Search

Lithium is perceived as an ideal anode for next generation batteries with high‐energy density. However, the critical issue of the intractable growth of Li dendrites, which leads to a poor cycling life, still remains. Herein, a hierarchical surface is designed and constructed on carbon fiber (CF) using binders in fabricated CF paper (CFP). The lightweight CF with high mechanical properties is facilitated to establish a 3D network structure as an alternative to Cu foil. The binders are transformed into oxygen‐containing amorphous carbon and sodium carbonate (Na2CO3) using a low‐temperature carbonization process, leading to uniform Li nucleation and a stable solid electrolyte interphase layer with inorganic components. In the electrochemical test, the CFP with amorphous carbon and Na2CO3 (ANCFP) shows a low Li nucleation overpotential and smooth dendrite‐free Li plating. Furthermore, the ANCFP electrode exhibits good cycling stability in half and symmetrical cells. A full‐cell assembled using a LiFePO4 cathode with high loading (≈13 mg cm−2) achieves a high‐energy density of 428 Wh kg−1 (at 0.1 C) and an excellent capacity retention of 85% at 1 C after 300 cycles. This strategy is expected to help realize highly stable Li metal anodes for practical application by suppressing Li dendrite growth. [ABSTRACT FROM AUTHOR]

With the emergence of disposable electronics, compatible safe, flexible, and recyclable power sources have become a critical challenge. Here, an ultra‐thin paper‐based iontronic power source is enabled by highly efficient translational Li+ transport within 2D nanofluidic channels of graphene oxide under a salinity gradient and the fine‐tuned interfacial redox reactions. The paper‐based source can generate volumetric power and energy densities of 438.02 mW cm−3 and 30.02 mWh cm−3, respectively. Its areal power density is 1095.05 mW cm−2, surpassing most flexible batteries. It maintains a working state when bent or even cut and can be simply recycled by incineration. By filling 2D nanofluidic inks in different pens, the power source can be drawn on paper when needed, which not only overcomes the inherent defect of self‐discharge for most batteries but also enables writing directly on any insulating substrates. Furthermore, all‐in‐one disposable electronics comprised of an energy management system (paper‐based triboelectric nanogenerator and iontronic power source) and wireless sensing system (temperature sensor with NFC circuits) are integrated onto one piece of paper by duplex printing, demonstrating the huge potential of such integratable iontronic power sources for soft, wireless, and conformable disposable electronics. [ABSTRACT FROM AUTHOR]

Abstract: In response to the demand for flexible and sustainable energy storage devices that exhibit high electrochemical performance, a supercapacitor system is fabricated using mulberry tree‐derived paper as a substrate and Poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) and carbon black as the active material. The mulberry paper‐based supercapacitor system demonstrates high energy density of 29.8–39.8 Wh kg−1 and power density of 2.8–13.9 kW kg−1 with 90.7% retention of its initial capacity over 15 000 charge–discharge cycles. In addition, the mulberry tree fibers are known to have superior mechanical strength and toughness and the mulberry paper‐based supercapacitor; as a result, exhibit high mechanical and chemical toughness; 99% of its initial capacity is retained after 100 repeated applications of bending strains, and twisting. 94% capacity retention is observed even after exposure to HCl and H2SO4 acid solutions. The fabrication methodology of the mulberry‐based supercapacitor is highly scalable and could be stacked to increase the energy storage capacity, where operation of light‐emitting diode lights with a drive voltage of 12 V integrated in a wearable device is demonstrated. [ABSTRACT FROM AUTHOR]

In response to the demand for flexible and sustainable energy storage devices that exhibit high electrochemical performance, a supercapacitor system is fabricated using mulberry tree-derived paper as a substrate and Poly(3,4- ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and carbon black as the active material. The mulberry paper-based supercapacitor system demonstrates high energy density of 29.8-39.8 Wh kg-1 and power density of 2.8-13.9 kW kg-1 with 90.7% retention of its initial capacity over 15 000 charge-discharge cycles. In addition, the mulberry tree fibers are known to have superior mechanical strength and toughness and the mulberry paper-based supercapacitor; as a result, exhibit high mechanical and chemical toughness; 99% of its initial capacity is retained after 100 repeated applications of bending strains, and twisting. 94% capacity retention is observed even after exposure to HCl and H2SO4 acid solutions. The fabrication methodology of the mulberry-based supercapacitor is highly scalable and could be stacked to increase the energy storage capacity, where operation of light-emitting diode lights with a drive voltage of 12 V integrated in a wearable device is demonstrated. [ABSTRACT FROM AUTHOR]

