Predicting power conversion efficiency of binary organic solar cells based on Y6 acceptor by machine learning

Organic solar cells(OSCs)are a promising photovoltaic technology for practical applications.However,the design and synthesis of donor materials molecules based on traditional experimental trial-anderror methods are often complex and expensive in terms of money and time.Machine learning(ML)can effectively learn from data sets and build reliable models to predict the performance of materials with reasonable accuracy.Y6 has become the landmark high-performance OSC acceptor material.We collected the power conversion efficiency(PCE)of small molecular donors and polymer donors based on the Y6 acceptor and calculated their molecule structure descriptors.Then we used six types of algorithms to develop models and compare the predictive performance with the coefficient of determination(R^(2))and Pearson correlation coefficient(r)as the metrics.Among them,decision tree-based algorithms showed excellent predictive capability,especially the Gradient Boosting Regression Tree(GBRT)models based on small molecular donors and polymer donors exhibited that the values of R2are 0.84 and 0.69 for the testing set,respectively.Our work provides a strategy to predict PCEs rapidly,and discovers the influence of the descriptors,thereby being expected to screen high-performance donor material molecules.

物理化学课程思政教学设计与实施——以“界面现象”为例

课程思政是落实立德树人根本任务的重要举措。物理化学课程是理工科类专业基础必修课程。本文结合物理化学课程教学面临的问题,采用将知识学习与思政教育有机融合的教学设计理念,并以“界面现象”内容的教学为例,充分挖掘了与界面现象相关的思政素材,并阐述了将知识线与思政线“双线融合”的教学设计思路和教学实施过程,以期为物理化学教师提供整体的课程思政教学设计思路和实例。

Li-air batteries:air stability of lithium metal anodes

Aprotic rechargeable lithium-air batteries(LABs)with an ultrahigh theoretical energy density(3,500 Wh kg^(-1))are known as the‘holy grail’of energy storage systems and could replace Li-ion batteries as the next-generation high-capacity batteries if a practical device could be realized.However,only a few researches focus on the battery performance and reactions in the ambient air environment,which is a major obstacle to promote the practical application of LABs.Here,we have summarized the recent research progress on LABs,especially with respect to the Li metal anodes.The chemical and electrochemical deteriorations of the Li metal anode under the ambient air are discussed in detail,and the parasitic reactions involving the cathode and electrolyte during the charge-discharge processes are included.We also provide stability perspectives on protecting the Li metal anodes and propose design principles for realizing high-performance LABs.

Designing a photo-assisted Co-C_(3)N_(4) cathode for high performance Li-O_(2) batteries

Li-O_(2) batteries with extremely high specific energy density have been regarded as a kind of promising successor to current Li-ion batteries.However,the high charge overpotential for the decomposition of Li_(2)O_(2) discharge product reduces the energy efficiency and triggers a series of side reactions that cause the Li-O_(2) batteries to have a limited lifetime.Herein,Co-doped C_(3)N_(4)(Co-C_(3)N_(4))photocatalysts were designed by an in situ thermal evaporation method to take advantage of the photo-assisted charging technology to conquer the shortcomings of Li-O_(2) batteries encountered in the charge process.Different from the commonly used photocatalysts,the Co-C_(3)N_(4) photocatalysts perform well no matter with and without illumination,owing to the Co doping induced conductivity and electrocatalytic ability enhancement.This makes the Co-C_(3)N_(4) reduce the charge and discharge overpotentials and improve the cycling performance of Li-O_(2) batteries(from 20 to 106 cycles)without illumination.While introducing illumination,the performance can be further improved:Charge voltage reduces to 3.3 V,and the energy efficiency increases to 84.84%,indicating that the Co-C_(3)N_(4) could behave as a suitable photocathode for Li-O_(2) batteries.Besides,the low charge voltage and the continuous illumination together weaken the corrosion of the Li anode,making the long-term high-efficiency operation of Li-O_(2) batteries no longer just extravagant hope.

Gel electrolyte via in situ polymerization to promote durable lithium-air batteries

Aprotic lithium-air batteries(LABs)have been known as the holy grail of energy storage systems due to their extremely high energy density.However,their real-world application is still hindered by the great challenges from the Li anode side,like dendrite growth and corrosion reactions,thus a pure oxygen atmosphere is usually adopted to prolong the lifetime of LABs,which is a major obstacle to fully liberate the energy density advantages of LABs.Here,a gel polymer electrolyte has been designed through in-situ polymerization of 1,3-dioxolane(DOL)by utilizing the unique semi-open nature of LABs to protect the Li anode to conquer its shortcomings,enabling the high-performance running of LABs in the ambient air.Unlike common liquid electrolytes,the in-situ formed gel polymer electrolyte could facilitate constructing a gradient SEl film with the gradual decrease of organic components from top to bottom,preventing the Li anode from dendrite growth and air-induced corrosion reactions and thus realizing durable Li repeated plating/stripping(2000h).Benefiting from the anode protection effects of the gradient SEI film,the LABs display a long lifetime of 17o cycles,paving an avenue for practical,long-term,and high-efficiency operation of LABs.

