Hierarchically wood-derived integrated electrode with tunable superhydrophilic/superaerophobic surface for efficient urea electrolysis

Conferring surfaces with superhydrophilic/superaerophobic characteristics is desirable for synthesizing efficient gas reaction catalysts.However,complicated procedures,high costs,and poor interfaces hinder commercialization.Here,an integrated electrode with tunable wettability derived from a hierarchically porous wood scaffold was well designed for urea oxidation reaction(UOR).Interestingly,the outer surface of the wood lumen was optimized to the preferred wettability via stoichiometry to promote electrolyte permeation and gas escape.This catalyst exhibits outstanding activity and durability for UOR in alkaline media,requiring only a potential of 1.36 V(vs.RHE)to deliver 10 m A cm^(-2)and maintain its activity without significant decay for 60 h.These experiments and theoretical calculations demonstrate that the nickel(oxy)hydroxide layer formed through surface reconstruction of nickel nanoparticles improves the active sites and intrinsic activity.Moreover,the superwetting properties of the electrode promote mass transfer by guaranteeing substantial contact with the electrolyte and accelerating the separation of gaseous products during electrocatalysis.These findings provide the understanding needed to manipulate the surface wettability through rational design and fabrication of efficient electrocatalysts for gas-evolving processes.

Self-supporting NiFe LDH-MoS_(x) integrated electrode for highly efficient water splitting at the industrial electrolysis conditions

Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2) under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2) under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2) for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2) at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.

Hierarchical coral-like FeNi(OH)_x/Ni via mild corrosion of nickel as an integrated electrode for efficient overall water splitting

Efficient,stable,and noble‐metal‐free electrocatalysts for both the oxygen evolution reaction and the hydrogen evolution reaction are highly imperative for the realization of low‐cost commercial water‐splitting electrolyzers.Herein,a cost‐effective and ecofriendly strategy is reported to fabricate coral‐like FeNi(OH)x/Ni as a bifunctional electrocatalyst for overall water splitting in alkaline media.With the assistance of mild corrosion of Ni by Fe(NO3)3,in situ generated FeNi(OH)x nanosheets are intimately attached on metallic coral‐like Ni.Integration of these nanosheets with the electrodeposited coral‐like Ni skeleton and the supermacroporous Ni foam substrate forms a binder‐free hierarchical electrode,which is beneficial for exposing catalytic active sites,accelerating mass transport,and facilitating the release of gaseous species.In 1.0 mol L^-1 KOH solution,a symmetric electrolyzer constructed with FeNi(OH)x/Ni as both the anode and the cathode exhibits an excellent activity with an applied potential difference of 1.52 V at 10 mA cm^-2,which is superior to that of an asymmetric electrolyzer constructed with the state‐of‐the‐art RuO2‐PtC couple(applied potential difference of 1.55 V at 10 mA cm^-2).This work contributes a facile and reliable strategy for manufacturing affordable,practical,and promising water‐splitting devices.

Synergistic Coupling of Sulfide Electrolyte and Integrated 3D FeS_(2)Electrode Toward Long-Cycling All-Solid-State Lithium Batteries

FeS_(2)cathode is promising for all-solid-state lithium batteries due to its ultra-high capacity,low cost,and environmental friendliness.However,the poor performances,induced by limited electrode-electrolyte interface,severe volume expansion,and polysulfide shuttle,hinder the application of FeS_(2)in all-solid-state lithium batteries.Herein,an integrated 3D FeS_(2)electrode with full infiltration of Li6PS5Cl sulfide electrolytes is designed to address these challenges.Such a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes,but also effectively buffers the inner volume change of FeS_(2)and completely eliminates the polysulfide shuttle through direct solid-solid conversion of Li2S/S.Besides,the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths,endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction kinetics.Benefiting from these synergies,the integrated all-solid-state lithium battery exhibits the largest reversible capacity(667 mAh g^(-1)),best rate performance,and highest capacity retention of 82%over 500 cycles at 0.1 C compared to both a liquid battery and non-integrated all-solid-state lithium battery.The cycling performance is among the best reported for FeS_(2)-based all-solid-state lithium batteries.This work presents an innovative synergistic strategy for designing long-cycling high-energy all-solid-state lithium batteries,which can be readily applied to other battery systems,such as lithium-sulfur batteries.