A simple and scalable direct laser machining process to fabricate MXene-on-paper coplanar microsupercapacitors is reported. Commercially available printing paper is employed as a platform in order to coat either hydrofluoric acid-etched or clay-like 2D Ti3C2 MXene sheets, followed by laser machining to fabricate thick-film MXene coplanar electrodes over a large area. The size, morphology, and conductivity of the 2D MXene sheets are found to strongly affect the electrochemical performance due to the efficiency of the ion-electron kinetics within the layered MXene sheets. The areal performance metrics of Ti3C2 MXene-on-paper microsupercapacitors show very competitive power-energy densities, comparable to the reported state-of-the-art paper-based microsupercapacitors. Various device architectures are fabricated using the MXene-on-paper electrodes and successfully demonstrated as a micropower source for light emitting diodes. The MXene-on-paper electrodes show promise for flexible on-paper energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract: A simple and scalable method to fabricate a yarn‐type supercapacitor with a large specific capacitance without the aid of traditional pseudocapacitive electrode materials such as conducting polymers and metal oxides is reported. The yarn‐type supercapacitors are made from twisting reduced graphene oxide (rGO) or/and single‐walled carbon nanotubes (SWNTs)‐coated Korean traditional paper (KTP). The yarn‐type paper supercapacitor displays surprisingly enhanced electrochemical capacitance values, showing synergistic effect between rGO and SWNTs (500 times larger than performance of yarn‐type rGO‐coated paper supercapacitors). Coating rGO or/and SWNTs on KTP gives good morphology to the composite film, in which porosity increases and mean pore diameter decreases. The yarn‐type rGO/SWNT paper supercapacitor shows good mechanical strength, high flexibility, excellent electrochemical performance, and long‐life operation. The yarn‐type supercapacitor has an excellent electrochemical performance with a specific capacitance of 366 F g−1 at scan rate of 25 mV s−1 and high stability without any degradation in electrical performance up to 10 000 charge–discharge cycles. The average capacitance of rGO/SWNT@KTP yarn‐type supercapacitors is seven times higher than that of sheet‐type supercapacitors at scan rate of 500 mV s−1. The lighting of a red light‐emitting diode (LED) is demonstrated by the yarn‐type paper supercapacitor without connecting supercapacitors in series. [ABSTRACT FROM AUTHOR]

The development of sodium-ion batteries for large-scale applications requires the synthesis of electrode materials with high capacity, high initial Coulombic efficiency (ICE), high rate performance, long cycle life, and low cost. A rational design of freestanding anode materials is reported for sodium-ion batteries, consisting of molybdenum disulfide (MoS2) nanosheets aligned vertically on carbon paper derived from paper towel. The hierarchical structure enables sufficient electrode/electrolyte interaction and fast electron transportation. Meanwhile, the unique architecture can minimize the excessive interface between carbon and electrolyte, enabling high ICE. The as-prepared MoS2@carbon paper composites as freestanding electrodes for sodium-ion batteries can liberate the traditional electrode manufacturing procedure, thereby reducing the cost of sodium-ion batteries. The freestanding MoS2@carbon paper electrode exhibits a high reversible capacity, high ICE, good cycling performance, and excellent rate capability. By exploiting in situ Raman spectroscopy, the reversibility of the phase transition from 2H-MoS2 to 1T-MoS2 is observed during the sodium-ion intercalation/deintercalation process. This work is expected to inspire the development of advanced electrode materials for high-performance sodium-ion batteries. [ABSTRACT FROM AUTHOR]

An efficient water splitting electrocatalyst is presented. Cheap and sustainable cellulose filter paper, infiltrated with nickel acetate as the nickel source, and phenanthroline as a ligand and nitrogen source are carbonized together. Nitrogen functionalities turn out to be crucial coordination sites for the supported Ni/NiO(OH) particles. This simple and scalable one step procedure leads to powders, but also to complete membranes made of ≈10 wt% Ni, supported on nitrogen functionalized carbon. The non-noble catalyst shows a low onset potential (330 mV vs reversible hydrogen electrode), high current density (e.g., j > 25 mA cm−­2 at η = 430 mV), excellent kinetics (Tafel slope of 44 mV dec−1), and a very favorable stability (<5% decay after 10 h electrolysis) in the oxygen evolution. The performance is similar or even better compared to state-of-the-art noble metal catalysts (e.g., IrO2, Ir/C, Ru/C, and Pt/C). Because of the simple, cheap, and scalable preparation procedure the catalyst is highly promising for practical low price/tech applications. Interestingly, the system is also active in the hydrogen evolution reaction, leading to a promising bifunctional catalyst. The benchmark characteristics are η10 = 390 mV for oxygen evolution and η10 = 190 mV for hydrogen evolution, that is, an overall efficiency of 68% at 10 mA current density. [ABSTRACT FROM AUTHOR]

Abstract: This study proposes a conformal surface coating of conducting polymer for protecting 1D nanostructured electrode material, thereby enabling a free‐standing electrode without binder for sodium ion batteries. Here, polypyrrole (PPy), which is one of the representative conducting polymers, encapsulated cobalt phosphide (CoP) nanowires (NWs) grown on carbon paper (CP), finally realizes 1D core–shell CoP@PPy NWs/CP. The CoP core is connected to the PPy shell via strong chemical bonding, which can maintain a Co–PPy framework during charge/discharge. It also possesses bifunctional features that enhances the charge transfer and buffers the volume expansion. Consequently, 1D core–shell CoP@PPy NWs/CP demonstrates superb electrochemical performance, delivering a high areal capacity of 0.521 mA h cm−2 at 0.15 mA cm−2 after 100 cycles, and 0.443 mA h cm−2 at 1.5 mA cm−2 even after 1000 cycles. Even at a high current density of 3 mA cm−2, a significant areal discharge capacity reaching 0.285 mA h cm−2 is still maintained. The outstanding performance of the CoP@PPy NWs/CP free‐standing anode provides not only a novel insight into the modulated volume expansion of anode materials but also one of the most effective strategies for binder‐free and free‐standing electrodes with decent mechanical endurance for future secondary batteries. [ABSTRACT FROM AUTHOR]

