Energy storage is an ever-growing global concern due to increased energy needs and resource exhaustion.Sodium-ion batteries(SIBs)have called increasing attention and achieved substantial progress in recent years owing...Energy storage is an ever-growing global concern due to increased energy needs and resource exhaustion.Sodium-ion batteries(SIBs)have called increasing attention and achieved substantial progress in recent years owing to the abundance and even distribution of Na resources in the crust,and the predicted low cost of the technique.Nevertheless,SIBs still face challenges like lower energy density and inferior cycling stability compared to mature lithium-ion batteries(LIBs).Enhancing the electrochemical performance of SIBs requires an in-deep and comprehensive understanding of the improvement strategies and the underlying reaction mechanism elucidated by in situ techniques.In this review,commonly applied in situ techniques,for instance,transmission electron microscopy(TEM),Raman spectroscopy,X-ray diffraction(XRD),and X-ray absorption near-edge structure(XANES),and their applications on the representative cathode and anode materials with selected samples are summarized.We discuss the merits and demerits of each type of material,strategies to enhance their electrochemical performance,and the applications of in situ characterizations of them during the de/sodiation process to reveal the underlying reaction mechanism for performance improvement.We aim to elucidate the composition/structure-per formance relationship to provide guidelines for rational design and preparation of electrode materials toward high electrochemical performance.展开更多
Organic compounds represent an appealing group of electrode materials for rechargeable batteries due to their merits of biomass,sustainability,environmental friendliness,and processability.Disodium terephthalate(Na_(2...Organic compounds represent an appealing group of electrode materials for rechargeable batteries due to their merits of biomass,sustainability,environmental friendliness,and processability.Disodium terephthalate(Na_(2)C_(8)H_(4)O_(4),Na_(2)TP),an organic salt with a theoretical capacity of 255 mAh·g^(-1),is electroactive towards both lithium and sodium.However,its electrochemical energy storage(EES)process has not been directly observed via in situ characterization techniques and the underlying mechanisms are still under debate.Herein,in situ Raman spectroscopy was employed to track the de/lithiation and de/sodiation processes of Na2TP.The appearance and then disappearance of the–COOLi Raman band at 1625 cm^(-1) during the de/lithiation,and the increase and then decrease of the–COONa Raman band at 1615 cm^(-1) during the de/sodiation processes of Na2TP elucidate the one-step with the 2Li+or 2Na+transfer mechanism.We also found that the inferior cycling stability of Na2TP as an anode for sodium-ion batteries(SIBs)than lithium-ion batteries(LIBs)could be due to the larger ion radium of Na+than Li+,which results in larger steric resistance and polarization during EES.The Na2TP,therefore,shows greater changes in spectra during de/sodiation than de/lithiation.We expect that our findings could provide a reference for the rational design of organic compounds for EES.展开更多
As state-of-the-art electrochemical energy conversion and storage(EECS)techniques,fuel cells and rechargeable batteries have achieved great success in the past decades.However,modern societies’ever-growing demand in ...As state-of-the-art electrochemical energy conversion and storage(EECS)techniques,fuel cells and rechargeable batteries have achieved great success in the past decades.However,modern societies’ever-growing demand in energy calls for EECS devices with high efficiency and enhanced performance,which mainly rely on the rational design of catalysts,electrode materials,and electrode/electrolyte interfaces in EESC,based on in-deep and comprehensive mechanistic understanding of the relevant electrochemical redox reactions.Such an understanding can be realized by monitoring the dynamic redox reaction processes under realistic operation conditions using in situ techniques,such as in situ Raman,Fourier transform infrared(FTIR),and X-ray diffraction(XRD)spectroscopy.These techniques can provide characteristic spectroscopic information of molecules and/or crystals,which are sensitive to structure/phase changes resulted from different electrochemical working conditions,hence allowing for intermediates identification and mechanisms understanding.This review described and summarized recent progress in the in situ studies of fuel cells and rechargeable batteries via Raman,FTIR,and XRD spectroscopy.The applications of these in situ techniques on typical electrocatalytic electrooxidation reaction and oxygen reduction reaction(ORR)in fuel cells,on representative high capacity and/or resource abundance cathodes and anodes,and on the solid electrolyte interface(SEI)in rechargeable batteries are discussed.We discuss how these techniques promote the development of novel EECS systems and highlight their critical importance in future EECS research.展开更多
