In-Situ Electrochemical Reflective IR Spectroscopy Based On Tunable IR-FEL And OEMS Study In Fuel Cell And Lithium Ion Batteries

The development of scientific instruments and instrumental methods have played a critical role in modern science.A novel instrumental method could help researchers to discover new experimental phenomena and validate new theories,ultimately promote advances in science,technology,and industries.The development,utilization and environmental protection of energy have become one of the most concerned issues of multinational governments and corporate research institutions in recent years.with the international energy issucs have become increasingly prominent,government of most countries have given a high priority and increased input to new energy resourcerelated fields,like Fuel Cells,Lithium-ion battery,and Li-O2 battery.Herein,it's necessary to develop new spectroscopic instruments and related in-situ instrumental methods to solve the crucial problems of the energy-related field.This thesis relies on the National Key Scientific Instrument and Equipment Development Project named "Tunable Infrared Laser for Fundamentals of Energy Chemistry(FELiChEM)" to present the design of reflective infrared spectroscopy system of Photo-Detection research station.This thesis also presents the membranebased OEMS(Online Electrochemistry mass spectroscopy)and in-situ product detection system for Direct Alcohol Fuel Cell,H2/O2 PEMFC,Lithium-ion battery,and Li-O2 battery.The main content is as follows:1.Combine the heated-vacuum vaporizing adapter and capillaries to achieve the continuous operando product monitor of Direct Alcohol Fuel Cell,H2/O2 PEMFC from the catalyst layer and the flow channel.In OCP condition-0.1 M acetic acid was detected.This means O2 permeated from the Pt/C cathode to the PtRu/C anode through the Nafion membrane.Ethanol was oxidized into acetic acid through a chemical oxidation reaction(CH3CH2OH+O2? CH3COOH+H2O)catalyzed by PtRu without external circuit electron transfer.The O2 permeation not only wastes the ethanol but also reduces the cell voltage and toxic catalyst.The polarization curve shows in the catalyst layer the usage of ethanol was about 40%.No significant CO2 signal was detected,for C-C bond was difficult to break under PtRu/C catalyst condition.This method could also help to guide the design of the Fuel Cell component structure.In the outlet of the serpentine flow channel,the concentration of acetic acid was only 0.86 mM/L which means most ethanol was exhausted directly.2.We set up the in-situ gas-product detection method for LIB and Li-O2 battery.Relying on this method we investigate the effect of LAPF and NHP modification to Lirich manganese-based layered cathode materials.The results show the LAPF could block the surface of highcenergy cathode containing Ni4+ from electrolyte to reduce the electrolyte decomposition.NHP could activate the surface Li2MnO3 to obstruct the release of O2,Since NHP only activates the surface not the bulk phase Li2MnO3,the charging curve remained platform characteristics of the lithium-rich material,which also proves that the source of O2 in the lithium-rich manganese-based layered material is the surface rather than the bulk phase Li2MnO3.3.In the study of dual-ion battery,we used electrochemical mass spectrometry to study the effect of vinylene carbonate as an additive in the dual-ion battery.The electrochemical mass spectrometry method was used to compare the CO2,PF3,CH3CH2F and C2H4F2 in the charge and discharge of the battery with or without 3%VC.With the EIS and in-situ XRD characterization as secondary evidence,the existence of VC would inhibit the SEI film thickening phenomenon.4.In Li-O2 battery,the OEMS method could help us to calculate O2 and CO2 outgassing rates and evaluate O2 utilization.We investigate the effect of RuPC catalyst as additive in Li-O2 battery.The addition of RuPC helps to cut down the amount of CO2 released,reduce the polarization voltage and promote the utilization of O2.In DMSO electrolyte Li-O2 battery,the first time observed of the signal of dimethyl sulfide m/z=62 was as the direct proof of DMSO electro-decomposition.5.Rely on National Key Scientific Instrument and Equipment Development Project named "Tunable Infrared Laser for Fundamentals of Energy Chemistry(FELiChEM)"we design and build the reflective infrared spectroscopy system of Photo-Detection research station.At present,the light source project is still in progress,and the detection system is also in the construction stage.In this thesis,the optical path part,vacuum part,data acquisition part and electrochemical part of the detection system are introduced.After the completion of the whole project.This beam-line research station could use far-IR free-electron laser,mid-IR free-electron laser and normal FTIR as hte light source to support in-situ external/internal reflective electrochemical infrared spectroscopy and in-situ XPS research.This project would become the first open infrared free-electron laser user device in China.