisting of 3D graphene aerogel (GA) functionalized with organic redox-active material, catechol derivative, for application to high-performance supercapacitors. The catechol derivative is adsorbed on the surface of GA through non-covalent interactions and promotes fast and reversible Q/QH 2 faradaic reactions, providing large specific capacitance of 188 F g −1 at a current of 1 A g −1 and a specific energy of ∼25 Wh kg −1 at a specific power of ∼18,000 W kg −1 . 3D continuous porous structure of GA electrode facilitates ion and electron transports, resulting in high rate performance (∼140 F g −1 at a current of 10 A g −1 ).

Li-iodine chemistry is of interest for electrochemical energy storage because it has been shown to provide both high power and high energy density. However, Li-iodine batteries are typically formed using Li metal and elemental iodine, which presents safety and fabrication challenges (e.g., the high vapor pressure of iodine). These disadvantages could be circumvented by using LiI as a starting cathode. Here, we present fabrication of a reduced graphene oxide (rGO)/LiI composite cathode, enabling for the first time the use of LiI as the Li-ion battery cathode. LiI was coated on rGO by infiltration of an ethanolic solution of LiI into a compressed rGO aerogel followed by drying. The free-standing rGO/LiI electrodes show stable long-term cycling and good rate performance with high specific capacity (200 mAh g–1 at 0.5 C after 100 cycles) and small hysteresis (0.056 V at 1 C). Shuttling was suppressed significantly. We speculate the improved electrochemical performance is due to strong interactions between the...

A series of pore-filling membranes are prepared by impregnating porous cross-linked benzoxazine-benzimidazole copolymer P( p BUa- co -BI) substrates with sulfonated poly(arylene ether sulfone)s (SPAES)s having different degree of sulfonation for polymer electrolyte membrane fuel cells operating at high-temperatures (>100 °C) and low-humidity ( p BUa- co -BI) substrates are prepared by extracting dibutyl phthalate (DBP) included in P( p BUa- co -BI) films using methanol. The P( p BUa- co -BI) films are prepared by stepwise heating the casted N,N- dimethylacetamide solution containing the mixtures of poly[2,2′-( m -phenylene)-5,5′-bibenzimidazole] (PBI), 3-phenyl-3,4- dihydro-6- tert -butyl-2 H -1,3-benzoxazine ( p BUa), and DBP to 220 °C. The pore-filling membranes are found to have much improved dimensional stability and mechanical strength compared with the SPAES membranes. Although the proton conductivity values of the pore-filling membranes are slightly smaller than those of the SPAES membrane, their cell performance is superior to that of the SPAES membrane at 120 °C and 40% RH conditions because ultrathin pore-filling membranes (15–20 µm) having high mechanical strength can be prepared and they can contain a larger content of chemically-bound water.

Proton conductive porous substrates consisting of cross-linked benzoxazine-benzimidazole copolymers are developed for practical application of reinforced pore-filling membranes in polymer electrolyte membrane fuel cells operating at high-temperatures (>100 °C) and low relative humidity (

Fiber electrodes provide interesting opportunities for energy storage by providing both mechanical flexibility and the opportunity to impart multifunctionality to fabrics. We show here carbon nanotube (CNT)-embedded agarose gel composite fiber electrodes, with a diameter of ∼120 μm, consisting of 60 wt % CNTs that can serve as the basis for flexible and wearable fiber microsupercapacitors (mSCs). Via an extrusion process, CNT bundles are induced to align in an agarose filament matrix. Due to the shear alignment of the CNT bundles, the dehydrated filaments have an electrical conductivity as high as 8.3 S cm–1. The composite fiber electrodes are mechanically stable, enabling formation of twisted two-ply fiber mSCs integrated with a solid electrolyte. The fiber mSC shows a high capacitance (∼1.2 F cm–3), good rate retention (∼90%) at discharge current densities ranging from 5.1 to 38 mA cm–3, long cycle life under repeated charging/discharging (10% fade after 10 000 cycles) and good performance after at leas...