Surface-enhanced Raman spectroscopy(SERS)has advanced significantly since its inception.Numerous experimental and theoretical efforts have been made to understand the SERS effect and demonstrate its potential.Due to i...Surface-enhanced Raman spectroscopy(SERS)has advanced significantly since its inception.Numerous experimental and theoretical efforts have been made to understand the SERS effect and demonstrate its potential.Due to its extremely high sensitivity and selectivity and ability to provide molecular fingerprint information,SERS has a wide range of applications in surface and interfacial chemistry,energy,materials,biomedicine,environmental analysis,etc.This review aims to provide readers with an understanding of the principles,methodologies,and applications of SERS.We briefly introduce the fundamental theory of the SERS enhancement mechanism and summarize the details of the preparation of SERS-active substrates.Recent applications of SERS in energy systems are then highlighted,including probing surface reactions and interfacial charge transfer of batteries and electrocatalysts.Finally,the challenges and prospects of SERS research are discussed.展开更多
Electrochemical conversion of CO_(2)into liquid fuels provides an efficient way to store the renewable energy in the production of fuels and chemicals.However,effectively converting CO_(2)to ethanol remains extremely ...Electrochemical conversion of CO_(2)into liquid fuels provides an efficient way to store the renewable energy in the production of fuels and chemicals.However,effectively converting CO_(2)to ethanol remains extremely challenging due to the low activity and selectivity.Herein,we achieve a high ethanol Faradaic efficiency(FE)as high as 85%on Ag nanowires(NWs)for CO_(2)electroreduction at-0.95 V.X-ray photoelectron spectroscopy and electrochemical experiments prove that such Ag NWs are partially oxidized.Operando Raman spectroscopy finds the important CO intermediate adsorbed on partially oxidized Ag NWs,facilitating the ethanol formation.Density functional theory calculations prove that the reaction energy of CO coupling with the*CHO to*COCHO intermediate on the partially oxidized Ag NWs is smaller than that on the surface of Cu,which explains why the ethanol FE of such partially oxidized Ag NWs can exceed that of Cu,and therefore is the most favorable pathway for the formation of C_(2)products on partially oxidized Ag NWs.This study provides a new insight to design efficient catalysts and investigate the mechanisms to improve the selectivity.展开更多
Benefiting from a principally contaminant-free and well-defined surface,single-crystal electrodes offer new insights into interfacial processes and are important in electrochemistry.The early impetus for using single-...Benefiting from a principally contaminant-free and well-defined surface,single-crystal electrodes offer new insights into interfacial processes and are important in electrochemistry.The early impetus for using single-crystal electrodes in electrocatalysis was to investigate the surface structure at the atomic level for the reactions that are sensitive to the surface.These studies were usually performed in an ultra-high vacuum with atomic force microscopy(AFM),scanning tunneling microscope(STM),and X-ray methods to avoid the contamination.However,such characterizations are limited in their ability to identify chemical species definitively,a limitation that has similarly plagued the study of single-crystals.Recent advances in shellisolated nanoparticle-enhanced Raman spectroscopy(SHINERS)have enabled the detection of reaction intermediates on singlecrystal electrodes,in which shell-isolated nanoparticles on the single-crystal electrode can enhance the Raman signal from the surface,without changing the surface structure and electrochemical response.Thus,this work aims to review recent advances in Raman spectroelectrochemical studies on single-crystal electrode surfaces.The discussion focuses on how SHINERS technology has enabled the effective detection of intermediate species and,when combined with the electrochemical method,has yielded novel insights into the dynamic evolution of surface structure and electrocatalytic reaction mechanisms.Finally,the challenges and future of single-crystal electrodes are introduced.展开更多
基金supported by the National Natural Science Foundation of China(22005130,21925404,21902137,21991151,and 22021001)the National Key Research and Development Program of China(2019YFA0705400 and 2020YFB1505800)the Natural Science Foundation of Fujian Province of China(2021J01988)。
文摘Energy storage is an ever-growing global concern due to increased energy needs and resource exhaustion.Sodium-ion batteries(SIBs)have called increasing attention and achieved substantial progress in recent years owing to the abundance and even distribution of Na resources in the crust,and the predicted low cost of the technique.Nevertheless,SIBs still face challenges like lower energy density and inferior cycling stability compared to mature lithium-ion batteries(LIBs).Enhancing the electrochemical performance of SIBs requires an in-deep and comprehensive understanding of the improvement strategies and the underlying reaction mechanism elucidated by in situ techniques.In this review,commonly applied in situ techniques,for instance,transmission electron microscopy(TEM),Raman spectroscopy,X-ray diffraction(XRD),and X-ray absorption near-edge structure(XANES),and their applications on the representative cathode and anode materials with selected samples are summarized.We discuss the merits and demerits of each type of material,strategies to enhance their electrochemical performance,and the applications of in situ characterizations of them during the de/sodiation process to reveal the underlying reaction mechanism for performance improvement.We aim to elucidate the composition/structure-per formance relationship to provide guidelines for rational design and preparation of electrode materials toward high electrochemical performance.
