Horizontally Arranged Zn Platelet Deposition Regulated by Bi2O3/Bi toward High-Rate and Dendrite-Free 3D Zn Composite Anode.

Aqueous Zn-metal battery is considered as a promising energy-storage system. However, uncontrolled zinc dendrite growth is the main cause of short-circuit failure in aqueous Zn-based batteries. One of the most efficient and convenient strategies to alleviate this issue is to introduce appropriate zincophilic nucleation sites to guide zinc metal deposition and regulate crystal growth. Herein, this work proposes Bi2O3/Bi nanosheets anchored on the cell wall surface of the 3D porous conductive host as the Zn deposition sites to modulate Zn deposition behavior and hence inhibit the zinc dendrite growth. Density functional theory and experimental results demonstrate that Bi2O3 has a super zinc binding energy and strong adsorption energy with zinc (002) plane, as a super-zincophilic nucleation site, which results in the deposition of zinc preferentially along the horizontal direction of (002) crystal plane, fundamentally avoids the formation of Zn dendrites. Benefiting from the synergistic effect Bi2O3/Bi zincophilic sites and 3D porous structure in the B-BOGC host, the electrochemical performance of the constructed Zn-based battery is significantly improved. As a result, the Zn anode cycles for 1500 cycles at 50 mA cm-2 and 1.0 mAh cm-2. Meanwhile, the Zn@B-BOGC//MnO2 full cell can operate stably for 2000 cycles at 2.0 A g-1.

Anchoring Polar Organic Molecules in Defective Ammonium Vanadate for High-Performance Flexible Aqueous Zinc-Ion Battery.

Ammonium vanadate (NVO) often has unsatisfactory electrochemical performance due to the irreversible removal of NH4 + during the reaction. Herein, layered DMF-NVO nanoflake arrays (NFAs) grown on highly conductive carbon cloth (CC) are employed as the binder-free cathode (DMF-NVO NFAs/CC), which produces an enlarged interlayer spacing of 12.6 Å (against 9.5 Å for NH4 V4 O10 ) by effective N, N-dimethylformamide (DMF) intercalation. Furthermore, the strong attraction of highly polar carbonyl and ammonium ions in DMF can stabilize the lattice structure, and low-polar alkyl groups can interact with the weak electrostatic generated by Zn2+ , which allows Zn2+ to be freely intercalated. The DMF-NVO NFAs/CC//Zn battery exhibits an impressive high capacity of 536 mAh g-1 at 0.5 A g-1 , excellent rate capability, and cycling performance. The results of density functional theory simulation demonstrate that the intercalation of DMF can significantly reduce the band gap and the diffusion barrier of Zn2+ , and can also accommodate more Zn2+ . The assembled flexible aqueous rechargeable zinc ion batteries (FARZIBs) exhibit outstanding energy density and power density, up to 436 Wh kg-1 at 400 W kg-1 , and still remains 180 Wh kg-1 at 4000 W kg-1 . This work can provide a reference for the design of cathode materials for high-performance FARZIBs.

Interfacial Control of NiCoP@NiCoP Core-Shell Nanoflake Arrays as Advanced Cathodes for Ultrahigh-Energy-Density Fiber-Shaped Asymmetric Supercapacitors.

Efficient improvement of the energy density and overall electrochemical performance of fiber-shaped asymmetric supercapacitors (FASCs) for practical applications in portable and wearable electronics requires highly electrochemically active materials and a rational design. Herein, two-step phosphorization (TSP) processes are performed to directly grow 3D well-aligned NiCoP@NiCoP (NCP@NCP TSP) nanoflake arrays (NFAs) on carbon nanotube fibers (CNTFs). Profiting from the metallic characteristics and excellent electrochemical performance of NiCoP and the hierarchical design of the core-shell heterostructure, the NCP@NCP TSP NFAs/CNTF hybrid electrode exhibits significantly improved electrochemical performance. The as-fabricated NCP@NCP TSP NFAs/CNTF electrode possesses an ultrahigh areal capacitance of 10 035 mF cm-2 at a current density of 1 mA cm-2 , with excellent rate capability and cycling stability. Furthermore, an FASC device with a maximum operating voltage of 1.6 V is assembled by adopting NCP@NCP TSP NFAs/CNTF as a positive electrode, hierarchical TiN@VN core-shell heterostructure nanowire arrays (NWAs)/CNTF as negative electrode, and KOH-PVA as a gel electrolyte. The FASC device exhibits a high areal capacitance of 430.4 mF cm-2 and an ultrahigh energy density of 51.02 mWh cm-3 . Thus, the rationally designed NiCoP@NiCoP electrode is a promising candidate for incorporation into next-generation wearable and portable energy-storage devices.