Interface and energy band manipulation of Bi2O3-Bi2S3 electrode enabling advanced magnesium-ion storage

Rechargeable magnesium-ion(Mg-ion)batteries have attracted wide attention for energy storage.However,magnesium anode is still limited by the irreversible Mg plating/stripping procedure.Herein,a well-designed binary Bi_(2)O_(3)-Bi_(2)S_(3)(BO-BS)heterostructure is fulfilled by virtue of the cooperative interface and energy band engineering targeted fast Mg-ion storage.The built-in electronic field resulting from the asymmetrical electron distribution at the interface of electron-rich S center at Bi_(2)S_(3) side and electron-poor O center at Bi_(2)O_(3) side effectively accelerates the electrochemical reaction kinetics in the Mg-ion battery system.Moreover,the as-designed heterogenous interface also benefits to maintaining the electrode integrity.With these advantages,the BO-BS electrode displays a remarkable capacity of 150.36 mAh g^(−1) at 0.67 A g^(-1) and a superior cycling stability.This investigation would offer novel insights into the rational design of functional heterogenous electrode materials targeted the fast reaction kinetics for energy storage systems.

Enabling 2.4-V aqueous supercapacitors through the rational design of an integrated electrode of hollow vanadium trioxide/carbon nanospheres

Aqueous supercapacitors(SCs)exhibit several advantages,including high-power density,cycling durability,and safety;however,the shortage of low energy density inhibits their further application.Acquiring an excellent performance upon using simple strategies would be beneficial,but remains challenging.Here,an integrated electrode of hollow V_(2)O_(3)/carbon nanospheres(H-V_(2)O_(3)/C)was designed and synthesized for SCs.The introduction of carbon can increase the conductivity and stability,whereas the hollow structure endows H-V_(2)O_(3)/C with a high specific surface area and rapid transport of ions.Moreover,the H-V_(2)O_(3)/C integrated electrode can simultaneously work in both negative and positive potential windows.Benefiting from these advantages,the H-V_(2)O_(3)/C integrated electrode exhibits a specific capacitance as high as 708.6 F g^(-1) in a wide voltage window of-1.1-1.3 V.Furthermore,stemming from the multiple energy storage mechanisms,the aqueous integrated full SC device exhibits a wider potential window and higher energy density than the traditional(a)symmetric ones.Therefore,the proposed device delivers a wide voltage window of 2.4 V with an energy density of 96.8 W h kg^(-1) at a power density of 1204.6 W kg^(-1),as well as superior cycling stability.This study enlightens the design and preparation of electrode materials,opening up a possible approach for developing wide-voltage aqueous SCs.

Integrated Nanostructural Electrodes Based on Layered Double Hydroxides

Layered double hydroxides(LDHs), as a class of typical two-dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as electrode active materials has seen much progress in terms of structure designing, material synthesis, properties tailoring, and applications. In this review, we focus on the integrated nanostructural electrodes(INEs) construction using LDH materials, including pristine LDH-INEs, hybrid LDH-INEs, and LDH derivativeINEs, as well as the performance advantages and applications of LDH-INEs.Moreover, in the final section, the insights about challenges and prospective in this promising research field were concluded, especially in regulation of intrinsic activity and uncovering of structure–activity relationship, which would push forward the development of this fast-growing field.

Integrated Carbon Nanotubes Electrodes in Microfluidic Chip via MWPCVD

An on-chip electrochemical detector for microfluidic chips was described, based on integrated carbon nanotube （CNT） electrodes directly onto the chip substrate through microwave plasma chemical vapor deposition （MWPCVD）. The attractive performance of the integrated CNT electrodes was demonstrated for the amperometric detection of sucrose, glucose and D-fructose. The integrated CNT electrodes showed stronger electrocatalytic activity than gold electrodes.

Electro-spraying/spinning: A novel battery manufacturing technology

Lithium-ion battery(LIB) industry seems to have met its bottle neck in cutting down producing costs even though much efforts have been put into building a complete industrial chain. Actually, manufacturing methods can greatly affect the cost of battery production. Up to now, lithium ion battery producers still adopt manufacturing methods with cumbersome sub-components preparing processes and costly assembling procedures, which will undoubtedly elevate the producing cost. Herein, we propose a novel approach to directly assemble battery components(cathode, anode and separator) in an integrated way using electro-spraying and electro-spinning technologies. More importantly, this novel battery manufacturing method can produce LIBs in large scale, and the products show excellent mechanical strength, flexibility, thermal stability and electrolyte wettability. Additionally, the performance of the as-prepaed Li Fe PO_(4)||graphite full cell produced by this new method is comparable or even better than that produced by conventional manufacturing approach. In brief, this work provides a new promising technology to prepare LIBs with low cost and better performance.