Abstract: Photocatalytic reduction of CO2 with H2O vapor is gaining increased interest because it is a promising “green chemistry” route for the direct conversion of CO2 to value‐added chemicals driven by solar energy. To increase the efficiency of photocatalytic conversion, most efforts are made by exploring various photocatalysts while little effort on advanced light management. For the first time, it is demonstrated that bio‐degradable transparent paper with excellent light diffusivity can effectively enhance the light utilization of photocatalytic reactions when attached on the device surface, and thus greatly increase the conversion efficiency. As a proof‐of‐concept, a graphitic carbon nitride (g‐C3N4) photocatalyst with transparent paper attached, exhibited 1.5 times higher photocatalytic activity than bare g‐C3N4 in the reduction of CO2 under visible light irradiation. The improved catalytic performance can be ascribed to the (1) refractive index matching and (2) enhanced light absorption via prolonged light traveling path in transparent paper, which decreases the light reflection at surface and traps the absorbed light inside, leading to an increased light absorption at the active layer of the device. The transparent paper with a controllable light management behavior has an unprecedented potential for applications in photocatalysis as a general method for improved light utilization. [ABSTRACT FROM AUTHOR]

High-performance, breathable, conductive, and flexible polypyrrole (PPy) coated paper electrodes are prepared by an interfacial polymerization method using air-laid paper as a substrate. Owing to the synergistic effect of superior electrical conductivity, high wettability, and the porous architecture, the prepared electrode not only shows an outstanding specific capacitance and rate abilities (3100 and 2579 mF cm−2 at 1 and 20 mA cm−2 for a PPy coated paper electrode), but also exhibits excellent flexibility, wearability, and breathability. Based on these superior features, an all-solid-state supercapacitor assembled with the PPy coated paper electrodes shows an outstanding energy density of 62.4 µW h cm−2, remarkable air permeability and excellent flexibility to sustain various deformations. Furthermore, large-scale fabrication of conductive flexible paper electrode can be easily achieved through this method. Therefore, this work offers a new vision for flexible energy storage. [ABSTRACT FROM AUTHOR]

Calcium metal batteries, as one of the promising alternatives beyond Li‐metal technology, is held back by the lack of suitable cathodes of considerable energy storage capability, and Ca anodes of long‐term stability and lower polarization potentials for Ca‐plating/stripping. Here, by recycling cellulose waste paper, feasible cathodes for Ca‐metal batteries of good high‐voltage and wide‐window‐voltage adaptability (0.005–4.9 V versus Ca/Ca2+), and impressive energy density (≈517.5 Wh kg−1 at 0.1 A g−1) are developed. Meanwhile, through tailorable Ca‐plating/stripping potentials (∆V≈ 0.65 V) realized by a modified electrolyte of Li+, Ca2+, BF4−, and PF6− multi‐ions system, the proof‐of‐concept Ca‐metal batteries not only delivered enhanced storage capability (101 mAh g−1 versus 51 mAh g−1 at 0.1 A g−1 in the window voltage of 2.0–4.7 V) and cycling stability (≈77% capacity retention for 100 cycles), but also simultaneously show a high output average working voltage of ≈3.2 V. The work provides a hint that mixed metal deposition under multi‐ions electrolyte system may address the challenging issues faced by single alkali or alkaline‐earth metal batteries. [ABSTRACT FROM AUTHOR]

Although the theoretical capacity of silicon is ten times higher than that of graphite, the overall electrode capacity of Si anodes is still low due to the low Si loading and heavy metal current collector. Here, a novel flexible 3D Si/C fiber paper electrode synthesized by simultaneously electrospraying nano-Si-PAN (polyacrylonitrile) clusters and electrospinning PAN fibers followed by carbonization is reported. The combined technology allows uniform incorporation of Si nanoparticles into a carbon textile matrix to form a nano-Si/carbon composite fiber paper. The flexible 3D Si/C fiber paper electrode demonstrate a very high overall capacity of ≈1600 mAh g-1 with capacity loss less than 0.079% per cycle for 600 cycles and excellent rate capability. The exceptional performance is attributed to the unique architecture of the flexible 3D Si/C fiber paper, i.e., the resilient and conductive carbon fiber network matrix, carbon-coated Si nanoparticle clusters, strong adhesion between carbon fibers and Si nanoparticle clusters, and uniform distribution of Si/C clusters in the carbon fiber frame. The scalable and facile synthesis method, good mechanical properties, and excellent electrochemical performance at a high Si loading make the flexible 3D Si/C fiber paper batteries extremely attractive for plug-in electric vehicles, flexible electronics, space exploration, and military applications. [ABSTRACT FROM AUTHOR]