Tin oxide (SnO2) has been widely accepted as an effective electron transport layer (ETL) for optoelectronic devices because of its outstanding electro-optical properties such as its suitable band energy levels, high electron mobility, and high transparency. Here, we report a simple but effective interfacial engineering strategy to achieve highly efficient and stable inverted organic solar cells (iOSCs) via a low-temperature solution process and an SnO2 ETL modified by zwitterion nondetergent sulfobetaine 3-(4-tert-butyl-1-pyridinio)-1-propanesulfonate (NDSB-256-4T). We found that NDSB-256-4T helps reduce the work function of SnO2, resulting in more efficient electron extraction and transport to the cathode of iOSCs. NDSB-256-4T also passivates the defects in SnO2, which serves as recombination centers that greatly reduce the device performance of iOSCs. In addition, NDSB-256-4T provides the better interfacial contact between SnO2 and the active layer. Thus, a higher power conversion efficiency (PCE) and longer device stability of iOSCs are expected for a combination of SnO2 and NDSB-256-4T than for devices based on SnO2 only. With these enhanced interfacial properties, P3HT:PC60BM-based iOSCs using SnO2/NDSB-256-4T (0.2 mg/mL) as an ETL showed both a higher average PCE of 3.72%, which is 33% higher than devices using SnO2 only (2.79%) and excellent device stability (over 90% of the initial PCE remained after storing 5 weeks in ambient air without encapsulation). In an extended application of the PTB7-Th:PC70BM systems, we achieved an impressive average PCE of 8.22% with SnO2/NDSB-256-4T (0.2 mg/mL) as the ETL, while devices based on SnO2 exhibited an average PCE of only 4.45%. Thus, the use of zwitterion to modify SnO2 ETL is a promising way to obtain both highly efficient and stable iOSCs.

Pure silica zeolite (Silicalite-1) bricks with a 2D morphology were assembled on a slide glass and used as templates for the preparation of microstructured organic network films (MONFs) with a hollow space and holes by the Sonogashira coupling of tetrakis(4-ethynylphenyl)methane and 1,4-diiodobenzene and silica etching. The MONFs were adhesive to polyethylene terephthalate (PET) films due to their unique structural effects. Cu was loaded on the MONF/PET by electroless deposition. The Cu/MONF/PET showed excellent retention of conductivities in repeated severe bending.

Herein, we report integrated photo-rechargeable supercapacitors (IPSs) composed of the inverted organic solar cell (iOSC) and solid-state supercapacitor (SC), enabling a high-performance self-power pack. The iOSC serves as a self-power source while the SC functions as energy storage, and both share an indium-tin-oxide (ITO) electrode that affords improved charge propagation across the devices. Combining the energy harvesting and storage devices in this way significantly alleviates the limitations of each device. The power fluctuation of the iOSC can be reimbursed by the SC, thus allowing for a stable energy output. Moreover, the SC is frequently charged by the iOSC during the daytime, thereby greatly reducing the charging time and avoiding a complete discharge as well. When the SC of the IPS is charged by the iOSC under AM 1.5 G of illumination, the overall energy conversion-storage efficiency is ca. 2.27%. Our work provides an effective strategy for further study to fabricate a small, lightweight, portable/wearable self-power pack by integrating energy harvesting and energy storage devices into a single structure.

The electrodes of a hybrid electrochemical capacitor which utilize the quinone (Q)-hydroquinone (QH2) couple, a prototypical organic redox system known to provide fast and reversible proton-coupled electron-transfer reactions, are deterministically mesostructured via a colloidal templating strategy to provide good ion and electron transport pathways, enabling a high rate performance. Specifically, a conducting polymer, polypyrrole (PPy), is functionalized with a pseudocapacitive material, a Q/QH2-containing catechol derivative, by noncovalent interactions. The mesostructure of this hybrid material is formed into an ordered 3D porous structure by a polystyrene colloidal crystal template-assisted electrosynthesis. The catechol derivative is sufficiently bound to the PPy through noncovalent interactions to provide a volumetric capacitance as high as ≈130 F cm−3 and a capacitance retention of ≈75% over 10 000 charging/discharging cycles. When compared with a randomly structured electrode, the deterministically structured electrode exhibits an improved rate performance due to the mesostructure facilitated electron and ion transport.

Sulfonated poly(arylene ether sulfone) (SPAES) based composite membranes were prepared with core–shell silica particles having poly(4-styrenesulfonic acid) and poly(4-vinylpyridine) in shell layers named S–Si and P–Si, respectively, to investigate the effect of acidic and basic silica fillers on membrane properties. The core–shell silica particles were obtained by hydrolysis of vinyltrimethoxysilane followed by radical polymerization of vinyl monomers (4-styrenesulfonic acid sodium salt and 4-vinylpyridine) on the silica particle with vinyl groups. Incorporation of S–Si and P–Si into SPAES increased dimensional stability, mechanical strength, and proton conductivity of the membranes. In particular, P–Si was found to be more effective filler materials to improve these properties by additional well-connected hydrophilic channels having sulfonate/pyridinium structures formed around the silica particles through the acid–base interaction between the pyridine groups of the P4VP shell and the sulfonic acid groups of SPAES.

