Zinc–Bromine Rechargeable Batteries:From Device Configuration,Electrochemistry,Material to Performance Evaluation

Zinc–bromine rechargeable batteries(ZBRBs)are one of the most powerful candidates for next-generation energy storage due to their potentially lower material cost,deep discharge capability,non-flammable electrolytes,relatively long lifetime and good reversibility.However,many opportunities remain to improve the efficiency and stability of these batteries for long-life operation.Here,we discuss the device configurations,working mechanisms and performance evaluation of ZBRBs.Both non-flow(static)and flow-type cells are highlighted in detail in this review.The fundamental electrochemical aspects,including the key challenges and promising solutions,are discussed,with particular attention paid to zinc and bromine half-cells,as their performance plays a critical role in determining the electrochemical performance of the battery system.The following sections examine the key performance metrics of ZBRBs and assessment methods using various ex situ and in situ/operando techniques.The review concludes with insights into future developments and prospects for high-performance ZBRBs.

可再生燃料的光催化和光电催化合成专栏

A renewable energy supply is an integral part of a sustainable society.The most abundant and widespread renewable energy source available on the earth,i.e.,sunlight,is intermittent and has a low energy density.This makes an economical and efficient technology to convert and store the solar energy necessary in order to utilise it on our path towards a low carbon economy.Photocatalysis and photo‐electrocatalysis can in principle store renewable solar energy into chemical bonds by diverse chemical processes,including water splitting to H_(2),nitrogen reduction to ammonia,CO_(2) reduction to chemicals and others.These chemical processes physically involve charge generation,charge separation and transfer,chemically include two half reactions and generally share the very sluggish water oxidation half reaction.The persistent kinetic challenges of these complex photophysical and photochemical processes have kept solar to fuel conversion efficiency as very moderate.

Yolk-shell Si/C composites with multiple Si nanoparticles encapsulated into double carbon shells as lithium-ion battery anodes

The conceptual design of yolk-shell structured Si/C composites is considered to be an effective way to improve the recyclability and conductivity of Si-based anode materials. Herein, a new type of yolk-shell structured Si/C composite (denoted as TSC-PDA-B) has been intelligently designed by rational engineering and precise control. In the novel structure, the multiple Si nanoparticles with small size are successfully encapsulated into the porous carbon shells with double layers benefiting from the strong etching effect of HF. The TSC-PDA-B product prepared is evaluated as anode materials for lithium-ion batteries (LIBs). The TSC-PDA-B product exhibits an excellent lithium storage performance with a high initial capacity of 2108 mAh g^-1 at a current density of 100 mA g^-1 and superior cycling performance of 1113 mAh g^-1 over 200 cycles. The enhancement of lithium storage performance may be attributed to the construction of hybrid structure including small Si nanoparticles, high surface area, and double carbon shells, which can not only increase electrical conductiv让y and intimate electrical contact with Si nanoparticles, but also provide built-in buffer voids for Si nanoparticles to expand freely without damaging the carbon layer. The present findings can provide some scientific insights into the design and the application of advanced Si-based anode materials in energy storage fields.

Solar energy conversion on g-C3N4 photocatalyst:Light harvesting,charge separation,and surface kinetics

Photocatalysis. which utilizes solar energy to trigger chemical reactions, is one of the most desirable solar-energy-conversion approaches. Graphitic carbon nitride （g-C3N4）. as an attractive metal-free photocatalyst, has drawn worldwide research interest in the area of solar energy conversion due to its easy synthesis, earth-abundant nature, physicochemical stability and visible-light-responsive properties. Over the past ten years, g-C3N4 based photocatalysts have experienced intensive exploration, and great progress has been achieved. However, the solar conversion efficiency is still far from industrial applications due to the wide bandgap, severe charge recombination, and lack of surface active sites. Many strategies have been proposed to enhance the light absorption, reduce the recombination of charge carriers and accelerate the surface kinetics. This work makes a crucial review about the main contributions of various strategies to the light harvesting, charge separation and surface kinetics of g-C3N4 photocatalyst. Furthermore, the evaluation measurements for the enhanced light harvesting, reduced charge recombination and accelerated surface kinetics will be discussed. In addition, this review proposes future trends to enhance the photocatalytic performance of g-C3N4 photocatalyst for the solar energy conversion.