Flexible and High-Voltage Coaxial-Fiber Aqueous Rechargeable Zinc-Ion Battery.

Extensive efforts have been devoted to construct a fiber-shaped energy-storage device to fulfill the increasing demand for power consumption of textile-based wearable electronics. Despite the myriad of available material selections and device architectures, it is still fundamentally challenging to develop eco-friendly fiber-shaped aqueous rechargeable batteries (FARBs) on a single-fiber architecture with high energy density and long-term stability. Here, we demonstrate flexible and high-voltage coaxial-fiber aqueous rechargeable zinc-ion batteries (CARZIBs). By utilizing a novel spherical zinc hexacyanoferrate with prominent electrochemical performance as cathode material, the assembled CARZIB offers a large capacity of 100.2 mAh cm-3 and a high energy density of 195.39 mWh cm-3, outperforming the state-of-the-art FARBs. Moreover, the resulting CARZIB delivers outstanding flexibility with the capacity retention of 93.2% after bending 3000 times. Last, high operating voltage and output current are achieved by the serial and parallel connection of CARZIBs woven into the flexible textile to power high-energy-consuming devices. Thus, this work provides proof-of-concept design for next-generation wearable energy-storage devices.

Ammonium-tungstate-promoted growth of boron nitride nanotubes.

Ammonium tungstate ((NH4)10W12O41 · xH2O) is a kind of oxygen-containing ammonium salt. The following study proves that it can be successfully used as a metal oxide alternative to produce boron oxide (B2O2) by oxidizing boron (B) in a traditional boron oxide chemical vapor deposition (BOCVD) process. This special oxidant promotes the simplistic fabrication of boron nitride nanotubes (BNNTs) in a conventional horizontal tube furnace, an outcome which may have resulted from its strong oxidizability. The experimental results demonstrate that the mole ratio of B and (NH4)10W12O41 · xH2O is a key parameter in determining the formation, quality and quantity of BNNTs when stainless steel is employed as a catalyst. We also found that Mg(NO3)2 and MgO nanoparticles (NPs) can be used as catalysts to grow BNNTs with the same precursor. The BNNTs obtained from the Mg(NO3)2 catalyst were straighter than those obtained from the MgO NP catalyst. This could have been due to the different physical forms of the catalysts that were used.

Long-Lifespan Fibrous Aqueous Ni//Bi Battery Enabled by Bi2O3-Bi2S3 Hierarchical Heterostructures.

Bismuth oxide (Bi2O3) materials are considered as great promising anodes for aqueous batteries on account of the high capacity as well as wide potential plateau. Nevertheless, the low conductivity and severe volumetric change of Bi2O3 in the course of cycling are the main limiting factors for their application in energy-storage systems. Herein, we propose and design unique hierarchical heterostructures constructed by Bi2O3 and Bi2S3 nanosheets (NSs) manufactured immediately on the surface of carbon nanotube fibers (CNTFs). The Bi2O3-Bi2S3 (BO-BS) exhibits enhanced conductivity and increased stability in comparison with pure Bi2O3 and Bi2S3. The BO-BS NSs/CNTF electrode indicates exceptional rate capability and cycling stability, while creating a high reversible capacity of 0.68 mAh cm-2 at 4 mA cm-2, as anticipated. Additionally, the quasi-solid-state fibrous aqueous Ni//Bi battery that was built with the BO-BS NSs/CNTF anode delivers an exceptional cycling stability of 52.7% capacity retention after 4000 cycles at 80 mA cm-2, an ultrahigh capacity of 0.35 mAh cm-2 at 4 mA cm-2, and a high energy density of 340.1 mWh cm-3 at 880 mW cm-3. This work demonstrates the potential of constructing hierarchical heterostructures of bismuth-based materials for high-performance aqueous Ni//Bi batteries and other energy-storage devices.