The reliability and durability of energy storage devices are as important as their essential characteristics (e.g., energy and power density) for stable power output and long lifespan and thus much more crucial under harsh conditions. However, energy storage under extreme conditions is still a big challenge because of unavoidable performance decays and the inevitable damage of components. Here, we report high-temperature operating, flexible supercapacitors (f-SCs) that can provide reliable power output and extreme durability under severe electrochemical, mechanical, and thermal conditions. The outstanding capacitive features (e.g., ∼40% enhancement of the rate capability and a maximum capacitances of 170 F g(-1) and 18.7 mF cm(-2) at 160 °C) are attributed to facilitated ion transport at elevated temperatures. Under high-temperature operation and/or a flexibility test in both static and dynamic modes at elevated temperatures100 °C, the f-SCs showed extreme long-term stability of 100000 cycles (93% of initial capacitance value) and mechanical durability after hundreds of bending cycles (at bend angles of 60-180°). Even at 120 °C, the versatile design of tandem serial and parallel f-SCs was demonstrated to provide both desirable energy and power requirements at high temperatures.

Sulfonated poly(arylene ether sulfone) membranes with cross-linked structures (C-SPAES) were simply prepared by simultaneously casting and heating the polymer solutions composed of sulfonated poly(arylene ether sulfone) with azidomethyl side groups (SPAES-N3), cross-linkers such as 1,4-diethynylbenzene and 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt tetrahydrate, and a click reaction catalyst such as CuBr and N,N,N′,N″,N″-pentamethyldiethylenetriamine in N,N-dimethylacetamide, where SPAES-N3 were prepared by the substitution of sulfonated PAES (SPAES) through chloromethylation followed by azidation reaction. C-SPAES membranes obtained using the optimum amount of the cross-linkers showed much improved chemical and physical stabilities and mechanical strength compared with linear SPAES membrane. Since the cross-linked structures were formed by the cross-linker having sulfonic acid groups, C-SPAES membranes showed higher ion exchange capacity and proton conductivity than the linear SPAES membrane...

Nanoscale interfaces can modify the phase transition behaviors of polymeric materials. Here, we report the double glass transition temperature (Tg) behavior of sulfonated polystyrene (sPS) by the inclusion of 14 nm amine-functionalized silica (NH2-SiO2) nanoparticles, which is different from the single Tg behaviors of neat sPS and silica (SiO2)-filled sPS. The inclusion of 20 wt% NH2-SiO2 nanoparticles results in an increase of Tg by 9.3 °C as well as revealing a second Tg reduced by 44.7 °C compared to the Tg of neat sPS. By contrast, when SiO2 nanoparticles with an identical concentration and size to NH2-SiO2 are dispersed, sPS composites possess a single Tg of 7.3 °C higher than that of the neat sPS. While a nanoscale dispersion is observed for SiO2 nanoparticles, as confirmed by microscopic and X-ray scattering analyses, NH2-SiO2 nanoparticles show the coexistence of micron-scale clustering along with a nanoscale dispersion of the individual nanoparticles. The micro-phase separation contributes to the free volume induced Tg reduction by the plasticization effect, whereas the Tg increase originates from the polymer segment mobility constrained by nanoconfinement and the rigid amorphous fractions deriving from strong polymer-particle interactions.

Sulfonated poly(arylene ether sulfone) (SPAES) composite membranes were prepared using thermally-treated graphene oxide (GO) and poly(2,5-benzimidazole)-grafted graphene oxide (ABPBI-GO) as fillers for proton exchange membrane fuel cell (PEMFC) applications. Pristine graphene oxide was obtained from graphite by chemical oxidation, and 3,4-diaminobenzoic acid was then reacted with pristine graphene oxide to obtain ABPBI-GO. When GO and ABPBI-GO were incorporated into the SPAES matrix, the dimensional stability and mechanical strength of the membrane were improved. In particular, the SPAES/ABPBI-GO composite membranes exhibited improved dimensional stability, larger Young's modulus, and larger elongation at break than the SPAES/GO composite membranes due to the acid–base interaction between the sulfonic acid group of the SPAES matrix and the basic imidazole unit of ABPBI-GO. In addition, the SPAES/ABPBI-GO composite membranes possessed higher proton conductivity than pristine SPAES and SPAES/GO composite membranes because the acid–base interaction can generate additional proton conduction pathways in the membrane structures.