Separator coatings as efficient physical and chemical hosts of polysulfides for high-sulfur-loaded rechargeable lithium–sulfur batteries

Lithium-sulfur batteries(LSBs)are promising alternative energy storage devices to the commercial lithium-ion batteries.However,the LSBs have several limitations including the low electronic conductivity of sulfur(5×10^-30S cm^-1),associated lithium polysulfides(PSs),and their migration from the cathode to the anode.In this study,a separator coated with a Ketjen black(KB)/Nafion composite was used in an LSB with a sulfur loading up to 7.88 mg cm^-2to mitigate the PS migration.A minimum specific capacity(Cs)loss of 0.06%was obtained at 0.2 C-rate at a high sulfur loading of 4.39 mg cm^-2.Furthermore,an initial areal capacity up to 6.70 mAh cm^-2 was obtained at a sulfur loading of 7.88 mg cm^-2.The low Cs loss and high areal capacity associated with the high sulfur loading are attributed to the large surface area of the KB and sulfonate group(SO3^-)of Nafion,respectively,which could physically and chemically trap the PSs.

Electrochemical Surface Restructuring of Phosphorus-Doped Carbon@MoP Electrocatalysts for Hydrogen Evolution

The hydrogen evolution reaction(HER) through electrocatalysis is promising for the production of clean hydrogen fuel. However,designing the structure of catalysts,controlling their electronic properties,and manipulating their catalytic sites are a significant challenge in this field. Here,we propose an electrochemical surface restructuring strategy to design synergistically interactive phosphorus-doped carbon@MoP electrocatalysts for the HER. A simple electrochemical cycling method is developed to tune the thickness of the carbon layers that cover on MoP core,which significantly influences HER performance. Experimental investigations and theoretical calculations indicate that the inactive surface carbon layers can be removed through electrochemical cycling,leading to a close bond between the MoP and a few layers of coated graphene. The electronsdonated by the MoP core enhance the adhesion and electronegativity of the carbon layers;the negatively charged carbon layers act as an active surface. The electrochemically induced optimization of the surface/interface electronic structures in the electrocatalysts significantly promotes the HER. Using this strategy endows the catalyst with excellent activity in terms of the HER in both acidic and alkaline environments(current density of 10 mA cm^(-2) at low overpotentials,of 68 mV in 0.5 M H_(2)SO_(4) and 67 mV in 1.0 M KOH).

高效光解水光电极设计的研究进展（英文）

光电化学(PEC)分解水过程被认为是由太阳能制氢的一个有前景的路径,PEC的关键在于高效电极的设计.最近的十多年里有关材料设计、共催化剂研究和电极制造取得了重大进展,但仍存在一些关键挑战尚未解决,包括迫切所需的转化效率.作为PEC过程的三个关键步骤:光采集、电荷转移和表面反应,发生在很广的时间尺度(10^(–12)–10~0 s)内,如何组织好这一连串的步骤以促进各步骤间的无缝协作从而实现高效的PEC过程显得非常重要.基于高效稳定PEC光电极设计的研究进展,本文重点综述了整体考虑的三个主要标准,总结了一些基本原则和潜在的策略,尤其讨论了挑战与前景.