基金supported by the National Natural Science Foundation of China(Nos.22005130,22272069,22004054,and 21925404)the Natural Science Foundation of Fujian Province of China(Nos.2021J01988 and 2020J05163).
文摘Organic compounds represent an appealing group of electrode materials for rechargeable batteries due to their merits of biomass,sustainability,environmental friendliness,and processability.Disodium terephthalate(Na_(2)C_(8)H_(4)O_(4),Na_(2)TP),an organic salt with a theoretical capacity of 255 mAh·g^(-1),is electroactive towards both lithium and sodium.However,its electrochemical energy storage(EES)process has not been directly observed via in situ characterization techniques and the underlying mechanisms are still under debate.Herein,in situ Raman spectroscopy was employed to track the de/lithiation and de/sodiation processes of Na2TP.The appearance and then disappearance of the–COOLi Raman band at 1625 cm^(-1) during the de/lithiation,and the increase and then decrease of the–COONa Raman band at 1615 cm^(-1) during the de/sodiation processes of Na2TP elucidate the one-step with the 2Li+or 2Na+transfer mechanism.We also found that the inferior cycling stability of Na2TP as an anode for sodium-ion batteries(SIBs)than lithium-ion batteries(LIBs)could be due to the larger ion radium of Na+than Li+,which results in larger steric resistance and polarization during EES.The Na2TP,therefore,shows greater changes in spectra during de/sodiation than de/lithiation.We expect that our findings could provide a reference for the rational design of organic compounds for EES.
基金supported by the National Key Research and Development Program of China(Nos.2020YFB1505800 and 2019YFA0705400)the National Natural Science Foundation of China(NSFC)(Nos.201925404,21902137,22005130,and 22021001)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.20720210069 and 20720210043)the Science and Technology Planning Project of Fujian Province(No.2019Y4001).
文摘As state-of-the-art electrochemical energy conversion and storage(EECS)techniques,fuel cells and rechargeable batteries have achieved great success in the past decades.However,modern societies’ever-growing demand in energy calls for EECS devices with high efficiency and enhanced performance,which mainly rely on the rational design of catalysts,electrode materials,and electrode/electrolyte interfaces in EESC,based on in-deep and comprehensive mechanistic understanding of the relevant electrochemical redox reactions.Such an understanding can be realized by monitoring the dynamic redox reaction processes under realistic operation conditions using in situ techniques,such as in situ Raman,Fourier transform infrared(FTIR),and X-ray diffraction(XRD)spectroscopy.These techniques can provide characteristic spectroscopic information of molecules and/or crystals,which are sensitive to structure/phase changes resulted from different electrochemical working conditions,hence allowing for intermediates identification and mechanisms understanding.This review described and summarized recent progress in the in situ studies of fuel cells and rechargeable batteries via Raman,FTIR,and XRD spectroscopy.The applications of these in situ techniques on typical electrocatalytic electrooxidation reaction and oxygen reduction reaction(ORR)in fuel cells,on representative high capacity and/or resource abundance cathodes and anodes,and on the solid electrolyte interface(SEI)in rechargeable batteries are discussed.We discuss how these techniques promote the development of novel EECS systems and highlight their critical importance in future EECS research.