Developing facile approaches to fit in large‐scale fabrication of efficient and durable catalytic electrodes is highly desirable for oxygen electrocatalysis and metal–air batteries. Herein, a strategy based on phase separation and laser induction is proposed to prepare 3D binder‐free integrated electrodes (IEs). The phase separation between a polybenzimidazole (PBI) solution and a coagulation bath containing metal precursors occurs to form a 3D interconnected porous catalyst precursor layer. After drying, IEs are obtained by laser induction, which simultaneously converts PBI into hierarchically porous laser‐induced graphene (HPLIG) and reduces metal precursor to tiny nanoparticles. To demonstrate the versatility of this method, IEs with different HPLIG hybrid catalyst layers and substrates are fabricated. IE‐NiFe/HPLIG and IE‐Co/HPLIG using carbon paper as a substrate exhibit superior oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance respectively. Flexible IE‐NiCoFe/HPLIG with OER and ORR bifunctionality using carbon cloth as the substrate is applied as an air cathode in rechargeable aqueous Zinc–air batteries (ZABs) and provides a satisfactory power density of 163 mW cm−2 and cycling stability of 1800 h at 10 mA cm−2. The electrode also endows solid ZABs with good flexibility. This work offers an industrially viable solution to the challenge of rapid fabrication of IEs. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are a very appealing power source with extremely high energy density. But the use of a metallic-Li anode causes serious safety hazards, such as short-circuiting and explosion of the cells. Replacing a sulfur cathode with a fully-lithiated lithium sulfide (Li2S) to pair with metallic-Li-free high-capacity anodes paves a feasible way to address this issue. However, the practical utility of Li2S cathodes faces the challenges of poor conductivity, sluggish activation process, and high sensitivity to moisture and oxygen that make electrode production more difficult than dealing with sulfur cathodes. Here, an efficient but low-cost strategy for easy production of freestanding flexible Li2S-based paper electrodes with very high mass and capacity loading in terms of in situ carbonthermal reduction of Li2SO4 by electrospinning carbon is reported. This chemistry enables high loading but strong affinity of ultrafine Li2S nanoparticles in a freestanding conductive carbon-nanofiber network, meanwhile greatly reducing the manufacturing complexity and cost of Li2S cathodes. Benefiting from enhanced structural stability and reaction kinetics, the areal specific capacities of such cathodes can be significantly boosted with less sacrificing of high-rate and cycling capability. This unique Li2S-cathode design can be directly applied for constructing metallic-Li-free or flexible Li-S batteries with high-energy density. [ABSTRACT FROM AUTHOR]

Described here is the production and characterization of a scalable method to produce 3D structured lithium ion battery anodes using free-standing papers of porous silicon nanowires (Si-NW) and graphene nanoribbons (GNRs). Using simple filtration methods, GNRs and Si-NWs can be entangled into a mat thereby forming Si-NW GNR papers. This produces anodes with high gravimetric capacity (up to 2500 mA h g−1) and high areal and volumetric capacities (up to 11 mA h cm−2 and 3960 mA h cm−3). The compact structure of the anode is possible since the GNR volume occupies a high proportion of empty space within the composite paper. These Si-NW/GNR papers have been cycled for over 300 cycles, exhibiting a stable life cycle. Combined with LiCoO2 nanowires, a full battery is produced with high energy density (386 Wh kg−1), meeting requirements for high performance devices. [ABSTRACT FROM AUTHOR]

As commercial interest in flexible power-conversion devices increases, the demand for high-performance alternatives to brittle inorganic thermoelectric (TE) materials is growing. As an alternative, we propose a rationally designed graphene/polymer/inorganic nanocrystal free-standing paper with high TE performance, high flexibility, and mechanical/chemical durability. The ternary hybrid system of the graphene/polymer/inorganic nanocrystal includes two hetero­junctions that induce double-carrier filtering, which significantly increases the electrical conductivity without a major decrease in the thermopower. The ternary hybrid shows a power factor of 143 μW m−1 K−1 at 300 K, which is one to two orders of magnitude higher than those of single- or binary-component materials. In addition, with five hybrid papers and polyethyleneimine (PEI)-doped single-walled carbon nanotubes (SWCNTs) as the p-type and n-type TE units, respectively, a maximum power density of 650 nW cm−2 at a temperature difference of 50 K can be obtained. The strategy proposed here can improve the performance of flexible TE materials by introducing more heterojunctions and optimizing carrier transfer at those junctions, and shows great potential for the preparation of flexible or wearable power-conversion devices. [ABSTRACT FROM AUTHOR]

A new paper‐based anti‐reflection coating for solar cells is presented showing a large reduction in the reflection over the entire solar spectrum for a wide range of angles. This process is simple and inexpensive, requiring no high temperature or vacuum‐based processing, and is made from renewable cellulose fibers. [ABSTRACT FROM AUTHOR]