All-Climate Aluminum-Ion Batteries Based on Binder-Free MOF-Derived FeS_(2)@C/CNT Cathode

Aluminum-ion batteries(AIBs)are promising next-generation batteries systems because of their features of low cost and abundant aluminum resource.However,the inferior rate capacity and poor all-climate performance,especially the decayed capacity under low temperature,are still critical challenges toward high-specific-capacity AIBs.Herein,we report a binder-free and freestanding metal-organic framework-derived FeS_(2)@C/carbon nanotube(FeS_(2)@C/CNT)as a novel all-climate cathode in AIBs working under a wide temperature window between−25 and 50℃ with exceptional flexibility.The resultant cathode not only drastically suppresses the side reaction and volu-metric expansion with high capacity and long-term stability but also greatly enhances the kinetic process in AIBs with remarkable rate capacity(above 151 mAh g^(−1) at 2 A g^(−1))at room temperature.More importantly,to break the bottleneck of the inherently low capacity in graphitic material-based all-climate AIBs,the new hierarchical conductive composite FeS_(2)@C/CNT highly promotes the all-climate performance and delivers as high as 117 mAh g^(−1) capacity even under−25°C.The well-designed metal sulfide electrode with remarkable performance paves a new way toward all-climate and flexible AIBs.

Bismuth based photoelectrodes for solar water splitting

Photoelectrochemical water splitting is a sustainable path to generate valuable hydrogen using sunlight and water as the only inputs.Despite significant efforts to date,it is still a challenge to achieve photoelectrode with superior performance and long-term stability.Many bismuth-based semiconductor materials have demonstrated excellent visible light harvesting capability and suitable band edge for water splitting.Herein,we summarized the latest studies conducted on bismuth-based photoelectrodes for photoelectrochemical water splitting.Specifically,photoelectrochemical properties of copper bismuth oxide(CuBi_(2)O_(4)),bismuth ferrites(BiFeO_(3),Bi_(2)Fe_(4)O_(9)),bismuth vanadate(BiVO_(4)),bismuth tungstate(Bi_(2)WO_(6)),bismuth molybdate(Bi_(2)MoO_(6))and bismuth oxyhalids(BiOX,X=I,Cl,Br)are presented.Strategies to achieve high stability and photolectrochemical performance were discussed in the aspects of nanostructure formation,heterostructure assembly,practical defect engineering,preferential facet growth and oxygen evolution catalyst incorporation.

Ligand engineering of perovskite quantum dots for efficient and stable solar cells

Lead halide perovskite quantum dots(PQDs) have recently emerged as promising light absorbers for photovoltaic application due to their extraordinary optoelectronic properties. Surface ligands are of utmost importance for the colloidal stability and property tuning of PQDs, while their highly dynamic binding nature not only impedes further efficiency improvement of PQD-based solar cells but also induces intrinsic instability. Tremendous efforts have been made in ligand engineering with good hopes to solve such challenging issues in the past few years. In this review, we first present a fundamental understanding of the role of surface ligands in PQDs, followed by a brief discussion and classification of various ligands that have the potential for improving the electronic coupling and stability of PQD solids. We then provide a critical overview of recent advances in ligand engineering including the strategies of in-situ ligand engineering, postsynthesis/-deposition ligand-exchange, and interfacial engineering, and discuss their impacts on changing the efficiency and stability of perovskite QD solar cells(QDSCs). Finally, we give our perspectives on the future directions of ligand engineering towards more efficient and stable perovskite QDSCs.

Recent Advances in Printed Thin-Film Batteries

The rapidly increasing demand for wearable electronic devices has motivated research in low-cost and flexible printed batteries with diverse form factors and architectures.In the past,technological achieve-ments in the field have been emphasized,overlooking the industrial and market requirements.However,different applications require different battery chemistries and formats,that greatly impacts the manu-facturing process and competition landscape.These chemistries and formats should therefore be selected carefully to maximize the chances for commercial success.As some of these technologies are starting to be marketed for portable electronics,there is a pressing need to evaluate different printing technologies and compare them in terms of the processing constraints and product requirements of specific electronic devices.By evaluating the intrinsic strengths and current limitations of printed battery technologies,development pathways can be prioritized,and potential bottlenecks can be overcome to accelerate the path to market.