Interfacial fusion-enhanced 11 μm-thick gel polymer electrolyte for high-performance lithium metal batteries

In the pursuit of ultrathin polymer electrolyte(<20 μm) for lithium metal batteries, achieving a balance between mechanical strength and interfacial stability is crucial for the longevity of the electrolytes.Herein, 11 μm-thick gel polymer electrolyte is designed via an integrated electrode/electrolyte structure supported by lithium metal anode. Benefiting from an exemplary superiority of excellent mechanical property, high ionic conductivity, and robust interfacial adhesion, the in-situ formed polymer electrolyte reinforced by titanosiloxane networks(ISPTS) embodies multifunctional roles of physical barrier, ionic carrier, and artificial protective layer at the interface. The potent interfacial interactions foster a seamless fusion of the electrode/electrolyte interfaces and enable continuous ion transport. Moreover, the built-in ISPTS electrolyte participates in the formation of gradient solid-electrolyte interphase(SEI) layer, which enhances the SEI's structural integrity against the strain induced by volume fluctuations of lithium anode.Consequently, the resultant 11 μm-thick ISPTS electrolyte enables lithium symmetric cells with cycling stability over 600 h and LiFePO_(4) cells with remarkable capacity retention of 96.6% after 800 cycles.This study provides a new avenue for designing ultrathin polymer electrolytes towards stable, safe,and high-energy–density lithium metal batteries.

Highly integrated sulfur cathodes with strong sulfur/high-strength binder interactions enabling durable high-loading lithium-sulfur batteries

The development of high-sulfur-loading Li-S batteries is a key prerequisite for their commercial applications.This requires to surmount the huge polarization,severe polysulfide shuttling and drastic volume change caused by electrode thickening.High-strength polar binders are ideal for constructing robust and long-life high-loading sulfur cathodes but show very weak interfacial interaction with non-polar sulfur materials.To address this issue,this work devises a highly integrated sulfur@polydopamine/highstrength binder composite cathodes,targeting long-lasting and high-sulfur-loading Li-S batteries.The super-adhesion polydopamine(PD)can form a uniform nano-coating over the graphene/sulfur(G-S)surface and provide strong affinity to the cross-linked polyacrylamide(c-PAM)binder,thus tightly integrating sulfur with the binder network and greatly boosting the overall mechanical strength/conductivity of the electrode.Moreover,the PD coating and c-PAM binder rich in polar groups can form two effective blockades against the effusion of soluble polysulfides.As such,the 4.5 mg cm−2 sulfur-loaded G-S@PD-c-PAM cathode achieves a capacity of 480 mAh g−1 after 300 cycles at 1 C,while maintaining a capacity of 396 mAh g−1 after 50 cycles at 0.2 C when the sulfur loading rises to 9.1 mg cm−2.This work provides a system-wide concept for constructing high-loading sulfur cathodes through integrated structural design.

A N-CoSe/CoSe_(2)-C@Cu hierarchical architecture as a current collector-integrated anode for potassium-ion batteries

The highly reversible insertion/extraction of large-radius K^+into electrode materials remains a tough goal,especially for con version-type materials.Herein,we design a current collector-integrated electrode(N-CoSe/CoSe_(2)-C@Cu) as an advanced anode for potassium-ion battery(PIBs).The conductive CoSe/CoSe_(2) heterojunction with rich Se vacancy defects,conductive sp^2 N-doped carbon layer,and the elastic copper foil matrix can greatly accelerate the electron transfer and enhance the structural stability.Consequently,the well-designed N-CoSe/CoSe_(2)-C@Cu current collector-integrated electrode displays enhanced potassium storage performance with regard to a high capacity(325.1 mAh·g^(-1) at 0.1 A·g^(-1) after 200cycles),an exceptional rate capability(223.5 mAh·g^(-1) at2000 mA·g^(-1)),and an extraordinary long-term cycle stability(a capacity fading of only 0.019% per cycle over1200 cycles at 2000 mA·g^(-1)).Impressively,ex situ scanning electron microscopy(SEM) characterizations prove that the elastic structure of copper foil is merged into the cleverly designed N-CoSe/CoSe_(2)-C@Cu heterostructure,which buffers the deformation of structure and volume and greatly promotes the cycle life during the potassium/depotassium process.