A novel nanocomposite cathode consisting of sulfur and hollow-mesoporous titania (HMT) embedded within carbon nanotubes (CNT), which is designated as S-HMT@CNT, has been obtained by encapsulating elemental sulfur into the pores of hollow-mesoporous, spherical TiO2 particles that are connected via CNT. A carbon-paper interlayer, referred to as dual functional porous carbon wall (DF-PCW), has been obtained by filling the voids in TiO2 spheres with carbon and then etching the TiO2 template with a chemical process. The DF-PCW interlayer provides a medium for scavenging the lithium polysulfides and suppressing them from diffusing to the anode side when it is inserted between the sulfur cathode and the separator. Lithium-sulfur cells fabricated with the thus prepared S-HMT@CNT cathode and the DF-PCW interlayer exhibit superior performance due to the containment of sulfur in TiO2 and improved lithium-ion and electron transports. The Li-S cells display high capacity with excellent capacity retention at rates as high as 1C, 2C, and 5C rates. [ABSTRACT FROM AUTHOR]

Supercapacitors based on freestanding and flexible electrodes that can be fabricated with bacterial cellulose (BC), multiwalled carbon nanotubes (MWCNTs), and polyaniline (PANI) are reported. Due to the porous structure and electrolyte absorption properties of the BC paper, the flexible BC-MWCNTs-PANI hybrid electrode exhibits appreciable specific capacitance (656 F g−1 at a discharge current density of 1 A g−1) and remarkable cycling stability with capacitance degradation less than 0.5% after 1000 charge-discharge cycles at a current density of 10 A g−1. The facile and low-cost of this binder-free paper electrode may have great potential in development of flexible energy-storage devices. [ABSTRACT FROM AUTHOR]

Asymmetric supercapacitors featuring both high energy and power densities as well as a long lifespan are much sought after and may become a reality depending on the availability of cheap yet highly active electrode materials. Here, a novel flexible architecture electrode made of NiCoAl-layered double hydroxide (NiCoAl-LDH) nanoplates coupled with NiCo-carbonate hydroxide (NiCo-CH) nanowires, grown on graphite paper via an in situ, one-step, hydrothermal method is reported. The nanowire-like NiCo-CH species in the nanoplate matrix function as a scaffold and support the dispersion of the NiCoAl-LDH nanoplates, resulting in a relatively loose and open structure within the electrode matrix. Asymmetric supercapacitors fabricated using the nanohybrids as the positive electrode and a typical activated carbon (AC) as negative electrode show a high energy density of 58.9 Wh kg−1 at a power density of 0.4 kW kg−1, which is based on the total mass of active materials at a voltage of 1.6 V. An energy density of 14.9 Wh kg−1 can be retained even at a high power density of 51.5 kW kg−1. Our asymmetric supercapacitor also exhibits an excellent long cycle life, whereby a specific capacitance of 97% is retained even after 10 000 cycles. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐iodine battery (AZIB) has the advantage of low cost and high specific capacity but suffer from the soluble polyiodides shuttling and sluggish redox kinetics. Herein, these two limitations are addressed by employing a cathode additive (zirconium hydrogen phosphate, denoted as EI‐ZrP) which provides dual functions: an agent for polyiodide confinement, and abundant channels for zinc ion transport. An enlarged crystalline interlayer (from typical 7.5 to 18.3 Å) of the EI‐ZrP significantly enhances the ionic conductivity and simultaneously immobilizes polyiodides, leading to an accelerated conversion process. AZIB with EI‐ZrP in the iodine cathode exhibits a high capacity retention over 10,000 cycles (with a 0.02‰ decay rate per cycle). Quasi‐solid‐state Zn‐I2 pouch cell has been constructed using hydrogel‐paper as separator and EI‐ZrP additive, which delivers a high areal capacity under repeated bending. As a proof‐of‐concept demonstration, the paper battery is integrated to power a wireless flexible pressure sensor system (WFPSS). This strategy may shed light on the rational design of conversion‐type cathode materials for both energy storage and flexible portable electronics. [ABSTRACT FROM AUTHOR]

The design and synthesis of 2D heterostructured materials for water splitting are normally based on van der Waals (vdW) nanosheets, but this approach is gradually approaching a performance ceiling in terms of activity and stability. Herein, a novel heterostructured system is explored based on 2D non‐vdW and conductive nanosheets. Notably, the interplanar growth of 2D non‐vdW Co2N nanosheets is realized between graphene layers in the current collector of carbon fiber papers (CPs), generating an interlocking structure within CPs. The exposed surface of Co2N nanosheets possesses a high surface energy that anchors highly active CoNC, forming 2D CoNC@Co2N heterostructures outside CPs. This integrated electrocatalytic system bridged by non‐vdW Co2N nanosheets presents a low overpotential of 1.52 V and an excellent stability of 280 h, which outperform most bifunctional and nonprecious‐metal‐based electrocatalysts in alkaline media, owing to the nature of 2D non‐vdW nanosheets and the formation of strong and conductive connections among CoNC, nanosheets, and CPs. [ABSTRACT FROM AUTHOR]