Effect of Nitrogen and Sulfur Co‑Doped Graphene on the Electrochemical Hydrogen Storage Performance of Co_(0.9)Cu_(0.1)Si Alloy

Co_(0.9)Cu_(0.1)Si alloy was prepared by mechanical alloying method.Nitrogen-doped graphene(NG)and nitrogen–sulfur codoped graphene(NSG)were prepared by hydrothermal method.5 wt%graphene oxide,NG and NSG were doped into Co_(0.9)Cu_(0.1)Si alloy,respectively,by ball milling to improve the electrochemical hydrogen storage performance of the composite material.X-ray diffraction and scanning electron microscopy were used to characterize the structure and morphology of the composite material,and the LAND battery test system and three-electrode battery system were used to test the electrochemical performance of the composite material.The composite material showed better discharge capacity and better cycle stability than the pristine alloy.In addition,in order to study the optimal ratio of NSG,3%,5%,7%and 10%of NSG were doped into Co_(0.9)Cu_(0.1)Si alloy,respectively.Co_(0.9)Cu_(0.1)Si alloy doped with 5%NSG had the best performance among all the samples.The best discharge capacity was 580.1 mAh/g,and its highest capacity retention rate was 64.1%.The improvement in electrochemical hydrogen storage performance can be attributed to two aspects.On the one hand,the electrocatalytic performance of graphene is improved by co-doping nitrogen and sulfur,on the other hand,graphene has excellent electrical conductivity.

Hierarchical Co3O4 porous nanowires as an efficient bifunctional cathode catalyst for long life Li-O2 batteries

层次公司 < 潜水艇 class= “ a-plus-plus ” > 3 O < 潜水艇 class= “ a-plus-plus ” > 4 多孔的 nanowires (NW ) 用锻烧跟随的一个热水的方法被综合了。当在非水的Li氧电池作为阴极催化剂采用了时，公司<潜水艇class=“ a-plus-plus ”> 3 O <潜水艇class=“ a-plus-plus ”> 4 NW 有效地两个都改进双程的效率和骑车的稳定性，它能被归因于公司的高催化的活动<潜水艇class=“ a-plus-plus ”> 3 O <潜水艇class=“ a-plus-plus ”>为氧减小反应和氧进化反应的 4 NW 分别地在分泌物和费用期间处理。

Stabilizing effects of atomic Ti doping on high-voltage high-nickel layered oxide cathode for lithium-ion rechargeable batteries

High-voltage high-nickel lithium layered oxide cathodes show great application prospects to meet the ever-increasing demand for further improvement of the energy density of rechargeable lithium-ion batteries(LIBs)mainly due to their high output capacity.However,severe bulk structural degradation and undesired electrode-electrolyte interface reactions seriously endanger the cycle life and safety of the battery.Here,2 mol%Ti atom is used as modified material doping into LiNi_(0.8)Co_(0.2)Mn_(0.2O2)(NCM)to reform LiNi_(0.6)Co_(0.2)Mn_(0.18)Ti_(0.02)O_(2)(NCM-Ti)and address the long-standing inherent problem.At a high cut-off voltage of 4.5 V,NCM-Ti delivers a higher capacity retention ratio(91.8%vs.82.9%)after 150 cycles and a superior rate capacity(118 vs.105 mAh·g^(-1))at the high current density of 10 C than the pristine NCM.The designed high-voltage full battery with graphite as anode and NCM-Ti as cathode also exhibits high energy density(240 Wh·kg^(-1))and excellent electrochemical performance.The superior electrochemical behavior can be attributed to the improved stability of the bulk structure and the electrode-electrolyte interface owing to the strong Ti-O bond and no unpaired electrons.The in-situ X-ray diffraction analysis demonstrates that Ti-doping inhibits the undesired H2-H3 phase transition,minimizing the mechanical degradation.The ex-situ TEM and X-ray photoelectron spectroscopy reveal that Ti-doping suppresses the release of interfacial oxygen,reducing undesired interfacial reactions.This work provides a valuable strategic guideline for the application of high-voltage high-nickel cathodes in LIBs.