Organic molecule-assisted intermediate adsorption for conversion of CO2 to CO by electrocatalysis.

Currently, Zn-based catalysts for electrochemical CO2 reduction reactions are limited by their moderate carbophilicity, resulting in low catalytic activity and CO selectivity. To this end, we selected 5-mercapto-1-methylimidazole, a small molecule that possesses the ability to both coordinate to Zn and interact with the intermediates, to modify electrochemically deposited Zn nanosheets. The interaction between them effectively enhances intermediate adsorption by lowering the Gibbs free energy, which leads to an increase of the Faraday efficiency to 1.9 times and the CO partial current density to 3.0 times that of the pristine sample (-1.0 V vs. RHE).

High-Efficiency Electromagnetic Interference Shielding from Highly Aligned MXene Porous Composites via Controlled Directional Freezing.

Lightweight porous composite materials (PCMs) with outstanding electromagnetic interference (EMI) shielding performances are ideal for aerospace, artificial intelligence, military, and other fields. Herein, a three-dimensional Ti3C2Tx MXene/sodium alginate (SA)/carbon nanotubes (CNTs) (MSC) PCMs was prepared by a controlled directional freezing process. This method constructs a directionally ordered porous structure, which can make the incident electromagnetic waves reflect and scattered several times in the PCMs. The introduction of CNTs into the MSC PCMs can form three-dimensional conductive networks with MXene, thus improving the conductivity and further improving the electromagnetic shielding performance. Furthermore, the SA with abundant hydrogen bonding can strengthen the interlayer interaction between MXene and CNTs. Profiting from the controlled directional freezing and highly aligned porous structure, the MSC PCMs with 75 wt % CNTs exhibit ultrahigh conductivity of 1630 S m-1, an ultrahigh EMI shielding effectiveness of 48.0 dB in X-band for electromagnetic waves incident perpendicular to the hole growth direction, and compressive strength of 72.3 kPa. The as-prepared MSC PCMs show excellent EMI shielding and mechanical properties and have significant applications in the preparation of an entirely novel type of EMI shielding materials with an absorption-based mechanism.

In Situ Construction of Heterostructured Co3O4/CoP Nanoflake Arrays on Carbon Cloth as Binder-Free Anode for High-Performance Lithium-Ion Batteries.

Cobalt oxide (Co3O4) is regarded as the anode material for lithium-ion batteries (LIBs) with great research value owing to its environmental friendliness and exceptional theoretical capacity. However, the low intrinsic conductivity, poor electrochemical kinetics, and unsatisfactory cycling performance severely limit its practical applications in LIBs. The construction of a self-standing electrode with heterostructure by introducing a highly conductive cobalt-based compound is an effective strategy to solve the above issues. Herein, Co3O4/CoP nanoflake arrays (NFAs) with heterostructure are constructed skillfully directly grown on carbon cloth (CC) by in situ phosphorization as an anode for LIBs. Density functional theory simulation results demonstrate that the construction of heterostructure greatly increases the electronic conductivity and Li ion adsorption energy. The Co3O4/CoP NFAs/CC exhibited an extraordinary capacity (1490.7 mA h g-l at 0.1 A g-l) and excellent performance at high current density (769.1 mA h g-l at 2.0 A g-l), as well as remarkable cyclic stability (451.3 mA h g-l after 300 cycles with a 58.7% capacity retention rate). The reasonable construction of heterostructure can promote the interfacial ion transport, significantly enhance the adsorption energy of lithium ions, improve the conductivity of Co3O4 electrode material, promote the partial charge transfer throughout the charge and discharge cycles, and enhance the overall electrochemical performance of the material.

Superstructured α-Fe2O3 nanorods as novel binder-free anodes for high-performing fiber-shaped Ni/Fe battery.