Nitrogen incorporated oxygen vacancy enriched MnCo_(2)O_(x)/BiVO_(4) photoanodes for efficient and stable photoelectrochemical water splitting

Oxygen vacancies in oxygen evolution cocatalysts(OECs)can significantly improve the photoelectrochemical(PEC)water splitting performance of photoanodes.However,OECs with abundant oxygen vacancies have a poor stability when exposing to the highly-oxidizing photogenerated holes.Herein,we partly fill oxygen vacancies in a MnCo_(2)O_(x) OEC with N atoms by a combined electrodeposition and sol-gel method,which dramatically improves both photocurrent density and stability of a BiVO_(4) photoanode.The optimized N filled oxygen vacancy-rich MnCo_(2)O_(x)/BiVO_(4) photoanode(3 at.%of N)exhibits an outstanding photocurrent density of 6.5 mA·cm^(-2) at 1.23 VRHE under AM 1.5 G illumination(100 mW·cm^(-2)),and an excellent stability of over 150 h.Systematic characterizations and theoretical calculations demonstrate that N atoms stabilize the defect structure and modulate the surface electron distribution,which significantly enhances the stability and further increases the photocurrent density.Meanwhile,other heteroatoms such as carbon,phosphorus,and sulfur are confirmed to have similar effects on improving PEC water splitting performance of photoanodes.

Organic ligand nanoarchitectonics for BiVO_(4) photoanodes surface passivation and cocatalyst grafting

Bismuth vanadate(BiVO_(4))is a promising photoanode material for efficient photoelectrochemical(PEC)water splitting,whereas its performance is inhibited by detrimental surface states.To solve the problem,herein,a low-cost organic molecule 1,3,5-benzenetricarboxylic acid(BTC)is selected for surface passivation of BiVO_(4) photoanodes(BVOs),which also provides bonding sites for Co^(2+)to anchor,resulting in a Co-BTC-BVO photoanode.Owing to its strong coordination with metal ions,BTC not only passivates surface states of BVO,but also provides bonding between BVO and catalytic active sites(Co^(2+))to form a molecular cocatalyst.Computational study and interfacial charge kinetic investigation reveal that chemical bonding formed at the interface greatly suppresses charge recombination and accelerates charge transfer.The obtained Co-BTC-BVO photoanode exhibits a photocurrent density of 4.82 mA/cm^(2) at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.22 VRHE under AM 1.5 G illumination,which ranks among the best photoanodes coupled with Co-based cocatalysts.This work presents a novel selection of passivation layers and emphasizes the significance of interfacial chemical bonding for the construction of efficient photoanodes.

Recent progress in perovskite solar cells:material science

Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency.In light of the rapid development of perovskite materials and devices,a systematic survey on the latest advancements covering a broad range of related work is urgently needed.This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective.The discussed topics include the devices based on different type of perovskites(organic-inorganic hybrid,all-inorganic,and lead-free perovskite and perovskite quantum dots),the properties of perovskite defects,different type of charge transport materials(organic,polymeric,and inorganic hole transport materials and inorganic and organic electron transport materials),counter electrodes,and interfacial materials used to improve the efficiency and stability of devices.Most discussions focus on the key progresses reported within the recent five years.Meanwhile,the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.

靶向钝化与界面载流子动力学优化以提高无空穴传输层的窄带隙钙钛矿太阳电池的效率和稳定性

窄带隙锡-铅混合钙钛矿太阳电池(PSCs)的效率有望接近Shockley-Queisser极限,然而,易氧化的亚锡离子Sn^(2+)以及载流子传输层/钙钛矿未优化的界面接触会导致严重的界面电荷复合和器件性能下降,这在很大程度上阻碍了锡-铅混合钙钛矿太阳电池的实际应用,本文通过在钙钛矿中掺入少量有机膦酸咔唑分子,成功地制备了无空穴传输层锡-铅混合钙钛矿太阳电池.相对于Pb^(2+),有机磷酸咔唑分子在晶界处和晶体表面与Sn^(2+)离子有更强的化学配位作用,从而有效抑制Sn^(2+)的氧化,钝化缺陷并抑制非辐射复合。在移除空穴传输层的情况下,此类有机膦酸咔唑分子靶向修饰作用可有效增强内建电场(~100mV),优化透明导电基底与钙钛矿层的能级排列,从而加速光生电荷分离,促进界面空穴抽取和传输.最终,无空穴传输层的锡-铅混合钙钛矿太阳电池获得最高20.21%的光电转换效率,开路电压高达0.87V,同时实现了超过2400小时的长期稳定性。

