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.

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.

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.

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.

合理设计空心V_(2)O_(3)/C集成电极赋予水系超级电容器2.4V电压窗口

水系超级电容器具有能量密度高,循环稳定性好,安全性高等优势,但低能量密度阻碍了其进一步应用.通过一种简单有效的方法得到具有高能量密度和宽电压的水系超级电容器依旧面临挑战.本工作设计了一种三氧化二钒/碳纳米空心球(H-V_(2)O_(3)/C)电极,并将其应用于水系超级电容器.碳的引入可以提高材料的导电性和稳定性,同时空心结构有利于提高电化学活性面积,提供快速的离子传输通道.此外,这种集成电极可同时工作于正极和负极电压窗口.因此,H-V_(2)O_(3)/C集成电极在-1.1–1.3 V的电压窗口下具有708.6 F g^(-1)的比容量.基于其多重储能机制,得到的水系对称超级电容器比传统的(非)对称超级电容器具有更高的电压窗口和能量密度.在2.4 V的宽电压下工作,当功率密度为1204.6 W kg^(-1)时具有96.8 W h kg^(-1)的高能量密度,同时具有优良的循环稳定性.本研究对电极材料的设计和制备具有一定的启发意义,为开发宽电压水系超级电容器开辟了一条新途径.