CuO nanoflowers/copper fiber felt integrated porous electrode for lithium-ion batteries

The structure of current collectors has significant effects on the performance of a lithium-ion battery(LIB).In this study,we use copper fiber felts made by multi-tooth cutting and high-temperature solid-phase sintering as the current collector for LIBs.An integrated porous electrode based on CuO nanoflowers/copper fiber felt is developed for the anode.Results suggest that the reversible capacity and cycle stability of this new anode are significantly improved,compared with the pristine bare-surface copper plate under the same condition of rate cycles.The new anode structure based on the copper-fiber felt with a porosity of 60%exhibits a higher performance with an initial specific capacity of 609.5 mAh g^(-1)and retains 486.1 mAh g^(-1)after 200 cycles at a current density of 0.5 C.The improved electrochemical performance of this electrode is attributed to its large surface area of CuO nanoflowers and porous structure of the copper fiber felt,due to enhanced contact between the active material of CuO nanoflowers and electrolyte.This pore-rich structure makes the electrolyte easy to permeate into the electrode,shortens the diffusion path of Li^(+),reduces the internal resistance and alleviates the volume expansion of the active material during the insertion and desertion processes of Li^(+).

Three-dimensional interconnected Ni（Fe）OxHy nanosheets on stainless steel mesh as a robust integrated oxygen evolution electrode

The development of an electrocatalyst based on abundant elements for the oxygen evolution reaction （OER） is important for water splitting associated with renewable energy sources. In this study, we develop an interconnected Ni（Fe）OxHy nanosheet array on a stainless steel mesh （SSNNi） as an integrated OER electrode, without using any polymer binder. Benefiting from the well- defined three-dimensional （3D） architecture with highly exposed surface area, intimate contact between the active species and conductive substrate improved electron and mass transport capacity, facilitated electrolyte penetration, and improved mechanical stability. The SSNNi electrode also has excellent OER performance, including low overpotential, a small Tafel slope, and long-term durability in the alkaline electrolyte, making it one of the most promising OER electrodes developed.

Wood-derived integrated air electrode with Co-N sites for rechargeable zinc-air batteries

The sluggish reaction kinetics in oxygen reduction reaction(ORR)is one of the bottlenecks in next generation energy conversion systems.The integrated design strategy based on simultaneously constructing active sites and forming porous carbon network will address this concern by facilitating charge exchange,mass transfer and electron transportation.In this article,a three-dimensional integrated air electrode(Co-N@ACS)containing Co-N sites and hierarchically porous carbon is fabricated via growth of Co-doped ZIF-8 in activated wood substrate and synchronous pyrolysis.The optimized integrated air electrodes exhibit ultrahigh ORR activity(E_(1/2)=0.86 V).Co-N sites provide outstanding ORR activity,and hierarchically porous structures facilitate oxygen diffusion and electrolyte penetration.Aqueous zinc-air battery assembled with Co-N@ACS possesses open-circuit voltage of 1.46 V,peak power density of 155 mW cm^(-2) and long-term stability of 540 cycles(180 h).Solid-state zinc-air battery assembled with Co-N@ACS shows open-circuit voltage up to 1.36 V and low charge-discharge voltage gap(0.8 V).This design strategy paves the way for the conversion of wood biomass to integrated air electrodes and catalytically active carbon for next generation energy storage and conversion devices.

Needle
tip effect promoted flexible electrochemical sensor for detecting chloride ions in food by in
situ deposited silver dendrimers

Salt plays a crucial role in food processing and consumption,and the rapid detection of chloride ions in food and feed has great significance for practical applications.In this work,Ag-based nanomaterials were deposited on the surface of a flexible integrated electrochemical sensor for the detection of Cl-in food.In order to enhance the detection performance,a unique needle-tip structure was formed by manipulating the electro-engraving process during the electrodeposition growth.Theoretical calculations and electrochemical investigations have demonstrated that the dendrimer’s rich tip structure significantly enhanced its electrochemical performance.A sensitive and flexible integrated electrochemical sensor was creatively developed for the detection of Cl-using needle
tip effect-promoted Ag micro dendrimers.The sensor achieved quantitative detection of Cl-over a dynamic range of 10.0μM–100.0 mM,with a low limit of detection of 0.148μM.The flexible electrochemical sensor proposed in this work exhibited good repeatability,selectivity and recoveries in real food samples.