摘要：Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy *** recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power ***,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little ***,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical *** PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics *** result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active ***,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the *** is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed *** addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel *** fully observable physical information of the digitalized cells provides strong support to the related analysis.

摘要：将甲烷直接转化为燃料和高附加值化学品引起了越来越多的研究兴趣,然而由于甲烷的化学惰性,实现这一过程仍然是一个巨大的挑战.本文设计了12种单原子合金催化剂(SAAs)应用于甲烷的活化,利用密度泛函理论(DFT)计算和微观动力学模拟筛选出对甲烷C–H键解离具有优异催化活性的单原子合金,并在此基础上进一步研究了甲烷选择性氧化制甲醇的机理.计算结果表明,惰性金属Ag、Au和Cu基底中掺杂Ir单原子具有更高的甲烷解离活性,这主要源于甲烷C–H键与Ir原子投影d轨道之间的相互作用.在引入分子氧之后,我们提出了甲烷选择性氧化制甲醇的三种反应机理.通过DFT计算确定了3条途径的完整反应网络,同时微观动力学模拟揭示了实际反应条件下每种SAA表面上反应物种覆盖度的变化.表面覆盖度分析表明,在所有的温度范围内,Ir1/Ag表面都有利于氧化反应,而Ir1/Au和Ir1/Cu只在有限的温度区间内有利于该氧化过程,表明Ir1/Ag单原子合金是甲烷选择性氧化制甲醇反应中非常有效的单原子合金催化剂.

摘要：Coupled with anionic and cationic redox chemistry,Li-rich/excess cathode materials are prospective high-energy-density candidates for the next-generation Li-ion ***,irreversible lattice oxygen loss would exacerbate irreversible transition metal migration,resulting in a drastic voltage decay and capacity ***,a metastable layered Li-excess cathode material,T2-type Li_(0.72)[Li_(0.12)Ni_(0.36)Mn_(0.52)]O_(2),was developed,in which both oxygen stacking arrangement and Li coordination environment fundamentally differ from that in conventional O3-type layered *** means of the reversible Li migration processes and structural evolutions,not only can voltage decay be effectively restrained,but also excellent capacity retention can be achieved upon long-term ***,irreversible/reversible anionic/cationic redox activities have been well assigned and quantified by various in/ex-situ spectroscopic techniques,further clarifying the charge compensation mechanism associated with(de)*** findings of the novel T2 structure with the enhanced anionic redox stability will provide a new scope for the development of high-energy-density Li-rich cathode materials.

摘要：As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively ***,safety issues and undesired lithium dendrite growth hinder its *** application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium *** oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent ***,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical *** this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in *** PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium *** Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.

摘要：Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and energy ***,the construction of a step-scheme heterostructure system(hereafter called the S-scheme)has received widespread attention in the photocatalytic field due to its ability to achieve efficient photogenerated carrier separation and obtain strong photo-redox ***,a novel S-scheme heterojunction system consisting of 2D O-doped g-C_(3)N_(4)(OCN)nanosheets and 3D N-doped Nb_(2)O_(5)/C(N-NBO/C)nanoflowers is constructed via ultrasonication and vigorous agitation technique followed by heat treatment for the photocatalytic degradation of Rhodamine B(RhB).Detailed characterization and decomposition behaviour of RhB showed that the fabricated material shows excellent photocatalytic efficiency and stability towards RhB photodegradation under visible-light *** enhanced performance could be attributed to the following factors:fast charge transfer,highly-efficient charge separation,extended lifetime of photoinduced charge carriers,and the high redox capability of the photoinduced charges in the S-scheme *** trapping experiment conditions and electron paramagnetic resonance provide clear evidence of the S-scheme photogenerated charge transfer path,meanwhile,the RhB mineralization degradation pathway was also investigated using *** study presents an approach to constructing Nb_(2)O_(5)-based S-scheme heterojunctions for photocatalytic applications.