研究生英文文献汇报化学化工.pptx

《研究生英文文献汇报化学化工.pptx》由会员分享，可在线阅读，更多相关《研究生英文文献汇报化学化工.pptx（21页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、1Literatures Source第1页/共21页Article structure1、Title and author2、AbstractPhase 4Phase 3Phase 2Phase 1Introduction 1、synthesis and characterization 2、LIB assembly 1、Results and Discussion 2、Conclusions 3、references第2页/共21页123 34 43 5AbstractContents IntroductionExperimental sectionResults and Discussi

2、on Conclusions第3页/共21页A promising strategy for large-scale fabrication of silicon(Si)nanotubesThe process began with preparation of silica nanotubes using rod-like NiN2H4 as a template and the resulting silica nanotubes were then converted to Si nanotubes by a thermal reduction process assisted with

3、 magnesium powder.The electrochemical properties of Si nanotubes were investigated as anode of lithium-ion batteries.It was demonstrated that the as-developed Si nanotubes showed significantly improved rate capability and long-term cycling performance compared with commercial silicon meshes.4Abstrac

4、t.第4页/共21页52、Introduction and Background Merits and applications of LIBsDrawbacks about anode materialsSilicon as a CandidatePreparation of Si nanotubes Introduction Introduction and and BackgroundBackground第5页/共21页61.1 Merits and applications of LIBsRechargeable lithium-ion batteries(LIBs)are consi

5、dered to be the most promising energy storage technology for next-generation portable electronic devices(e.g.,laptops,cell phones,cameras)and for powering electric vehicles(EVs)or hybrid electric vehicles(HEVs)due to their long cycle life and high specific capacity.Introduction第6页/共21页71.2 Drawbacks

6、 about anode materialsCurrent LIBs predominantly use graphite as anode material,which only has a theoretical capacity of around 372 mAh g1.Such a limited capacity significantly lags behind the rapidly growing energy demand for various electronic products.（补充：过剩容量、单位体积容量）Introduction第7页/共21页Introduct

7、ion1.3 Silicon as a CandidateSilicon(Si)has been regarded as the most promising and competitive candidate to replace graphite anode material,because it can be alloyed/de-alloyed with lithium and offers a theoretical capacity as high as 4200 mAh g1 with a low working potential.(0.4V Vs Li+/Li)（merits

8、）The volume change in the course of the battery operation would cause severe mechanical damage of Si electrodes and leads to rapid capacity fading during cycling.(drawbacks)8第8页/共21页9Introduction1.3 Silicon as a CandidateMany reports aiming to the volume changeNanostructured Si materials,such as nan

9、owires,nanofilms,nanotubes,have been widely reported to alleviate the pulverization problem because absolute local volume change is expected to be minimized in nanostructures.Another option is to blend Si-based materials with a buffering matrix to dissipate local mechanical stress and the large volu

10、metric change of Si anode during the cycling process.第9页/共21页Introduction1.4 Preparation of Si nanotubes Si nanotubes can be prepared by using anodic aluminum oxide(AAO)or ZnO rod as a template,but it is still a great challenge to achieve large-scale production using these methods.The Sandhage group

11、 reported an effective method to synthesize silicon from reducing silica via magnesiothermic reduction，which has been successfully used for fabricating various porous silicon nanostructures.10第10页/共21页Experimental section112.1 Synthesis of Si nanotubes Fig.1.(a)Schematic illustration for the synthes

12、is of Si nanotubes反相胶团软模板法反相胶团软模板法联氨合镍为模板联氨合镍为模板可逆可逆第11页/共21页Experimental sectionBrig 58Cyclohexane 50 Si nanotube Mg+Argon660，3hStirring15 min+NiCl2+Hydrazine hydrateStirring15 min DEA、TEOSStirring15 mincentrifuIPA、H2OwashingSilica nanotubeSilica nanotubeHCletchingH2Owashing2.1 Synthesis of Si nano

13、tubes 第12页/共21页Experimental section2.2 LIBs assembly and characterization 13Working electrode active materials，60%acetylene black，30%binder(PVDF，10%）electrolyte1M LiPF6 dissolved in EC:DMC=4:6the counter and reference eletrodeA lithium pellet第13页/共21页2.2 LIBs assembly and characterization14Experimen

14、tal sectionThe morphology and crystallographic structureThe pore size and a BET surface areaElectrochemical performance SEM、TEM、SAED、XRDN2 adsorption and desorption measurements Land battery tester system第14页/共21页Results and Discussion15Fig.1.(b)SEM image and TEM image(inset)of silica nanotubes;(c)S

15、EM image,(d)TEM image,and(e)SAED patterns of Si nanotubes.SiO2 纳米管：直径约15nm,长度约为50-200nm;Si 纳米管形貌类似金刚石结构，结晶良好。第15页/共21页16Results and DiscussionFig.2.(a)XRD patterns and(b)nitrogen adsorption/desorption isotherm curves at 77 K and pore size distribution of the Si nanotubes(inset)SiO2：无定形结构：无定形结构Si：晶型：

16、晶型氮吸附：中大孔径，氮吸附：中大孔径，单位质量体积单位质量体积BET面积面积第16页/共21页Results and Discussion17Fig.2.the first and second charge/discharge profiles for(c)silicon meshes 325,(d)Si nanotubes LIB anode at 0.5 C;平台平台起始容量比较起始容量比较库伦效率比较库伦效率比较第17页/共21页18Results and DiscussionFig.2cyclic performance and rate capability of(e)silic

17、on meshes 325 and(f)Si nanotubes LIB anode at different rates.10周容量损失周容量损失90周后比容量周后比容量与文献与文献5纳米硅纳米硅阵列，文献阵列，文献63D多孔硅颗粒比较多孔硅颗粒比较比容量低的原因：比容量低的原因：硅的不完全还原硅的不完全还原第18页/共21页The electrochemical performance of these Si nanotubes,offering a capacity of around 1000 mAh g1 with good rate capability and cycle sta

18、bility,is very attractive for commercial applications compared with commercial silicon meshes and graphite electrodes.The nanotube structure in Si nanotubes could be the key factor for the decent performance because(1)to provide enough space for alleviating the effect of volume change,and(2)favorabl

19、e properties,such as the increased surface area accessible to the electrolyte,allow Li+to intercalate at interior and exterior surfaces of the nanotubes and reasonably improve the rate capability.(3)Si nanotubes have an amorphous SiOx matrix,which could be beneficial to stabilize the Sielectrolyte interface and facilitate the formation of a stable SEI,thereby contributing to the enhanced long-cycle performance.19 Conclusions 第19页/共21页第20页/共21页21感谢您的观看！第21页/共21页