股权众筹企业后续融资绩效的影响因素研究

股权众筹是一种新型的融资模式,具有门槛低、效率高、成本低等优势,为中小企业拓展了融资渠道,吸收了大众闲散资金。但这种新兴的融资模式也存在诸多问题,如法律环境、信用体系、知识产权保护和社会认知等,可能影响企业高质量发展,让投资者的决策面临风险。本文基于信号理论,利用股权众筹平台Seedrs和Crunchbase的相关数据,从项目特征、众筹绩效、获得的广告效应三个方面,对完成股权众筹的初创企业的后续融资绩效影响因素进行了研究。研究发现,项目特征中的项目估值、目标金额、出让股权份额、政策优惠程度,以及众筹绩效中的先前的融资经历、获得的广告效应中的投资者数量,均会显著正向影响后续融资绩效(是否获得后续融资、后续融资所需时间或后续融资金额)。除此之外,项目视频介绍长度、所在城市等级、公司经营对象、数字化程度、融资完成时间、公司年龄对于后续融资也有一定影响。本文研究结论可为投资者、创业者和平台提供有效的决策参考。

Grafting polymeric sulfur onto carbon nanotubes as highly-active cathode for lithium–sulfur batteries

Lithium–sulfur(Li–S)batteries are being explored as promising advanced energy storage systems due to their ultra-high energy density.However,fast capacity fading and low coulombic efficiency,resulting from the dissolution of polysulfides,remain a serious challenge.Compared to weak physical adsorptions or barriers,chemical confinement based on strong chemical interaction is a more effective approach to address the shuttle issue.Herein,we devise a novel polymeric sulfur/carbon nanotube composite for Li–S battery,for which 2,5-dithiobiurea is chosen as the stabilizer of long-chain sulfur.This offers chemical bonds which bridge the polymeric sulfur and carbon nanotubes.The obtained composite can deliver an ultra-high reversible capacity of 1076.2 m Ahg^-1(based on the entire composite)at the rate of 0.1 C with an exceptional initial Coulombic efficiency of 96.2%,as well as remarkable cycle performance.This performance is mainly attributed to the reaction reversibility of the obtained polymeric sulfur-based composite during the discharge/charge process.This was confirmed by density functional theory calculations for the first time.

纳米银、金溶胶的电化学合成及其基本胶体性质——物理化学综合实验设计

电化学和胶体体系基础理论是大学本科物理化学学习的重要内容。通过综合化学实验设计,以直接电化学还原方法制备纳米银、金溶胶,利用紫外-可见光谱分析溶胶粒子的特征吸收光谱,并运用循环伏安法探讨表面活性剂的稳定作用和纳米金属溶胶的形成机理,从而提高学生的基础知识综合运用能力与综合实验技能,适合在大学化学及其相关专业的综合化学实验中推广。

The dispersion of iron nitride among porous carbon fibers to enhance redox conversion for high-performance zinc-iodine batteries

To address the insulating nature and the shuttle effect of iodide species that would deteriorate the battery performance,herein iron nitride is well-dispersed into porous carbon fibers with good flexibility via the facile electrospinning method and subsequent pyrolysis.The polyacrylonitrile precursor introduces the nitrogen doping under thermal treatment while the addition of iron acetylacetonate leads to the insitu formation of iron nitride among the carbon matrix.The crucial pyrolysis procedure is adjustable to determine the hierarchical porous structure and final composition of the novel carbon fiber composites.As the self-supporting electrode for loading iodine,the zinc-iodine battery exhibits a large specific capacity of 214 mAh/g and good cycling stability over 1600 h.In the combination of in-situ/ex-situ experimental measurements with the theoretical analysis,the in-depth understanding of intrinsic interaction between composited support and iodine species elucidates the essential mechanism to promote the redox kinetics of iodine via the anchoring effect and electrocatalytic conversion,thus improving cycling life and rate performance.Such fundamental principles on the basic redox conversion of iodine species would evoke the rational design of advanced iodine-based electrodes for improving battery performance.

Rational design of carbon-based electrocatalysts for enhancing redox reactions in rechargeable metal batteries

Exploitation of the efficient and cost-effective electrode materials is urgently desirable for the development of advanced energy devices.With the unique features of good electronic conductivity,structure flexibility,and desirable physicochemical property,carbon-based nanomaterials have attracted enormous research attention as efficient electrode materials.Electronic and microstructure engineering of carbon-based nanomaterials are the keys to regulate the electrocatalytic properties for the specific redox reactions of advanced metal-based batteries.However,the critical roles of carbon-based electrocatalysts for rechargeable metal batteries have not been comprehensively discussed.With the basic introduction on the electronic and microstructure engineering strategies,we summarize the recent advances on the rational design of carbon-based electrocatalysts for the important redox reactions in various metal-air batteries and metal-halogen batteries.The relationships between the composition,structure,and the electrocatalytic properties of carbon-based materials were well-addressed to enhance the battery performance.The overview of present challenges and opportunities of the carbon-based active materials for future energy-related applications was also discussed.