The critical challenges of Li-O2 batteries lie in sluggish oxygen redox kinetics and undesirable parasitic reactions during the oxygen reduction reaction and oxygen evolution reaction processes, inducing large overpotential and inferior cycle stability. Herein, an elaborately designed 3D hierarchical heterostructure comprising NiCO2S4@NiO core-shell arrays on conductive carbon paper is first reported as a freestanding cathode for Li-O2 batteries. The unique hierarchical array structures can build up multidimensional channels for oxygen diffusion and electrolyte impregnation. A built-in interfacial potential between NiCO2S4 and NiO can drastically enhance interfacial charge transfer kinetics. According to density functional theory calculations, intrinsic LiO2-affinity characteristics of NiCO2S4 and NiO play an importantly synergistic role in promoting the formation of large peasecodlike Li2O2, conducive to construct a low-impedance Li2O2/cathode contact interface. As expected, Li-O2 cells based on NiCO2S4@NiO electrode exhibit an improved overpotential of 0.88 V, a high discharge capacity of 10 050 mAh g-1 at 200 mA g-1, an excellent rate capability of 6150 mAh g-1 at 1.0 A g-1, and a long-term cycle stability under a restricted capacity of 1000 mAh g-1 at 200 mA g-1. Notably, the reported strategy about heterostructure accouplement may pave a new avenue for the effective electrocatalyst design for Li-O2 batteries. [ABSTRACT FROM AUTHOR]

Abstract: The self‐standing electrode nanomaterials with highly effective bifunctional electrocatalysis for oxygen reduction and evolution reactions (ORR/OER) are important for practical applications in metal–air batteries. Herein, a defect‐enriched and pyridinic‐N (PN) dominated bifunctional electrocatalyst with novel core–shell architecture (DN‐CP@G) is successfully fabricated by in situ exfoliating graphene from carbon paper followed by high temperature ammonia treatment. Benefitting from its strongly coupled core–shell structure, abundant defective sites and high‐content PN dopants, the DN‐CP@G displays an excellent electrocatalytic (ORR and OER) activity and stability in alkaline media, which are comparable to commercial Pt/C and Ir/C catalysts. The experiment, and theoretical calculations demonstrate that the electrocatalytic activities of carbon materials strongly depend on their defective sites and PN dopants. By directly using DN‐CP@G as a self‐standing electrode, the assembled zinc–air battery demonstrates a high discharge performance and outstanding long‐term cycle stability with at least 250 cycles, which is much superior to the mixed Pt/C and Ir/C electrodes. Remarkably, the DN‐CP@G based all‐solid‐state battery also reveals a good discharge and cycle performance. A facile and cost‐efficient approach to prepare highly effective bifunctional self‐standing electrode is provided by in situ generation of active sites on carbon support for metal–air batteries. [ABSTRACT FROM AUTHOR]

Composites of polypyrrole (PPy) and Cladophora nanocellulose, reinforced with 8 μm-thick chopped carbon filaments, can be used as electrode materials to obtain paper-based energy-storage devices with unprecedented performance at high charge and discharge rates. Charge capacities of more than 200 C g−1 (PPy) are obtained for paper-based electrodes at potential scan rates as high as 500 mV s−1, whereas cell capacitances of ∼60-70 F g−1 (PPy) are reached for symmetric supercapacitor cells with capacitances up to 3.0 F (i.e.,0.48 F cm−2) when charged to 0.6 V using current densities as high as 31 A g−1 based on the PPy weight (i.e., 99 mA cm−2). Energy and power densities of 1.75 Wh kg−1 and 2.7 kW kg−1, respectively, are obtained when normalized with respect to twice the PPy weight of the smaller electrode. No loss in cell capacitance is seen during charging/discharging at 7.7 A g−1 (PPy) over 1500 cycles. It is proposed that the nonelectroactive carbon filaments decrease the contact resistances and the resistance of the reduced PPy composite. The present straightforward approach represents significant progress in the development of low-cost and environmentally friendly paper-based energy-storage devices for high-power applications. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editor discusses the changes within the issue, including the switch to article numbers from page numbers, increase in publication space, and the criteria for judging scientific work.

A flexible asymmetric supercapacitor (ASC) with high energy density is designed and fabricated using flower-like Bi2O3 and MnO2 grown on carbon nanofiber (CNF) paper as the negative and positive electrodes, respectively. The lightweight (1.6 mg cm−2), porous, conductive, and flexible features make the CNF paper an ideal support for guest active materials, which permit a large areal mass of 9 mg cm−2 for Bi2O3 (≈85 wt% of the entire electrode). Thus, the optimal device with an operation voltage of 1.8 V can deliver a high energy density of 43.4 μWh cm−2 (11.3 W h kg−1, based on the total electrodes) and a maximum power density of 12.9 mW cm−2 (3370 W kg−1). This work provides an example of large areal mass and flexible electrode for ASCs with high areal capacitance and high energy density, holding great promise for future flexible electronic devices. [ABSTRACT FROM AUTHOR]

Photocatalytic carbon dioxide reduction reaction (CO2RR) is widely recognized as an attractive technology for simultaneously addressing environmental issues and energy crises. CO2RR encompasses three primary processes: electron‐hole generation, electron‐hole separation, and surface catalysis. Consequently, the light absorption capacity, charge separation ability, and selectivity of the surface catalytic site of the photocatalyst significantly influence the rate of CO2RR. The significant role of strain engineering in the photocatalytic reduction of carbon dioxide to solar fuel using semiconductor catalysts is reviewed in this paper. Specifically, the design strategies of strain catalysts and the crucial role of strain on CO2RR are examined. In this paper, the mechanisms of strain‐enhanced light absorption, photoelectron‐hole separation, and product selectivity are reviewed, along with the most recent advancements in this field. This review offers valuable information for the design of strain engineering photocatalysts and supplements the review of various semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