Fiber-shaped energy storage devices areindispensableparts of wearable and portable electronics. Aqueous rechargeable Ni/Fe battery is a very appropriate energy storage device due to their good safety without organic electrolytes, high ionic conductivity, and low cost. Unfortunately, the low energy density, poor power density and cycling performance hinder its further practical applications. In this study, in order to obtain high performance negative iron-based material, we first synthesized α-iron oxide (α-Fe2O3) nanorods (NRs) with superstructures on the surface of highly conductive carbon nanotube fibers (CNTFs), then electrically conductive polypyrrole (PPy) was coated to enhance the electron, ion diffusion and cycle stability. Theas-prepared α-Fe2O3@PPy NRs/CNTF electrode shows a high specific capacity of 0.62 Ah cm-3 at the current density of 1 A cm-3. Furthermore, the Ni/Fe battery that was assembled by the above negative electrode shows a maximum volumetric energy density of 15.47 mWh cm-3 with 228.2 mW cm-3 at a current density of 1 A cm-3. The cycling durability and mechanical flexibility of the Ni/Fe battery were tested, which show good prospect for practical application. In summary, these merits make it possible for our Ni/Fe battery to have practical applications in next generation flexible energy storage devices.

High-Performance and Ultraflexible Aqueous Rechargeable Lithium-Ion Batteries Developed by Constructing All Binder-free Electrode Materials.

Aqueous rechargeable lithium-ion batteries (ARLIBs) as alternative energy storage devices have attracted tremendous attention because of their low cost and high safety. However, it is still a significant challenge to develop flexible high-performance ARLIBs for powering wearable devices because of the lack of all binder-free electrode materials. In this study, we develop one-step hydro-/solvothermal methods to design binder-free electrodes of LiCoO2 polygonal-sheeted arrays and rugby ball-shaped NaTi2(PO4)3 on carbon nanotube fibers as the cathode (LCO@CNTF) and the anode (NTP@CNTF). Both the electrodes are prepared at low temperatures without an extra calcination process, which is a great improvement for the growth process. The electrodes deliver remarkable capacity and extraordinary rate performance in a saturated Li2SO4 solution. Meanwhile, because of the synergy of LCO@CNTF and NTP@CNTF, an impressive capacity of 45.24 mA h cm-3 and an admirable energy density of 67.86 mW h cm-3 are achieved for the assembled quasi-solid-state fiber-shaped flexible ARLIB (FARLIB), which outperform most reported fiber-shaped aqueous rechargeable batteries. More encouragingly, our FARLIB possesses good flexibility, with a 94.74% capacity retention after bending 3000 times. Thus, this work represents a significant step toward developing FARLIBs and provides a new prospect in the design of wearable energy storage devices.

All Binder-Free Electrodes for High-Performance Wearable Aqueous Rechargeable Sodium-Ion Batteries.

Extensive efforts have recently been devoted to the construction of aqueous rechargeable sodium-ion batteries (ARSIBs) for large-scale energy-storage applications due to their desired properties of abundant sodium resources and inherently safer aqueous electrolytes. However, it is still a significant challenge to develop highly flexible ARSIBs ascribing to the lack of flexible electrode materials. In this work, nanocube-like KNiFe(CN)6 (KNHCF) and rugby ball-like NaTi2(PO4)3 (NTP) are grown on carbon nanotube fibers via simple and mild methods as the flexible binder-free cathode (KNHCF@CNTF) and anode (NTP@CNTF), respectively. Taking advantage of their high conductivity, fast charge transport paths, and large accessible surface area, the as-fabricated binder-free electrodes display admirable electrochemical performance. Inspired by the remarkable flexibility of the binder-free electrodes and the synergy of KNHCF@CNTF and NTP@CNTF, a high-performance quasi-solid-state fiber-shaped ARSIB (FARSIB) is successfully assembled for the first time. Significantly, the as-assembled FARSIB possesses a high capacity of 34.21 mAh cm-3 and impressive energy density of 39.32 mWh cm-3. More encouragingly, our FARSIB delivers superior mechanical flexibility with only 5.7% of initial capacity loss after bending at 90° for over 3000 cycles. Thus, this work opens up an avenue to design ultraflexible ARSIBs based on all binder-free electrodes for powering wearable and portable electronics.

All Hierarchical Core-Shell Heterostructures as Novel Binder-Free Electrode Materials for Ultrahigh-Energy-Density Wearable Asymmetric Supercapacitors.