基金supported by the National Key Research and Development Program of China (2020YFB1505800)the National Natural Science Foundation of China (22005130,21925404,22174165,21902137,and 21991151)+1 种基金the China Postdoctoral Science Foundation (Bx20220187)the Natural Science Foundation of Fujian Province of China (2021J01988).
文摘Surface-enhanced Raman spectroscopy(SERS)has advanced significantly since its inception.Numerous experimental and theoretical efforts have been made to understand the SERS effect and demonstrate its potential.Due to its extremely high sensitivity and selectivity and ability to provide molecular fingerprint information,SERS has a wide range of applications in surface and interfacial chemistry,energy,materials,biomedicine,environmental analysis,etc.This review aims to provide readers with an understanding of the principles,methodologies,and applications of SERS.We briefly introduce the fundamental theory of the SERS enhancement mechanism and summarize the details of the preparation of SERS-active substrates.Recent applications of SERS in energy systems are then highlighted,including probing surface reactions and interfacial charge transfer of batteries and electrocatalysts.Finally,the challenges and prospects of SERS research are discussed.
基金supported by grants from the National Natural Science Foundation of China(22174165,21925404,22002036,and21908253)the Natural Science Foundation of Guangdong Province(2019A1515011117)+1 种基金Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)the Natural Science Foundation of Henan Province(202300410234)。
文摘Electrochemical conversion of CO_(2)into liquid fuels provides an efficient way to store the renewable energy in the production of fuels and chemicals.However,effectively converting CO_(2)to ethanol remains extremely challenging due to the low activity and selectivity.Herein,we achieve a high ethanol Faradaic efficiency(FE)as high as 85%on Ag nanowires(NWs)for CO_(2)electroreduction at-0.95 V.X-ray photoelectron spectroscopy and electrochemical experiments prove that such Ag NWs are partially oxidized.Operando Raman spectroscopy finds the important CO intermediate adsorbed on partially oxidized Ag NWs,facilitating the ethanol formation.Density functional theory calculations prove that the reaction energy of CO coupling with the*CHO to*COCHO intermediate on the partially oxidized Ag NWs is smaller than that on the surface of Cu,which explains why the ethanol FE of such partially oxidized Ag NWs can exceed that of Cu,and therefore is the most favorable pathway for the formation of C_(2)products on partially oxidized Ag NWs.This study provides a new insight to design efficient catalysts and investigate the mechanisms to improve the selectivity.
基金supported by the National Key Research and Development Program of China (2020YFB1505800)the National Natural Science Foundation of China (21925404,22005130,and 21991151)the China Postdoctoral Science Foundation (BX20220187)。
文摘Benefiting from a principally contaminant-free and well-defined surface,single-crystal electrodes offer new insights into interfacial processes and are important in electrochemistry.The early impetus for using single-crystal electrodes in electrocatalysis was to investigate the surface structure at the atomic level for the reactions that are sensitive to the surface.These studies were usually performed in an ultra-high vacuum with atomic force microscopy(AFM),scanning tunneling microscope(STM),and X-ray methods to avoid the contamination.However,such characterizations are limited in their ability to identify chemical species definitively,a limitation that has similarly plagued the study of single-crystals.Recent advances in shellisolated nanoparticle-enhanced Raman spectroscopy(SHINERS)have enabled the detection of reaction intermediates on singlecrystal electrodes,in which shell-isolated nanoparticles on the single-crystal electrode can enhance the Raman signal from the surface,without changing the surface structure and electrochemical response.Thus,this work aims to review recent advances in Raman spectroelectrochemical studies on single-crystal electrode surfaces.The discussion focuses on how SHINERS technology has enabled the effective detection of intermediate species and,when combined with the electrochemical method,has yielded novel insights into the dynamic evolution of surface structure and electrocatalytic reaction mechanisms.Finally,the challenges and future of single-crystal electrodes are introduced.