In this paper, compositions within the TiZrAlCrMn, TiZrAlCrFe, and TiZrAlMnFe alloy systems that form the C14 Laves phase are investigated. The design, synthesis, structural, and hydrogen storage characterizations for an equiatomic and a non‐equiatomic composition for each alloy system are presented. Additionally, the further development of a thermodynamic method for the calculation of pressure‐composition‐isotherms (PCIs) is presented of C14 Laves phase alloys that absorb hydrogen by solid solution. Overall, the results shown in this paper indicate that Al‐containing multicomponent alloys can present promising hydrogen storage performance under high pressures. Nonetheless, high concentrations of aluminum in highly concentrated (equiatomic) alloys can have a negative impact on the hydrogenation properties. The Ti0.29Zr0.05Al0.05Cr0.26Mn0.35 composition showed promising hydrogenation/dehydrogenation properties. The gravimetric capacity of this alloy is ≈1.76 wt.% H2 and the PCIs measured indicate that this material has potential for high‐pressure hydrogen storage and compression applications. The use of the presented thermodynamic model for the design of multicomponent alloys is suggested. [ABSTRACT FROM AUTHOR]

In article number 1401660, Tim‐Patrick Fellinger and co‐workers show that it is possible to make highly active and cheap catalysts using an easy‐to‐do recipe. The cover image illustrates that rain splits at the interface of gemstones and carbonized paper. This indicates the symbiotic interaction of nickel oxide nanoparticles and nitrogen‐doped carbon, which leads to a bifunctional water‐splitting electrocatalyst. [ABSTRACT FROM AUTHOR]

The newly invented triboelectric nanogenerator (TENG) is deemed to be a more efficient strategy than an electromagnetic generator (EMG) in harvesting low‐frequency (<2 Hz) water wave energy. Various TENGs with different structures and functions for blue energy have been developed, which can be roughly divided into two types: liquid–solid contact electrification TENGs and fully enclosed solid–solid contact electrification TENGs. Robustness and packaging are critical factors in the development of TENGs toward practical applications. Furthermore, for fully enclosed TENGs, the requirements and costs of packaging are very high, and they can difficult to disassemble after enclosed, if there is something wrong with the devices. Herein, a nonencapsulative pendulum‐like paper based hybrid nanogenerator for energy harvesting is designed, which mainly consists of three parts, one solar panel, two paper based zigzag multilayered TENGs, and three EMG units. This unique structure reveals the superior robustness and a maximum peak power of zigzag multilayered TENGs up to 22.5 mW is realized. Moreover, the device can be used to collect the mechanical energy of human motion in hand shaking. This work presents a new platform of hybrid generators toward energy harvesting as a portable practical power source, which has potential applications in navigation and lighting. [ABSTRACT FROM AUTHOR]

In article number 1301655, Mingkui Wang, Guang Yang, Yan Shen, and co‐workers describe a simple and convenient method for fabricating freestanding and flexible paper electrodes based on bacterial cellulose, multiwalled carbon nanotubes, and a polyaniline composite. The hybrid paper exhibits impressive electrochemical performance and is a promising candidate as a new electrode material for assembling a lightweight and low‐cost energy storage device as the power for stretchable/flexible electronic devices. [ABSTRACT FROM AUTHOR]

In article number 1301804, Jeremy N. Munday and co‐workers describe the use of a plant‐based cellulose fiber paper as advanced antireflection coatings for solar cells. These coatings provide broadband, angle‐independent optical response using a simple and inexpensive fabrication process. Additionally, these cellulose materials are lightweight, flexible, and recyclable, making them highly attractive materials for environmentally friendly production. [ABSTRACT FROM AUTHOR]

The uncontrolled crystallization of perovskite generates a significant number of internal and interfacial defects, posing a major challenge to the performance of perovskite solar cells (PSCs). In this paper, a novel bi‐interfacial modification strategy utilizing 5‐fluoropyridinic acid (FPA) is proposed to modulate crystal growth and provide defect passivation. It is demonstrated that FPA is self‐deposited at both the top and bottom interfaces of perovskite films during thermal annealing. The CO and N functional groups in FPA serve as chelating agents, binding closely to uncoordinated Pb2+/Pb clusters, thereby passivating defects and reducing charge recombination at the interfaces. The strong chemical interactions between FPA and Pb further stabilize the Pb‐I framework, promoting the formation of high‐quality perovskite films, as confirmed by in situ photoluminescence measurements. Consequently, the modified inverted PSCs achieved an exceptional power conversion efficiency (PCE) of 25.37%. Moreover, the devices retained over 93.17% of initial efficiency after 3000 h of continuous illumination under one‐sun equivalent conditions in a nitrogen atmosphere. This paper presents a promising pathway for enhancing the performance and stability of inverted PSCs through a self‐induced bi‐interfacial modification approach. [ABSTRACT FROM AUTHOR]