High-performance fiber-shaped energy-storage devices are indispensable for the development of portable and wearable electronics. Composite pseudocapacitance materials with hierarchical core-shell heterostructures hold great potential for the fabrication of high-performance asymmetric supercapacitors (ASCs). However, few reports concerning the assembly of fiber-shaped ASCs (FASCs) using cathode/anode materials with all hierarchical core-shell heterostructures are available. Here, cobalt-nickel-oxide@nickel hydroxide nanowire arrays (NWAs) and titanium nitride@vanadium nitride NWAs are constructed skillfully with all hierarchical core-shell heterostructures directly grown on carbon nanotube fibers and are shown to exhibit ultrahigh capacity and specific capacitance, respectively. The specific features and outstanding electrochemical performances of the electrode materials are exploited to fabricate an FASC device with a maximum working voltage of 1.6 V, and this device exhibits a high specific capacitance of 109.4 F cm-3 (328.3 mF cm-2) and excellent energy density of 36.0 mWh cm-3 (108.1 µWh cm-2). This work therefore provides a strategy for constructing all hierarchical core-shell heterostructured cathode and anode materials with ultrahigh capacity for the fabrication of next-generation wearable energy-storage devices.

Metal-Organic Framework Derived Spindle-like Carbon Incorporated α-Fe2O3 Grown on Carbon Nanotube Fiber as Anodes for High-Performance Wearable Asymmetric Supercapacitors.

Iron oxide (Fe2O3) has drawn much attention because of its high theoretical capacitance, wide operating potential window, low cost, natural abundance, and environmental friendliness. However, the inferior conductivity and insufficient ionic diffusion rate of a simple Fe2O3 electrode leading to the low specific capacitance and poor rate performance of supercapacitors have impeded its applications. In this work, we report a facile and cost-effective method to directly grow MIL-88-Fe metal-organic framework (MOF) derived spindle-like α-Fe2O3@C on oxidized carbon nanotube fiber (S-α-Fe2O3@C/OCNTF). The S-α-Fe2O3@C/OCNTF electrode is demonstrated with a high areal capacitance of 1232.4 mF/cm2 at a current density of 2 mA/cm2 and considerable rate capability with capacitance retention of 63% at a current density of 20 mA/cm2 and is well matched with the cathode of the Na-doped MnO2 nanosheets on CNTF (Na-MnO2 NSs/CNTF). The electrochemical test results show that the S-α-Fe2O3@C/OCNTF//Na-MnO2 NSs/CNTF asymmetric supercapacitors possess a high specific capacitance of 201.3 mF/cm2 and an exceptional energy density of 135.3 µWh/cm2. Thus, MIL-88-Fe MOF derived S-α-Fe2O3@C will be a promising anode for applications in next-generation wearable asymmetric supercapacitors.

All-Metal-Organic Framework-Derived Battery Materials on Carbon Nanotube Fibers for Wearable Energy-Storage Device.

The ever-increasing demands for portable and wearable electronics continue to drive the development of high-performance fiber-shaped energy-storage devices. Metal-organic frameworks (MOFs) with well-tunable structures and large surface areas hold great potential as precursors and templates to form porous battery materials. However, to date, there are no available reports about fabrication of wearable energy-storage devices on the utilization of all-MOF-derived battery materials directly grown on current collectors. Here, MOF-derived NiZnCoP nanosheet arrays and spindle-like α-Fe2O3 on carbon nanotube fibers are successfully fabricated with impressive electrochemical performance. Furthermore, the resulting all-solid-state fiber-shape aqueous rechargeable batteries take advantage of large specific surface area and abundant reaction sites of well-designed MOF-derived electrode materials to yield a remarkable capacity of 0.092 mAh cm-2 and admirable energy density of 30.61 mWh cm-3, as well as superior mechanical flexibility. Thus, this research may open up exciting opportunities for the development of new-generation wearable aqueous rechargeable batteries.

Rational Design of Hierarchical Titanium Nitride@Vanadium Pentoxide Core-Shell Heterostructure Fibrous Electrodes for High-Performance 1.6 V Nonpolarity Wearable Supercapacitors.