Understanding the roles of carbon in carbon/g-C_(3)N_(4)based photocatalysts for H2 evolution

Coupling graphitic carbon nitride(CN)with carbonaceous materials is an effective strategy to improve photocatalytic performance,but the contributions of carbonaceous materials are not fully understood.Herein,a new type of carbon/CN(CCN)complex photocatalyst is synthesized with a 6-fold enhancement of H2 evolution rate compared to that of pristine CN.The role of carbon in photocatalytic H2 evolution reaction is systemically studied and it is experimentally and theoretically revealed that carbon mainly contributes to the improved capability of exciton dissociation and enhanced electric conductivity for charge transfer,leading to an increased population of photo-carriers for photocatalytic reactions.Interestingly,the enhanced light absorption originated from carbon barely generates charge carriers for H2 evolution activity.These new findings will inspire the rational design of carbon-based photocatalysts for efficient solar fuel production.

Mesoporous MnO_(2)nanosheets for efficient electrocatalytic nitrogen reduction via high spin polarization induced by oxygen vacancy

The electrochemical N_(2)reduction reaction(NRR)represents a green and sustainable route for NH_(3)synthesis under ambient conditions.However,the mechanism of N_(2)activation in the electrocatalytic NRR remains unclear.Herein,we found that the high spin state Mn^(3+)-Mn^(3+)pairs induced by oxygen vacancy in MnO_(2)nanosheets greatly enhance the catalytic activities.The strong electron transfer between d orbital of Mn and orbital of N2 forces the N_(2)to be of radical nature,which activates the hydrogenation process and weakens the N≡N bond.Based on the density functional theory(DFT)calculation results,we precisely designed mesoporous MnO_(2)nanosheets with rich oxygen vacancies via using methyltriphenylphosphonium bromide(MPB)to induce more Mn^(3+)-Mn^(3+)pairs(Mn^(3-3)-MnO_(2)),which can achieve a fairly high ammonia yield of up to 147.2μg·h^(−1)·mgcat−1.at−0.75 V vs.reversible hydrogen electrode(RHE)and a high Faradaic efficiency(FE)of 11%.Furthermore,these mesoporous MnO_(2)nanosheets exhibit the superior durability with negligible changes in both NH3 yield and FE after a consecutive 6-recycle test and the current density electrolyzed over a 24-hour period.Our findings offer an approach to designing highly active transition metal catalysts for electrocatalytic nitrogen reduction.

Reducing the vacancies associated with ferroelectric polarization to promote photocatalytic overall water splitting

Ferroelectric materials hold great promise in photocatalytic water splitting because their built-in electric field induced by the depolarization field can fulfill the separation of photogenerated carriers.However,a number of intrinsic charged vacancy defects are simultaneously generated to screen the depolarized field for stabilizing the crystal structure,always resulting in severe recombination of photogenerated carriers and thus poor overall water splitting activity.Herein,we proposed a strategy to promote the separation and transport of photogenerated carriers of ferroelectric photocatalysts by adjusting the ferroelectric polarization and altering the coordination environment of elements to reduce the defect concentration.Specifically,we prepared a series of Ta-doped PbTiO_(3)with low Pb(V_(Pb))and O(V_(O))vacancy concentrations by reducing the polarization intensity and strengthening the Pb–O interaction.The Ta-doped PbTiO_(3)shows efficient charge separation and greatly enhanced photocatalytic overall water splitting activity with the assistance of cocatalyst.This work highlights the importance of regulating ferroelectric polarization and vacancy defect concentration by the doping strategy in charge separation for photocatalytic water splitting.