We report in-situ synthesis and direct deposition of Fe 2 O 3 nanoparticles (NPs) on the ionic liquid (IL)-functionalized carbon nanotubes (fCNT). As shown in transmission electron microscope (TEM) and scanning TEM (STEM) images, Fe 2 O 3 NPs with the diameter of 3–5 nm are randomly distributed on the sidewall of fCNT, revealing the nanocrystalline structure. The chemical identity and interaction of the fCNT/Fe 2 O 3 composite are investigated by FT-IR, Raman and XPS analyses. In particular, the fCNT/Fe 2 O 3 composite is solution-processable in a form of binder free and self-standing film. Such a free-standing electrode film based on the fCNT/Fe 2 O 3 composite achieve the discharge capacity of 413 mAh g −1 which is much greater than 34 mAh g −1 of the CNT and 191 mAh g −1 of the fCNT due to the redox reaction of Fe 2 O 3 NPs. Moreover, the fCNT/Fe 2 O 3 composite show the coulombic efficiency of 98% and the capacity fading from 272 mAh g −1 to 182 mAh g −1 after 50 cycles of charge/discharge.

Based on reversible photo crosslinkable properties, a series of polymethacrylate derivatives having cinnamoyl group in the side chain has been designed and synthesized. By simple UV irradiation and thermal treatment on these polymer films, a complete healing behavior accompanied by changes of the surface hardness was observed.

Here we report a nanohybrid of reduced graphene oxide (rGO) nanosheets at which monodispersed starburst carbon spheres (MSCSs) are intercalated for the use in high-performance supercapacitor electrodes. MSCSs that have large electrolyte ions-accessible surface area enlarge the interspacing between rGO nanosheets as a result of intercalation so that a hybrid electrode can increasingly form electrical double layers that store energy. Such electrode organization provides facilitated transport paths for both electron and ion. The volumetric capacitance of the hybrid electrode is 25 F cm−3 that is obtained at a constant current of 0.073 A cm−3, at least 2.5-fold greater than that of rGO electrode. The hybrid electrode also shows a good rate-retention capability of 81% as specific currents change from 0.073 to 1.5 A cm−3. The initial capacitance of the hybrid electrode remains unchanged, nearly 100% for at least 5000 charge/discharge cycles. The electrode also delivers high energy density, 1.7 × 10−3 Wh cm−3, and power density, 2.7 W cm−3.

Strong demand for high-performance energy-storage devices has currently motivated the development of emerging capacitive materials that can resolve their critical challenge (i.e., low energy density) and that are renewable and inexpensive energy-storage materials from both environmental and economic viewpoints. Herein, the pseudocapacitive behavior of lignin nanocrystals confined on reduced graphene oxides (RGOs) used for renewable energy-storage materials is demonstrated. The excellent capacitive characteristics of the renewable hybrid electrodes were achieved by synergizing the fast and reversible redox charge transfer of surface-confined quinone and the interplay with electron-conducting RGOs. Accordingly, pseudocapacitors with remarkable rate and cyclic performances (~96 % retention after 3000 cycles) showed a maximum capacitance of 432 F g(-1), which was close to the theoretical capacitance of 482 F g(-1) and sixfold higher than that of RGO (93 F g(-1)). The chemical strategy delineated herein paves the way to develop advanced renewable electrodes for energy-storage applications and understand the redox chemistry of electroactive biomaterials.

Graphene based electrical conductors are under consideration for numerous applications in energy storage, energy conversion devices, electronics and sensors. Here, we report a facile and versatile method for fabrication of graphene based composite microwires ranging from ∼20 to 250 μm in diameter via size reduction during dehydration of extruded larger diameter graphene oxide-loaded agarose hydrogel fibers. The graphene oxide is effectively reduced to graphene by chemical and thermal treatment. After dehydration and reduction, the resulting graphene composite microwires exhibit high electrical conductivities of up to 1.8 S m−1.

Submicron-thick films of composite (CSN) electrodes were prepared by the simple spin-coating of a multiwalled carbon nanotube (MWCNT) suspension with sucrose as the precursor to form a thin carbon layer; this was followed by heat treatment at 1000 °C for 2 h. Thin carbon layers were coated onto the outer surface of the MWCNTs and the resulting CSN electrode was shown to be an interconnected open network structure. This binder-free thin-film CSN electrode with a unique architecture has a large areal capacitance of ∼723 μF cm−2 at a constant current of 0.23 μA cm−2 in a Na2SO4 aqueous electrolyte. About 81% of the initial capacitance is preserved, even at high specific currents. Based on the results of electrochemical impedance spectroscopy, the CSN electrode was shown to concurrently optimize ion and electron transport for high power delivery. It also shows good cycle stability after prolonged operation (up to 3000 charge/discharge cycles).