One of the biggest challenges we will face over the next few decades is finding a way to power the future while maintaining strong socioeconomic growth and a clean environment. A transition from the use of fossil fuels to renewable energy sources is expected. Cellulose, the most abundant natural biopolymer on earth, is a unique, sustainable, functional material with exciting properties: it is low-cost and has hierarchical fibrous structures, a high surface area, thermal stability, hydrophilicity, biocompatibility, and mechanical flexibility, which makes it ideal for use in sustainable, flexible energy storage devices. This review focuses on energy storage applications involving different forms of cellulose (i.e., cellulose microfibers, nanocellulose fibers, and cellulose nanocrystals) in supercapacitors, with particular emphasis on new trends and performance considerations relevant to these fields. Recent advances and approaches to obtaining high capacity devices are evaluated and the limitations of cellulose-based systems are discussed. For the first time, a combination of device-specific factors such as electrode structures, mass loadings, areal capacities, and volumetric properties are taken into account, so as to evaluate and compare the energy storage performance and to better assess the merits of cellulose-based materials with respect to real applications. [ABSTRACT FROM AUTHOR]

Smart construction of ultraflexible electrodes with superior gravimetric and volumetric capacities is still challenging yet significant for sodium ion batteries (SIBs) toward wearable electronic devices. Herein, a hybrid film made of hierarchical Fe1−xS‐filled porous carbon nanowires/reduced graphene oxide (Fe1−xS@PCNWs/rGO) is synthesized through a facile assembly and sulfuration strategy. The resultant hybrid paper exhibits high flexibility and structural stability. The multidimensional paper architecture possesses several advantages, including rendering an efficient electron/ion transport network, buffering the volume expansion of Fe1−xS nanoparticles, mitigating the dissolution of polysulfides, and enabling superior kinetics toward efficient sodium storage. When evaluated as a self‐supporting anode for SIBs, the Fe1−xS@PCNWs/rGO paper electrode exhibits remarkable reversible capacities of 573–89 mAh g−1 over 100 consecutive cycles at 0.1 A g−1 with areal mass loadings of 0.9–11.2 mg cm−2 and high volumetric capacities of 424–180 mAh cm−3 in the current density range of 0.2–5 A g−1. More competitively, a SIB based on this flexible Fe1−xS@PCNWs/rGO anode demonstrates outstanding electrochemical properties, thus highlighting its enormous potential in versatile flexible and wearable applications. A highly flexible Fe1−xS@PCNWs/rGO hybrid paper electrode with robust mechanical properties is successfully fabricated and shown to exhibit superior sodium storage properties with high volumetric and gravimetric capacities. Using this paper anode, a flexible sodium ion battery is also fabricated and shown to exhibit promising performance. [ABSTRACT FROM AUTHOR]

Developing biodegradable electrodes is a significant step toward environmental sustainability and cost reduction in battery technology. This paper presents a new approach that utilizes metal‐organic framework (MOF)‐encapsulated silicon nanoparticles (SiNPs) as the active anode material within a cellulose‐based electrode. The electrode is free‐standing, flexible, biodegradable, and significantly reduces the strain experienced by SiNPs during volume expansion, resulting in improved capacity and cycle life stability of SiNPs. The high porosity of the electrode creates efficient lithium (Li+) ion transport channels and enhances electrolyte absorption, thus promoting effective contact between the electrolyte and active material. The outcome is rapid electrode kinetics and a highly reversible discharge capacity of 1744.6 mAh g−1 at 0.5 A g−1 versus Li/Li+ over 1000 cycles. Further, full cell tests are conducted that demonstrate a stable cycle performance exceeding 3400 cycles, with an initial discharge capacity retention of 80.5% at 0.5 A g−1. By employing cellulose and avoiding toxic organic solvents and binders, the proposed approach is promising for a substantial reduction of the production costs of Li‐ion batteries. The scalability of the proposed method further enhances its practical viability, offering intriguing economic implications for the future of battery technology. [ABSTRACT FROM AUTHOR]

Alkaline all‐iron flow batteries possess intrinsic safety and low cost, demonstrating great potential for large‐scale and long‐duration energy storage. However, their commercial application is hindered by the issue of capacity decay resulting from the decomposition of iron complexes and ligand crossovers. In this paper, an robust anolyte Fe(TEA‐2S) is reported, which is formed by chelating iron ions with the sulfonate‐enriched ligand (TEA‐2S) in alkaline environment. By skillfully designing the ligands, the binding energy of the iron complexes increases and ligand crossovers are suppressed, making the iron complexes highly stable in the charge–discharge cycles. Alkaline all‐iron flow batteries coupling with Fe(TEA‐2S) and the typical iron‐cyanide catholyte perform a minimal capacity decay rate (0.17% per day and 0.0014% per cycle), maintaining an average coulombic efficiency of close to 99.93% over 2000 cycles along with a high energy efficiency of 83.5% at a current density of 80 mA cm−2. In addition, Fe(TEA‐2S) exhibits high solubility of up to 1.85 м (with a theoretical capacity of up to 49.58 Ah L−1), even at low temperatures as extreme as −30 °C. This work demonstrates a promising pathway toward achieving long‐duration and large‐scale energy storage. [ABSTRACT FROM AUTHOR]