Extensive progress has been made in fiber-shaped asymmetric supercapacitors (FASCs) for portable and wearable electronics. However, positive and negative electrodes must be distinguished and low energy densities are a crucial challenge and thus limit their practical applications. This paper reports an efficient method to directly grow TiN nanowire arrays@V2O5 nanosheets core-shell heterostructures on carbon nanotube fibers as nonpolarity electrodes. Benefiting from their unique heterostructure, single electrodes possess high specific capacitances of 195.1 and 230.7 F cm-3 as positive and negative electrodes, respectively. Furthermore, all-solid-state nonpolarity FASC devices with a maximum voltage of 1.6 V were successfully fabricated. Our devices achieve an outstanding specific capacitance of 74.25 F cm-3 and a remarkable energy density of 26.42 mW h cm-3. More importantly, their electrochemical performance changed negligibly regardless of whether the charge-discharge process is in positive or negative direction, indicating excellent nonpolarity. Therefore, these high-performance nonpolarity FASCs pave the way for next-generation wearable energy storage devices.

Facile Synthesis of Na-Doped MnO2 Nanosheets on Carbon Nanotube Fibers for Ultrahigh-Energy-Density All-Solid-State Wearable Asymmetric Supercapacitors.

Flexible fiber-shaped supercapacitors hold promising potential in the area of portable and wearable electronics. Unfortunately, their general application is hindered by the restricted energy densities due to low operating voltage and small specific surface area. Herein, an all-solid-state fiber-shaped asymmetric supercapacitor (FASC) possessing ultrahigh energy density is reported, in which the positive electrode was designed as Na-doped MnO2 nanosheets on carbon nanotube fibers (CNTFs) and the negative electrode as MoS2 nanosheet-coated CNTFs. Owing to the excellent properties of the designed electrodes, our FASCs exhibit a large operating potential window (0-2.2 V), a remarkable specific capacitance (265.4 mF/cm2), as well as an ultrahigh energy density (178.4 µWh/cm2). Moreover, the devices are of outstanding mechanical flexibility.

Erratum: 3D Printing Fiber Electrodes for an All-Fiber Integrated Electronic Device via Hybridization of an Asymmetric Supercapacitor and a Temperature Sensor.

[This corrects the article DOI: 10.1002/advs.201801114.].

3D Printing Fiber Electrodes for an All-Fiber Integrated Electronic Device via Hybridization of an Asymmetric Supercapacitor and a Temperature Sensor.

Wearable fiber-shaped electronic devices have drawn abundant attention in scientific research fields, and tremendous efforts are dedicated to the development of various fiber-shaped devices that possess sufficient flexibility. However, most studies suffer from persistent limitations in fabrication cost, efficiency, the preparation procedure, and scalability that impede their practical application in flexible and wearable fields. In this study, a simple, low-cost 3D printing method capable of high manufacturing efficiency, scalability, and complexity capability to fabricate a fiber-shaped integrated device that combines printed fiber-shaped temperature sensors (FTSs) with printed fiber-shaped asymmetric supercapacitors (FASCs) is developed. The FASCs device can provide stable output power to FTSs. Moreover, the temperature responsivity of the integrated device is 1.95% °C-1.

In Situ Generation of Photosensitive Silver Halide for Improving the Conductivity of Electrically Conductive Adhesives.

Electrically conductive adhesives (ECAs) can be regarded as one of the most promising materials to replace tin/lead solder. However, relatively low conductivity seriously restricts their applications. In the present study, we develop an effective method to decrease the bulk electrical resistivity of ECAs. KI or KBr is added to replace the lubricant and silver oxide layers on silver flakes and to form photosensitive silver halide. After exposure to sunlight, silver halide can photodecompose into silver nanoparticles that will sinter and form metallic bonding between/among flakes during the curing process of ECAs, which would remarkably reduce the resistivity. The modified micro silver flakes play a crucial role in decreasing the electrical resistivity of the corresponding ECAs, exhibiting the lowest resistivity of 7.6 × 10-5 Ω·cm for 70 wt % loaded ECAs. The obtained ECAs can have wide applications in the electronics industry, where high conductance is required.