Development of advanced anion exchange membrane from the view of the performance of water electrolysis cell

Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.

Recent advances and future prospects on Ni_(3)S_(2)-Based electrocatalysts for efficient alkaline water electrolysis

Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.

Porous Nickel-Molybdenum Phosphide Alloy Electrodes for Alkaline Hydrogen Evolution Reaction at the High-Current Density

Alkaline water electrolysis is a practical route for large-scale green hydrogen production to assist decarbonization,whereby carbon dioxide emissions are limited.However,the use of this process in hydrogen evolution reaction(HER)is hampered by the alkaline solution,which leads to slow H_(2)O dissociation kinetics,especially when nickel–molybdenum(NiMo)alloy catalysts are utilized;thus,an improvement of this approach for effective HER activity is desirable.In this work,a porous phosphide NiMo-based(NiMoP)alloy electrode catalyst was engineered using a multistep electrodeposition method.Various experiments,combined with theoretical calculations,confirmed that the phosphide incorporation in the NiMo alloys promoted alkaline HER performance at a high current density of 1000 mA cm^(−2)with the potential−0.191 V.The evaluation of the effect of electrodeposition current density on HER performance revealed that the P content indeed positively impacted the accompanying alkaline HER performance,attributable to phosphide contribution in the electron reconstruction.Density functional theory(DFT)calculations demonstrated that the P atom promoted the loss of Mo electrons and hindered Ni from gaining electrons.This charge reconstruction allowed the optimization of the H^(*)adsorption,contributing to a stronger H_(2)O adsorption and encouraging H-OH^(*)bond breakage.Our current approach may provide the possibility of designing high-performance alkaline HER electrodes at high current density.

腹腔镜和开腹胆囊癌根治性切除术近期疗效及远期预后的比较

目的比较腹腔镜和开腹胆囊癌根治术的近期临床疗效及远期预后。方法回顾性分析2010年1月至2020年12月于浙江省人民医院肝胆胰外科接受胆囊癌根治术的133例胆囊癌患者的临床及术后随访资料。其中80例完成腹腔镜胆囊癌根治术(腹腔镜组),男性23例,女性57例,年龄[M(IQR)]66.0(12.8)岁(范围:28.0~82.0岁);53例完成开腹胆囊癌根治术(开腹组),男性8例,女性45例,年龄63.0(6.0)岁(范围:45.0~80.0岁)。腹腔镜组与开腹组在年龄、性别、体重指数、术前白蛋白、术前总胆红素、N分期、脉管侵犯、神经侵犯及肿瘤分化的差异均无统计学意义(P值均>0.05),而术前CA19-9(Z=-2.955,P=0.003)、术前ALT水平(Z=-2.801,P=0.031)、T分期分布(χ^(2)=19.110,P=0.007)的差异均有统计学意义。定量资料的比较采用非参数检验,分类资料的比较采用χ^(2)检验或Fisher确切概率法。结果两组患者在手术时间、淋巴结清扫数目、阳性淋巴结数目、术中胆囊破裂,术后胆瘘、腹腔出血、腹腔感染发生率,术后30 d和90 d病死率、切口种植及术后腹腔转移方面的差异均无统计学意义(P值均>0.05);腹腔镜组术中出血量[100.0(200.0)ml比400.0(250.0)ml](Z=-5.260,P<0.01)、引流管留置时间[6.0(3.8)d比7.0(4.0)d](Z=-3.351,P=0.001)及术后住院时间[8.0(5.0)d比14.0(7.5)d](Z=-6.079,P<0.01)优于开腹组。腹腔镜组1、3年总体生存率分别为63.6%、49.6%,开腹组1、3年总体生存率分别为37.7%、12.9%,差异有统计学意义(P<0.01);腹腔镜组1、3年无进展生存率分别为79.4%、54.1%,开腹组1、3年无进展生存率分别为55.7%、37.6%,差异有统计学意义(P<0.01)。对T1b~T2期及T3期胆囊癌进行亚组分析,结果显示,两组术后总体生存率及无进展生存率的差异均无统计学意义(P值均>0.05)。结论腹腔镜胆囊癌根治术可取得与开腹手术类似的近期临床结局和长期预后,且具有手术创伤小及术后恢复快的优势。

The effect of electrolyte additives on the rate performance of hard carbon anode at low temperature for lithium-ion capacitor

Lithium-ion capacitor(LIC),which combines the advantages of lithium-ion battery(LIB)and electrical double layer capacitor(EDLC),has a rapid development during last decade,however,the poor low temperature performance still limits its application.In this paper,three electrolyte additives including vinylene carbonate(VC),fluoroethylene carbonate(FEC)and 1,3,2-dioxathiolane 2,2-dioxide(DTD)have been utilized and their effects on the rate performance of hard carbon(HC)anode of LIC at various temperatures ranging from 25℃ to-40℃ have been well evaluated.The cell containing FEC shows the best rate performance at various temperatures and has the charge and discharge capability even at-40℃.For HC anode,the charge transfer impedance(R_(CT))increases exponentially at low temperature,while the equivalent series resistance(Rs)and the impedance of solid electrolyte interface(SEI)increase relatively few.At low temperatures,the effect of FEC may be mainly reflected in its effect on the charge transfer process.

Constructing an unbalanced structure toward high working voltage for improving energy density of non-aqueous carbon-based electrochemical capacitors

The energy density of non-aqueous carbon-based electrochemical capacitors(cEC)is mainly determined by the specific capacitance and operational voltage range.In this study,we propose to construct an unbalanced structure to make full use of stable voltage range for improving energy density.The stable voltage range is firstly carefully explored using cyclic voltammetry.Then an unbalanced carbon-based electrochemical capacitor(ucEC)is constructed with an optimized positive electrode to negative electrode weight ratio and voltage range.Its electrochemical performance is comprehensively investigated,including energy density,power density as well as cycle life.The ucEC is capable to deliver an improved energy density up to 64.9 Wh/kg(1.4 times as high as a general cEC)without sacrificing the power density and cycle life.The electrode properties after cycling are also analyzed,illustrating the change of electrode potential caused by unbalanced structure.The proposed structure demonstrates a great potential for improving the energy density at little cost of electrode design and cell configuration.

Effect of surface oxidation on the interfacial and mechanical properties in graphite/epoxy composites composite bipolar plates

Epoxy resin-reinforced graphite composites have found extensive application as bipolar plates in fuel cells for stationary power supplies,valued for their lightweight nature and exceptional durability.To enhance the interfacial properties between graphite and epoxy resin(EP),surface oxidation of graphite was carried out using diverse functional groups.Experimental assessments illustrated that the composites with graphite oxide resulted in heightened mechanical strength and toughness compared to pristine graphite,which could be attributed to the excellent interface connection.Moreover,these composites displayed remarkable conductivity while simultaneously retaining their mechanical attributes.Furthermore,molecular dynamics simulations outcomes unveiled that the inclusion of oxygen-containing functional groups on the graphite surface augmented the interfacial energy with EP,and the interface morphology between graphite and resin exhibited heightened stability throughout the stretching process.This simple and effective technique presents opportunities for improving composites interfaces,enabling high load transfer efficiency,and opens up a potential path for developing strong and tough composite bipolar plates for fuel cells.