Improved electrochemical hydrogen storage capacity of Ti45Zr38Ni17 quasicrystal by addition of ZrH2

Ti_(45)Zr_(38)Ni_(17)+ x ZrH_2(x = 5, 10, 15 and 20 wt%) composite materials are produced by ball milling for 20 min.The results of XRD measurement show that the composite materials contain icosahedral quasicrystal phase(I-phase), FCC phase with a Ti_2Ni type crystal and C14 Laves phase. After adding ZrH_2, the composite materials include not only the individual phases mentioned above, but also the Zr H phase. These composite materials are used as the negative electrode material of the nickel-metal hydride batteries.The electrochemical hydrogen storage characteristics of the material after adding Zr H is investigated. The Ti_(45)Zr_(38)Ni_(17)+ x ZrH_2(x = 5, 10, 15 and 20 wt%) composite material has reached the maximum discharge capacity(83.2 m A h/g) when x equals 10. This maximum discharge capacity is much higher than that of Ti_(45)Zr_(38)Ni_(17) alloy without Zr H. After adding ZrH_2,the high-rate discharge ability and the cycling stability are enhanced simultaneously. The improvement of the electrochemical properties can be attributed to the synergistic effects of ZrH_2, and the synergistic effects in the composite electrodes are probably attributed to the entry of most of hydrogen atoms from weakly bond strength of the Zr-H to the I-phase structure in electrochemical reaction.

Establishment of a new molecular model for mercury determination verified by single crystal X-ray diffraction,spectroscopic analysis and biological potentials

A wide variety of molecular probes have been developed for real-time analysis,but most of organic fluorophores possess small Stokes shifts and self-absorption or inner filter effect that could not be avoided.In this study,a new dicyanoisophorone-based derivative(E)-0-(4-(2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)phenyl)diphenylphosphinothioate(λ_(ex)=405 nm,X_(em)=551 nm,denoted as ICM-S) with strong push-pull electron effect has been afforded and it exhibits red shift for absorption from 407 nm to 426 nm with distinct color change from pale yellow to deep yellow upon exposure to Hg~(2+).Moreover,an easily distinguishable fluorescence color change follows the route from green,yellow to red in the presence of Hg~(2+) over the range of 0-90 μmol/L(detection limit=137 nmol/L)can be observed by the naked eye under a UV lamp irradiation.Chlorodiphenylphosphine and sublimedsulfur are incorpo rated as re s ponsive sites and P-O bond has been cleaved upon the addition of mercu ry ions.During the recognition process,such dicyanoisophorone dye(ICM-S) has been evolved to 2-(3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene) malononitrile(ICM-OH).Clear evidences in the chemical processes can be identified via single crystal X-ray diffraction,spectroscopic analysis,photophysical studies and titration experiments.With the aim of exploring its potential in biological systems,its in vitro responses to Hg~(2+) have been evaluated in 293 T cells and the effectiveness in zebrafish model has also been verified.

Multidimensional regulation of Ti-Zr-Cr-Mn hydrogen storage alloys via Y partial substitution

High density and safe storage of hydrogen are the preconditions for the large-scale application of hydrogen energy.Herein,the hydrogen storage properties of Ti_(0.6)Zr_(0.4)Cr_(0.6)Mn_(1.4) alloys are systematically studied by introducing Y element instead of Ti element through vacuum arc melting.After the partial substitution of Y,a second phase of rare earth oxide is added in addition to the main suction hydrogen phase,C14 Laves phase.Thanks to the unique properties of rare earth elements,the partial substitution of Y can not only improve the activation properties and plateau pressure of the alloys,but also increase the effective hydrogen storage capacity of the alloys.The comprehensive properties of hydrogen storage alloys are improved by multidimensional regulation of rare earth elements.Among them,Ti_(0.552)Y_(0.048)Zr_(0.4)Cr_(0.6)Mn_(1.4) has the best comprehensive performance.The alloy can absorb hydrogen without activation at room temperature and 5 MPa,with a maximum hydrogen storage capacity of 1.98 wt.%.At the same time,it reduces the stability of the hydride and the enthalpy change value,making it easier to release hydrogen.Through theoretical analysis and first-principle simulation,the results show that the substitution of Y element reduces the migration energy barrier of hydrogen and the structural stability of the system,which is conducive to hydrogen evolution.The alloy has superior durability compared to the original alloy,and the capacity retention rate was 96.79%after 100 hydrogen absorption/desorption cycles.